Prevalence of sarcopenia in patients with surgical obstructive jaundice and its impact on clinical outcomes

Abstract

BACKGROUND

Sarcopenia is a clinical syndrome presented with progressive and generalized skeletal muscle loss and function dysfunction. Usually, it is considered an age-related process influenced by genetic, lifestyle factors, and diseases. Obstructive jaundice is one of the most common pathophysiological changes in patients needing hepatobiliary or pancreatic operations that can adversely affect the tissue and organ function throughout the human body. However, the effects of obstructive jaundice on the occurrence of sarcopenia remain unclear.

AIM

To investigate the incidence of sarcopenia in patients with surgical obstructive jaundice and the association of sarcopenia with postoperative outcome.

METHODS

This cross-sectional study was conducted from December 2019 to January 2024. Data retrieved included patient demographics, disease entities, sarcopenia-related parameters (including grip strength, 6-m walking time, and limb skeletal muscle mass index), postoperative complications, and length of hospital stay. Sarcopenia was confirmed using Asian Working Group standards. Logistic regression was used to analyze the relationship between total bilirubin level and sarcopenia. The factors influencing sarcopenia in patients with surgical obstructive jaundice and association of sarcopenia with postoperative complications were also investigated.

RESULTS

Overall, 1708 patients met the inclusion criteria, with a mean age of 60.09 ± 13.52 years (sex: 52.28% male). There were 383 patients (22.42%) with obstructive jaundice and 1325 (77.58%) without jaundice. Sarcopenia, low walking speed, low grip strength, and low limb skeletal muscle index were more prevalent in patients with obstructive jaundice than nonobstructive jaundice. The odds ratio (OR) for sarcopenia in patients with obstructive jaundice was 1.689 [95% confidence interval (CI): 1.295-2.203, P < 0.001], indicating that jaundice is a significant risk factor for sarcopenia. The occurrence of sarcopenia was higher in patients with severe obstructive jaundice than mild obstructive jaundice (39.3% vs 22.8%, P < 0.05). Obstructive jaundice was positively correlated with reduced walking speed (OR = 1.627, 95%CI: 1.185-2.234, P = 0.003) and decreased grip strength (OR = 1.669, 95%CI: 1.212-2.300, P = 0.002). Age (OR = 1.077, 95%CI: 1.040-1.114, P < 0.001) and body mass index (OR = 0.703, 95%CI: 0.630-0.784, P < 0.001) were independent risk factors of sarcopenia in patients with obstructive jaundice. Patients with obstructive jaundice and sarcopenia had a higher rate of postoperative complications (46.3% vs 33.1%, P = 0.032), longer postoperative hospital stays (11.33 ± 6.75 days vs 9.19 ± 7.32 days, P = 0.016), and longer total hospital stays (17.10 ± 7.69 days vs 15.98 ± 8.55 days, P = 0.032) than those without sarcopenia.

CONCLUSION

Sarcopenia is more prevalent in patients with obstructive jaundice and is positively correlated with the degree of jaundice. Sarcopenia prolongs hospital stays and is associate with postoperative complications.

Key Words: Obstructive jaundice; Sarcopenia; Bilirubin; Length of hospital stay; Postoperative complications

Core Tip: Atrophy of muscles adversely affects surgical treatment and prognosis for patients. As a result, sarcopenia has been receiving increasing attention. The occurrence of sarcopenia associated with hepatobiliary and pancreatic surgical diseases is influenced by various factors. Obstructive jaundice is a common symptom in patients with these diseases; however, few studies have investigated its effects on muscle function. Therefore, this study analyzed obstructive jaundice-related sarcopenia from different perspectives, aiming to provide theoretical support for understanding this condition.

INTRODUCTION

Sarcopenia is characterized by age-related muscular atrophy and decreased general functional status, which is associated with the increased possibility of adverse consequences, including falls, fractures, physical disability, and death[1]. According to the pathogenesis of sarcopenia, sarcopenia can be divided into primary sarcopenia and secondary sarcopenia. Primary sarcopenia is the loss of muscle mass and the decline of muscle function related to aging. Secondary sarcopenia (or disease-related sarcopenia) mainly focuses on the loss of muscle mass and can be secondary to systemic diseases, especially diseases that may trigger inflammatory processes, such as cancer, chronic obstructive pulmonary disease, heart failure, and chronic liver disease[1]. Due to sedentary activities or long-term bed rest related to diseases, this lack of physical activity will concomitantly lead to sarcopenia[2]. In addition, limited energy or insufficient intake of protein due to anorexia, malabsorption, eating ability, and other reasons will also promote the occurrence of sarcopenia. In previous studies, the incidence of sarcopenia in patients with cirrhosis, pancreatic cancer, and primary liver cancer is 40.1%, 38.7%, and 43.2%, respectively[3-5]. Sarcopenia increases the risk of postoperative complications, prolongs hospital stays, and adversely affects prognosis[6].

Obstructive jaundice is a common pathological condition in hepatobiliary and pancreatic diseases, and patients with this condition often experience anorexia and malabsorption causing malnutrition[7]. The previous experimental studies[8] revealed that obstructive jaundice can lead to overall deterioration of the condition of rats, grip strength decreases, and the levels of the inflammatory factors tumor necrosis factor (TNF)-α and interleukin (IL)-6 increase significantly. Furthermore, the expression levels of the proteins atrogin-1 and MuRF1 in muscle tissue also rise significantly. However, the prevalence of sarcopenia in patients with obstructive jaundice and effects of sarcopenia on clinical outcomes remains unclear. The present study aimed to analyze the incidence of surgical obstructive jaundice-related sarcopenia, explore the correlation between severity of jaundice and muscle status, assess the association of sarcopenia on the patients’ clinical outcomes, and provide further evidence to improve patients’ quality of life.

MATERIALS AND METHODS

Ethics statement

The research protocol adhered to every provision of the Helsinki Declaration and received approval from the Research Ethics Committee of the Binzhou Medical University Hospital (Approval No. KYLL-264).

Study design and patients

This cross-sectional study was conducted from December 2019 to January 2024, and included 1708 patients hospitalized in the Department of Hepatobiliary Surgery at a tertiary hospital in Shandong Province, China. While a longitudinal or prospective cohort design incorporating survival data (e.g., cox regression modeling with overall survival as the outcome) would have been more appropriate to assess the long-term prognostic impact of sarcopenia, such follow-up data, were not available for the present cross-sectional analysis. Given the study’s primary aim to investigate the association between obstructive jaundice and sarcopenia prevalence and its related functional and nutritional parameters at the time of admission, a cross-sectional design was selected to efficiently characterize this relationship in a large inpatient cohort.

The inclusion criteria were as follows: (1) Aged ≥ 20 years; (2) Diagnosis of gastrointestinal tumors, hepatobiliary tumors, pancreatic tumors, biliary stones, cholangitis, cholecystitis, pancreatitis, or other abdominal surgical diseases requiring hospitalization; without an operation within the previous 6 months; and (3) Able to complete the sarcopenia diagnostic test; and voluntary participation in this study.

The exclusion criteria were as follows: (1) The presence of muscle-related diseases, such as myasthenia gravis, which could affect grip strength determination; (2) A history of stroke, motor neuron disease, or other conditions that could impair the ability to complete the 6-meter walking test; (3) Implantation of cardiac pacemakers or metal stents that could affect bioelectrical impedance analysis; and (4) Acute onset or severe illness and amputation.

Data collection

Patient demographics were obtained from electronic medical records. Data included age, sex, clinical and pathological diagnoses, and nutritional risk screening status according to the Nutritional Risk Screening 2002 (NRS 2002)[9]. Laboratory data included hemoglobin (Hb) level, lymphocyte counts (LY), albumin (Alb) level, prognostic nutritional index (PNI), and total bilirubin (TBIL) level. The severity of jaundice was classified as follows: Non-jaundiced for patients with a TBIL level ≤ 34.2 μmol/L, mild jaundice for those with TBIL level > 34.2-85 μmol/L, moderate jaundice for those with TBIL level > 85-171 μmol/L, severe jaundice for those with TBIL level > 171-340 μmol/L, and extremely severe jaundice for those with TBIL level > 340 μmol/L. These cutoff values were determined based on clinical definitions used in previous literature, such as mild obstructive jaundice defined as TBIL < 171 μmol/L and recommended lower thresholds for preoperative biliary drainage at 34-51 μmol/L[10,11]. Given the wide TBIL range (34.2-171 μmol/L) and potential clinical heterogeneity within this span, the interval was further subdivided using the distribution characteristics of the collected TBIL data in this study cohort[10-12], allowing for a more granular classification tailored to our population and research objectives.

Clinical measurements included body weight and height, body mass index (BMI), appendicular skeletal muscle index (ASMI), phase angle (PhA), grip strength, walking speed, and the presence or absence of sarcopenia. The skeletal muscle mass and PhA of the limbs were measured using an impedance instrument (InBody S10, Biospace, Korea). ASMI values were calculated using the limb skeletal muscle mass (kg) divided by height (m²). According to the 2019 Asian Working Group for Sarcopenia (AWGS) expert consensus[13], an abnormal ASMI was defined as < 7.0 kg/m² for male patients and < 5.7 kg/m² for female patients. AWGS criteria were selected for their validation in Asian populations, aligning with our cohort’s ethnicity. Cutoffs (e.g., ASMI < 7.0 kg/m² for males by bioelectric impedance analysis) differ from Western standards (e.g., European Working Group on Sarcopenia in Older People’s < 8.87 kg/m²) but improve clinical relevance in this population. According to the Kyle[14] standard, a PhA of < 5.0° for male patients and < 4.6° for female patients was considered abnormal when bioreactance was measured at 50 kHz.

Grip strength was measured using a Jamar dynamometer, and the average of three measurements of the dominant hand was recorded as the grip strength. Patients' physical activity was evaluated using a 6-step speed test, and the two measurements were averaged. The diagnosis of sarcopenia was based on the 2019 AWGS expert consensus[13]: (1) ASMI of < 7.0 kg/m² for males and < 5.7 kg/m² for females based on measurements using the bioresistive method; (2) Grip strength of < 28 kg for male patients and < 18 kg for female patients; and (3) 6-m walking speed < 1 m/s. Sarcopenia was diagnosed if criteria (1) and (2) or (1) and (3) were met. Grip strength measurements were obtained at the time of admission to the hospital prior to any surgical intervention or preoperative optimization procedures such as biliary drainage. This timing was chosen to reflect patients’ baseline functional status upon presentation. However, it is important to acknowledge that acute conditions associated with obstructive jaundice, such as cholangitis and septic shock, may transiently impair grip strength due to hemodynamic instability and systemic inflammation. As a result, patients presenting with jaundice secondary to conditions such as choledocholithiasis with cholangitis may demonstrate temporarily reduced muscle strength compared to those with noninfectious biliary obstruction. This represents a potential confounding factor that was not adjusted for in the current analysis and should be considered when interpreting the association between jaundice severity and sarcopenia prevalence.

For patients undergoing surgical treatment, surgical methods, postoperative hospitalization duration and total length of stay, hospital costs, and postoperative complications were obtained. The postoperative complications were graded according to the Clavien-Dindo complication grading criteria[15]. Although data on surgical method, complication grading, and length of stay were collected, this study did not assess sarcopenia’s association with postoperative reoperation rates or time to reoperation. These indicators, which reflect longer-term or more severe surgical complications, warrant further investigation in future prospective studies aimed at clarifying the clinical consequences of preoperative sarcopenia. In this study, postoperative complications were stratified using the Clavien-Dindo classification system, which enabled us to preliminarily examine whether sarcopenia was associated with not only the overall incidence but also the severity of postoperative complications. However, due to the cross-sectional nature of the study and limited follow-up, reoperation rates and time to reoperation could not be evaluated. In particular, the Clavien-Dindo classification enabled the stratification of postoperative complications by severity, ranging from minor deviations requiring pharmacological intervention (Grade I-II) to life-threatening complications requiring intensive care unit management or reoperation (Grade III-V). This enabled us to preliminarily explore whether sarcopenia was associated with a higher overall rate of complications and increased severity.

Statistical analyses

The statistical methods of this study were reviewed by Wen-Tao Zhu from the Biostatistics Review Committee, Binzhou Medical University Hospital, Binzhou 256603, Shandong Province, China.

The measurement data were expressed as mean ± SD. For data conforming to a normal distribution, a t-test for two independent samples was used for comparisons between two groups, while single-factor analysis of variance was applied for comparisons among multiple groups. For data that did not conform to a normal distribution, the Mann-Whitney U test was used for comparisons between two groups, and the Kruskal-Wallis rank sum test was employed for comparisons among multiple groups. Count data were expressed as numbers of patients or percentages. The χ² test was used for comparisons between unordered counts, and a rank sum test was applied for ordered counts.

A logistic regression model was used to analyze the relationships between obstructive jaundice, sarcopenia, and related indicators, as well as to examine the factors influencing the occurrence of sarcopenia in patients with obstructive jaundice. The confounding factors beyond those listed in the logistic regression model (for example comorbidities such as diabetes or chronic liver disease) have not been adjusted. Spearman’s correlation analysis was conducted on the TBIL level and other parameters in patients with jaundice, and receiver operating characteristic (ROC) curve analysis was performed to evaluate the optimal TBIL level threshold for diagnosing sarcopenia and its diagnostic variables. The optimal TBIL cutoff for sarcopenia diagnosis was determined by maximizing Youden’s index (sensitivity [Se]+ specificity [Sp]−1), which balances the trade-off between identifying true positives and avoiding false positives. All statistical analyses were performed using SPSS software (version 26.0; IBM Corp., Armonk, NY, United States), with P < 0.05 considered to represent statistical significance.

RESULTS

Basic patient information

A total of 1708 patients met the inclusion criteria, with a mean age of 60.09 ± 13.52 years (sex: 52.28% male). The causes of obstructive jaundice included bile duct stone obstruction, inflammation of the bile duct and peribiliary structures, and compression by benign or malignant extrinsic tumors. There were 383 patients (22.42%) with obstructive jaundice and 1325 patients (77.58%) without jaundice. The age of the obstructive jaundice group was significantly higher than that of the non-jaundice group (62.04 ± 13.18 years old vs 59.49 ± 13.59 years old, P < 0.05). Of the patients with jaundice, 196 had benign diseases (51.2%) and 187 had malignant diseases (48.8%). Among the non-jaundiced patients, 883 had benign diseases (66.6%) and 442 had malignant diseases (33.4%). Compared to the non-jaundice group, the proportion of patients at nutritional risk (NRS 2002 rating ≥ 3[9]) was higher in the obstructive jaundice group, while the BMI; PNI; PhA; and levels of Hb, LY, and Alb were significantly lower (P < 0.05, Table 1).

Table 1 Distribution of diseases in jaundice and non-jaundice patients, mean ± SD/n (%).

Parameters	Jaundice (n = 383)	Non-jaundice (n = 1325)	t/χ2	P value
Age	62.04 ± 13.18	59.49 ± 13.59	-3.220	0.001
Sex			30.766	< 0.001
Male	248 (64.7)	645 (48.7)
Female	135 (35.3)	680 (51.3)
Disease			30.551	< 0.001
Benign diseases	196 (51.2)	883 (66.6)
Biliary tract disease	126 (32.9)	692 (52.2)
Liver disease	42 (11.0)	54 (4.1)
Pancreatitis	6 (1.6)	89 (6.7)
Other benign diseases	22 (5.7)	48 (3.6)
Malignant diseases	187 (48.8)	442 (33.4)
Biliary tract tumors	88 (23.0)	56 (4.2)
Liver tumors	49 (12.8)	201 (15.2)
Pancreatic tumors	26 (6.8)	57 (4.3)
Others malignant diseases	24 (6.2)	128 (9.7)
Nutritional risks	181 (47.3)	369 (27.8)	51.269	< 0.001
BMI	23.89 ± 4.17	24.77 ± 9.86	-3.163	0.002
PhA	5.12 ± 1.14	5.37 ± 0.99	-3.974	< 0.001
Hb	124.30 ± 24.07	129.62 ± 20.42	-4.572	< 0.001
LY	1.21 ± 0.67	1.65 ± 1.61	-10.593	< 0.001
Alb	36.38 ± 6.38	39.64 ± 5.73	-9.918	< 0.001
PNI	42.45 ± 7.28	47.91 ± 9.85	-12.224	< 0.001

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index.

Prevalence and related indicators of sarcopenia in patients with obstructive jaundice

The incidence of sarcopenia in the obstructive jaundice group was higher than in the nonobstructive jaundice group (28.2% vs 18.9%, P < 0.05). Slow walking speed (35.0% vs 22.1%), decreased grip strength (42.8% vs 27.2%), and lower ASMI values (37.9% vs 31.0%) were more prevalent in those with obstructive jaundice (P < 0.05, Table 2).

Table 2 Comparison of sarcopenia and diagnostic indexes in patients with jaundice and non-jaundice, n (%).

Parameters	Jaundice (n = 383)	Non-jaundice (n = 1325)	t/χ2	P value
Slow pace	134 (35.0)	293 (22.1)	26.262	< 0.001
Decreased grip strength	164 (42.8)	361 (27.2)	33.852	< 0.001
Lower ASMI	145 (37.9)	411 (31.0)	6.331	0.012
SC	108 (28.2)	250 (18.9)	15.613	< 0.001

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia.

Comparison of sarcopenia in patients with obstructive jaundice due to different diseases

A total of 383 patients were divided into groups according to the potential causes of obstructive jaundice, including the bile duct diseases group, pancreatic diseases group, liver diseases group, and other conditions. Among these patients, the proportion of sarcopenia in those with liver diseases was 9.9%, significantly lower than that observed in patients with bile duct diseases (33.2%), pancreatic diseases (59.4%), and other diseases (37.0%) (P < 0.05). Furthermore, the proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was statistically significantly lower than that in the other disease categories (P < 0.05, Table 3).

Table 3 Incidence of sarcopenia in obstructive jaundice by etiology, mean ± SD/n (%).

Parameters	Bile duct diseases (n = 241)	Pancreatic diseases (n = 32)	Liver diseases (n = 91)	Other diseases (n = 46)	F/χ2	P value
Age	63.89 ± 13.09	63.78 ± 10.73	55.98 ± 12.85a	63.74 ± 13.35c	25.660	< 0.001
Sex					7.730
Male	137 (64.0)	15 (46.9)	67 (73.6)	29 (63.0)
Female	77 (36.0)	17 (53.1)	24 (26.4)	17 (37.0)
Slow pace	87 (40.7)	14 (43.8)	15 (16.5)d,e,f	18 (39.1)	18.147	< 0.001
Decreased grip strength	107 (50.0)	13 (40.6)	22 (24.2)j,k	22 (47.8)	17.959	< 0.001
Lower ASMI	88 (41.1)	19 (59.4)	18 (19.8)g,h,i	20 (43.5)	20.525	< 0.001
SC	71 (33.2)	11 (34.4)	9 (9.9)a,b,c	17 (37.0)	20.031	< 0.001

^aP < 0.05. The proportion of sarcopenia with liver diseases was lower than in patients with bile duct diseases, pancreatic diseases, and other diseases.

^bP < 0.05. The proportion of sarcopenia with liver diseases was lower than in patients with bile duct diseases, pancreatic diseases, and other diseases.

^cP < 0.05. The proportion of sarcopenia with liver diseases was lower than in patients with bile duct diseases, pancreatic diseases, and other diseases.

^dP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

^eP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

^fP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

^gP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

^hP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

ⁱP < 0.05. The proportion of patients with liver disease who exhibited slow walking speed and lower ASMI values was lower than that in patients with bile duct diseases, pancreatic diseases, and other diseases.

^jP < 0.05. The proportion of patients with liver disease who exhibited decreased grip strength was lower than in patients with bile duct diseases and other diseases.

^kP < 0.05. The proportion of patients with liver disease who exhibited decreased grip strength was lower than in patients with bile duct diseases and other diseases.

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia.

The population of 383 patients with jaundice was further divided into benign (n = 196) and malignant (n = 187) jaundice groups. The incidence of sarcopenia was higher in the malignant group than in the benign group (33.2% vs 23.5%, P < 0.05). The proportions of slow walking speed (43.9% vs 26.5%), lower grip strength (49.2% vs 36.7%), and lower ASMI (44.4% vs 31.6%) were also higher in those with malignant jaundice (P < 0.05, Table 4). Although sarcopenia, slow walking speed, reduced grip strength, and lower ASMI values were more prevalent in patients with malignant jaundice than in those with benign jaundice (P < 0.05), malignancy was not identified as an independent risk factor for sarcopenia in multivariate logistic regression analysis.

Table 4 Comparison of sarcopenia and diagnostic indicators in benign and malignant jaundice patients, mean ± SD/n (%).

Parameters	Malignant jaundice (n = 187)	Benign jaundice (n = 196)	t/χ2	P value
Age	65.54 ± 10.11	58.69 ± 14.84	-4.633	< 0.001
Sex			0.389
Male	124 (66.3)	124 (63.3)
Female	63 (33.7)	72 (36.7)
Slow pace	82 (43.9)	52 (26.5)	12.620	< 0.001
Decreased grip strength	92 (49.2)	72 (36.7)	6.071	0.014
Lower ASMI	83 (44.4)	62 (31.6)	6.615	0.010
SC	62 (33.2)	46 (23.5)	4.434	0.035

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia.

Comparison of sarcopenia prevalence in patients by severity of jaundice

In comparing the sarcopenia status of patients with mild, moderate, severe, and extremely severe jaundice, the incidence of sarcopenia was higher in the severe jaundice group than in the mild jaundice group (39.3% vs 22.8%, P < 0.05). When analyzing walking speed, grip strength, and ASMI values across these groups, 46.1% of patients with severe jaundice exhibited slow walking, a higher proportion than those in the mild (27.5%) and moderate (26.1%) jaundice groups (P < 0.05). Additionally, 55.1% of patients with severe jaundice had decreased grip strength, a higher proportion than observed in the moderate jaundice group (30.7%) (P < 0.05). Similarly, 51.7% of patients with severe jaundice had lower ASMI values, exceeding the proportions seen in the mild (32.9%) and moderate (29.5%) jaundice groups, with statistically significant differences (P < 0.05). Furthermore, 61.5% of patients with extremely severe jaundice have a higher rate of walking slowly than those with mild and moderate jaundice (P < 0.05). Moreover, 56.4% of patients with extremely severe jaundice had decreased grip strength, a higher proportion than that seen in the moderate jaundice group (P < 0.05, Table 5).

Table 5 Comparison of sarcopenia incidence according to different degrees of obstructive jaundice, mean ± SD/n (%).

Parameters	Mild (n = 167)	Moderate (n = 88)	Severe (n = 89)	Extremely severe (n = 39)	F/χ2	P value
Age	60.16 ± 13.67	59.61 ± 12.43	65.96 ± 12.47a,b	66.08 ± 11.26a,b	22.192	< 0.001
Sex					5.940
Male	119 (71.3)	51 (58.0)	53 (59.6)	25 (64.1)
Female	48 (28.7)	37 (42.0)	36 (40.4)	14 (35.9)
Slow pace	46 (27.5)	23 (26.1)	41 (46.1)b,c	24 (61.5)g,h	23.988	<0.001
Decreased grip strength	66 (39.5)	27 (30.7)	49 (55.1)d	22 (56.4)i	14.384	0.002
Lower ASMI	55 (32.9)	26 (29.5)	46 (51.7)e,f	18 (46.2)	12.647	0.005
SC	38 (22.8)	19 (21.6)	35 (39.3)a	16 (41.0)	12.954	0.005

^aP < 0.05. The incidence of sarcopenia was higher in the severe jaundice group than in the mild jaundice group.

^bP < 0.05. Severe jaundice exhibited slow walking was higher than those in the mild and moderate jaundice groups.

^cP < 0.05. Severe jaundice exhibited slow walking was higher than those in the mild and moderate jaundice groups.

^dP < 0.05. Patients with severe jaundice had decreased grip strength was higher than in the moderate jaundice group.

^eP < 0.05. Severe jaundice had lower ASMI value was higher than in the mild and moderate jaundice groups.

^fP < 0.05. Severe jaundice had lower ASMI value was higher than in the mild and moderate jaundice groups.

^gP < 0.05. Patients with extremely severe jaundice have a higher rate of walking slowly than those with mild and moderate jaundice.

^hP < 0.05. Patients with extremely severe jaundice have a higher rate of walking slowly than those with mild and moderate jaundice.

ⁱP < 0.05. Patients with extremely severe jaundice had decreased grip strength was higher than that seen in the moderate jaundice group.

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia.

Correlation analysis between TBIL level and sarcopenia-related variables

Spearman’s correlation was used to analyze the relationship between TBIL levels and other indices in the 383 patients with jaundice. The results showed that TBIL levels were negatively correlated with ASMI values, grip strength, and PhA, and positively correlated with sarcopenia, slow gait, and NRS2002 Levels (P < 0.05, Table 6).

Table 6 Correlation analysis between total bilirubin level and each index.

Parameters	Lower ASMI	Decreased grip strength	SC	Slow pace	PhA	Nutritional risks
r	-0.125	-0.152	0.126	0.202	-0.178	0.214
P value	0.014	0.003	0.014	< 0.001	< 0.001	< 0.001

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia; PhA: Phase angle.

ROC curve analysis was employed to evaluate the optimal critical TBIL value for diagnosing sarcopenia and its diagnostic indicators. The predicted critical TBIL value was 174.2 μmol/L for sarcopenia and 174.2 μmol/L for male sarcopenia (Se = 0.747, Sp = 0.484). For female patients, the value was 147.8 μmol/L (Se = 0.629, Sp = 0.544). The optimal TBIL threshold for diagnosing lower ASMI values was 173.4 μmol/L, whereas the optimal threshold for predicting lower ASMI was 168.9 μmol/L (Se = 0.738, Sp = 0.409) in male patients, and 217.6 μmol/L (Se = 0.808, Sp = 0.456) in female patients. The optimal TBIL critical value for predicting grip strength loss was 176.9 μmol/L, with 174.2 μmol/L for male patients (SEN = 0.784, SPEC = 0.463) and 335.7 μmol/L for female patients (SEN = 0.924, SPEC = 0.174). The best TBIL critical value for predicting slow gait was 178.4 μmol/L, with 184.5 μmol/L for males (SEN = 0.796, SPEC = 0.472) and 147.8 μmol/L for females (SEN = 0.671, SPEC = 0.548).

The analysis indicates that TBIL levels have a certain predictive ability for diagnosing sarcopenia, lower ASMI, grip strength loss, and slow gait in patients with obstructive jaundice (Figure 1). The area under the curve (AUC) values for TBIL in diagnosing sarcopenia, lower ASMI, lower grip strength, and slow gait ranged from 0.56 to 0.63 (Figure 1). Although these AUC values are greater than 0.5, indicating a statistically significant association (P < 0.05), the modest AUCs suggest limited discriminative power for individual biomarkers. For instance, a TBIL level greater than 174.2 μmol/L in males achieved a sensitivity of 74.7% but a specificity of only 48.4%, highlighting its utility as a screening tool rather than a definitive diagnostic criterion.

Figure 1 Receiver operating characteristic curve for total bilirubin in diagnosing sarcopenia and its diagnostic indicators. A: Curve for total bilirubin (TBIL) in diagnosing sarcopenia; B: Curve for TBIL in diagnosing low appendicular skeletal muscle index; C: Curve for TBIL in diagnosing low grip strength; D: Curve for TBIL in diagnosing slow pace. AUC: Area under curve; ASMI: Appendicular skeletal muscle index.

Logistic regression analysis of obstructive jaundice and sarcopenia and related indicators

As shown in Table 2, differences were noted in the incidence of sarcopenia between the obstructive jaundice and nonobstructive jaundice groups, as well as in the comparison of walking speed, grip strength, and limb muscle mass as diagnostic indicators of sarcopenia. The presence or absence of jaundice was designated as the dependent variable, whereas the presence or absence of sarcopenia, slower walking speed, lower grip strength, and lower ASMI values were considered independent variables in the univariate logistic regression analysis. The results indicated that the occurrence of jaundice in patients correlated with the presence of sarcopenia, slower walking speed, lower grip strength, and decreased muscle mass (P < 0.05). The presence or absence of jaundice remained the dependent variable, with sarcopenia, slow gait, decreased grip strength, and lower ASMI values as independent variables. Differences in age; sex; nutritional risk; BMI; PNI; PhA; and levels of Hb, LY, and Alb were included as confounders, and a multivariate logistic regression analysis was performed. The results demonstrated that jaundice increases the risk of slow walking, with statistical significance [odds ratio (OR) = 1.627, 95% confidence interval (CI): 1.185-2.234, P < 0.05]. Jaundice also significantly increased the risk of decreased grip strength in patients (OR = 1.669, 95%CI: 1.212-2.300, P < 0.05). These findings suggest that obstructive jaundice is an independent risk factor for slow walking and reduced grip strength (Table 7).

Table 7 Logistic regression analysis of obstructive jaundice, sarcopenia, and related indicators.

Parameters	Single-factor regression analysis		Multivariate regression analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Slow pace	1.895 (1.481, 2.426)	< 0.001	1.627 (1.185, 2.234)	0.003
Decreased grip strength	1.950 (1.540, 2.469)	< 0.001	1.669 (1.212, 2.300)	0.002
Lower ASMI	1.355 (1.069, 1.717)	0.012	1.035 (0.677, 1.582)
SC	1.689 (1.300, 2.194)	< 0.001	1.014 (0.979, 1.050)

ASMI: Appendicular skeletal muscle index; SC: Sarcopenia.

Analysis of sarcopenia-related factors in patients with obstructive jaundice

Comparison between the obstructive jaundice group and nonobstructive jaundice group: A total of 383 patients with obstructive jaundice were divided into two groups based on whether the condition was complicated by sarcopenia. Patients with obstructive jaundice were older than those in the non-sarcopenia group (70.44 ± 11.20 years old vs 58.71 ± 12.42 years old, P < 0.001), and the incidence of malignant tumors was higher in the sarcopenia group compared to the non-sarcopenia group (57.4% vs 45.5%, P < 0.05). Furthermore, patients with sarcopenia and obstructive jaundice had a higher proportion of nutritional risk and exhibited lower BMI, PhA, PNI, and lower levels of, Hb, LY, and Alb (P < 0.05, Table 8).

Table 8 Comparison between sarcopenia and non-sarcopenia patients with obstructive jaundice, mean ± SD/n (%).

Parameters	SC (n = 108)	Non-SC (n = 275)	t/χ2	P value
Age	70.44 ± 11.20	58.71 ± 12.42	-8.865	< 0.001
Sex			3.555
Male	62 (57.4)	186 (67.6)
Female	46 (42.6)	89 (32.4)
Malignant diseases	62 (57.4)	125 (45.5)	4.434	0.035
Nutritional risks	73 (67.6)	108 (39.3)	24.952	< 0.001
BMI	20.83 ± 2.72	25.11 ± 4.02	-9.712	< 0.001
PhA	4.27 ± 0.84	5.44 ± 1.07	-9.549	< 0.001
Hb	115.76 ± 20.69	127.69 ± 24.50	-4.588	< 0.001
LY	1.12 ± 0.57	1.25 ± 0.70	-1.520
Alb	34.85 ± 6.21	36.99 ± 6.36	-3.349	0.001
PNI	40.45 ± 7.14	43.24 ± 7.19	-3.700	< 0.001

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index; SC: Sarcopenia.

Logistic regression analysis of sarcopenia, slow walking speed, reduced grip strength, and reduced ASMI values in patients with obstructive jaundice

The presence or absence of sarcopenia, slow gait, reduced grip strength, and lower ASMI values were used as dependent variables, whereas age; malignant tumors; nutritional risk; BMI; PhA; PNI; and levels of Hb and Alb were used as independent variables for the univariate logistic regression analysis. The results indicated that increasing age, the presence of cancer, the presence of nutritional risk, low BMI, low PhA, low Hb levels, low Alb levels, and low PNI were associated with sarcopenia, slow gait, and lower grip strength in patients with obstructive jaundice (P < 0.05). Factors associated with a lower ASMI included increasing age, the presence of cancer, nutritional risk, low BMI, low PhA, low Hb level, and low LY level (P < 0.05).

A multivariate logistic regression analysis was performed after adjusting for confounding factors. The results demonstrated that age (OR = 1.077, 95%CI: 1.040-1.114, P < 0.001) and BMI (OR = 0.703, 95%CI: 0.630-0.784, P < 0.001) were risk factors for sarcopenia. With increasing age and decreasing BMI, patients with obstructive jaundice faced an elevated risk of sarcopenia. Increased age (OR = 1.066, 95%CI: 1.035-1.098, P < 0.001), malignant tumors (OR = 1.674, 95%CI: 1.005-2.788, P = 0.048), and decreased PhA (OR = 0.591, 95%CI = 0.419-0.833, P = 0.003) were identified as risk factors for slow walking. Increased age (OR = 1.062, 95%CI: 1.032-1.093, P < 0.001), decreased BMI (OR = 0.902, 95%CI: 0.840-0.969, P = 0.005), and decreased PhA (OR = 0.547, 95%CI: 0.383-0.781, P = 0.001) were risk factors for reduced grip strength. Increased age (OR: 1.048, 95%CI: 1.017-1.079, P = 0.002) and decreased BMI (OR = 0.658, 95%CI: 0.591-0.733, P < 0.001) emerged as risk factors for a lower ASMI (Tables 9, 10, 11, and 12). Although malignancy was significantly associated with sarcopenia-related indicators in univariate analysis, it was not retained as an independent predictor of sarcopenia after adjusting for confounding variables.

Table 9 Logistic regression analysis of sarcopenia in patients with obstructive jaundice.

Parameters	Single-factor regression analysis		Multivariate regression analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Age	1.105 (1.076, 1.135)	< 0.001	1.077 (1.040, 1.114)	< 0.001
Malignant diseases	1.617 (1.032, 2.535)	0.036	0.951 (0.463, 1.565)
Nutritional risks	3.225 (2.016, 5.160)	< 0.001	1.682 (0.906, 3.124)
BMI	0.664 (0.602, 0.734)	< 0.001	0.703 (0.630, 0.784)	< 0.001
PhA	0.311 (0.235, 0.413)	< 0.001	0.706 (0.474, 1.050)
Hb	0.979 (0.969, 0.988)	< 0.001	0.998 (0.983, 1.014)
Alb	0.946 (0.912, 0.982)	0.003	0.994 (0.894, 1.105)
PNI	0.952 (0.923, 0.983)	0.002	1.003 (0.918, 1.095)

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index.

Table 10 Logistic regression analysis of slow walking speed in patients with obstructive jaundice.

Parameters	Single-factor regression analysis		Multivariate regression analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Age	1.101 (1.074, 1.129)	< 0.001	1.066 (1.035, 1.098)	< 0.001
Malignant diseases	2.163 (1.408, 3.321)	< 0.001	1.674 (1.005, 2.788)	0.048
Nutritional risks	2.389 (1.554, 3.674)	< 0.001	1.186 (0.710, 1.979)
BMI	0.907 (0.858, 0.959)	0.001	0.990 (0.926, 1.058)
PhA	0.388 (0.304, 0.496)	< 0.001	0.591 (0.419, 0.833)	0.003
Hb	0.982 (0.973, 0.992)	< 0.001	1.000 (0.987, 1.012)
LY	0.879 (0.634, 1.218)	0.438
Alb	0.947 (0.914, 0.980)	0.002	0.975 (0.894, 1.063)
PNI	0.958 (0.930, 0.987)	0.005	1.013 (0.942, 1.090)

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index.

Table 11 Logistic regression analysis of reduced grip strength in patients with obstructive jaundice.

Parameters	Single-factor regression analysis		Multivariate regression analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Age	1.104 (1.078, 1.131)	< 0.001	1.062 (1.032, 1.093)	< 0.001
Malignant diseases	1.668 (1.109, 2.508)	0.014	0.988 (0.586, 1.667)
Nutritional risks	3.052 (2.005, 4.648)	< 0.001	1.566 (0.932, 2.631)	0.090
BMI	0.837 (0.788, 0.889)	< 0.001	0.902 (0.840, 0.969)	0.005
PhA	0.291 (0.221, 0.383)	< 0.001	0.547 (0.383, 0.781)	0.001
Hb	0.978 (0.969, 0.987)	< 0.001	1.001 (0.988, 1.013)
LY	0.778 (0.565, 1.071)	0.124
Alb	0.923 (0.891, 0.956)	< 0.001	0.970 (0.888, 1.059)
PNI	0.938 (0.911, 0.967)	< 0.001	0.992 (0.921, 1.069)

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index.

Table 12 Logistic regression analysis of appendicular skeletal muscle index reductions in patients with obstructive jaundice.

Parameters	Single-factor regression analysis		Multivariate regression analysis
	OR (95%CI)	P value	OR (95%CI)	P value
Age	1.070 (1.048, 1.092)	< 0.001	1.048 (1.017, 1.079)	0.002
Malignant diseases	1.725 (1.137, 2.617)	0.010	0.916 (0.517, 1.623)
Nutritional risks	2.771 (1.809, 4.246)	< 0.001	1.765 (0.990, 3.147)	0.054
BMI	0.632 (0.572, 0.698)	< 0.001	0.658 (0.591, 0.733)	< 0.001
PhA	0.386 (0.303, 0.492)	< 0.001	0.763 (0.533, 1.091)
Hb	0.983 (0.974, 0.992)	< 0.001	1.005 (0.992, 1.019)
LY	0.670 (0.473, 0.948)	0.024	0.858 (0.561, 1.314)
Alb	0.983 (0.951, 1.016)	0.302
PNI	0.976 (0.949, 1.004)	0.089

BMI: Body mass index; PhA: Phase angle; Hb: Hemoglobin; LY: Lymphocyte count; Alb: Albumin; PNI: Prognostic nutritional index.

Effects of sarcopenia on postoperative outcomes in patients with obstructive jaundice

Among 263 patients with obstructive jaundice who underwent abdominal operations, the sarcopenia group (n = 82) had a significantly longer postoperative hospital stay than the non-sarcopenia group (11.33 ± 6.75 days vs 9.19 ± 7.32 days, P = 0.016), as well as a longer total hospital stay (17.10 ± 7.69 days vs 15.98 ± 8.55 days, P = 0.032). The complication rate was also higher in the sarcopenia group (46.3% vs 33.1%, P = 0.032), with a greater incidence of postoperative grade I and II complications (42.7% vs 17.6%, P = 0.016). Notably, a higher proportion of patients in the sarcopenia group had malignant disease (57.4% vs 45.5%, P < 0.05), which might independently contribute to poorer outcomes. Additionally, differences in the type and extent of procedure (e.g., pancreaticoduodenectomy vs. cholecystectomy) were not controlled for in this analysis and might have also influenced postoperative stay and complications. These potential confounders limit the ability to attribute differences solely to sarcopenia (Table 13). As summarized in Table 13, patients with sarcopenia experienced a higher proportion of Grade III or higher complications than those without sarcopenia, suggesting that sarcopenia may predispose individuals to more severe postoperative courses. However, given the cross-sectional design, causality cannot be established, and these findings warrant validation in a prospective cohort. Although the Clavien-Dindo classification was used to grade postoperative complications, this study did not perform a detailed stratified analysis comparing the distribution of complication grades between patients with and without sarcopenia. Moreover, data on reoperation rates and time to reoperation were not available for analysis in this cohort.

Table 13 Influence of related sarcopenia on postoperative clinical outcomes in patients with obstructive jaundice, mean ± SD/n (%).

Parameters	SC (n = 82)	Non-SC (n = 181)	t/χ2	P value
Hospitalization expenses	36917.59 ± 21297.73	34662.17 ± 22760.28	-0.676
Postoperative hospital stay	11.33 ± 6.75	9.19 ± 7.32	-2.431	0.016
Total hospital stay	17.10 ± 7.69	15.98 ± 8.55	-1.887	0.032
Occurrence of postoperative complications	38 (46.3)	60 (33.1)	4.201	0.040
Clavien-Dindo Classification
Grade I, II	35 (42.7)	50 (17.6)	5.850	0.016
Grade Ⅲ and above	3 (3.6)	10 (5.5)	0.418

SC: Sarcopenia.

DISCUSSION

Obstructive jaundice is a common pathophysiological condition caused by hepatobiliary and pancreatic diseases, which severely impair the functions of various tissues and organs in the body. This includes liver dysfunction, renal dysfunction, intestinal barrier dysfunction, endotoxemia, malnutrition, and reduced immune function[16]. This study found that the incidence of sarcopenia in patients with obstructive jaundice was as high as 28.2%, significantly greater than the 17.4% observed in older community-dwelling adults[17] and 14.59% observed in patients undergoing abdominal operations[18]. We further examined gait speed, grip strength, and ASMI as indicators of muscle function and found that these measures were significantly lower in patients with jaundice than in those without jaundice. Recent studies have suggested that prehabilitation may improve functional and postoperative outcomes in colorectal surgery patients; however, its efficacy in hepatopancreatobiliary procedures remains unclear[19]. The high prevalence of sarcopenia and malnutrition observed in patients with obstructive jaundice in our cohort, along with their increased risk of postoperative complications, raises the question of whether the diminished benefit of prehabilitation in hepato-pancreato-biliary surgery may be partly attributable to the pathophysiological burden of obstructive jaundice, including cholestasis-related systemic inflammation, impaired nutritional absorption, and hepatic dysfunction. Further studies are needed to evaluate whether targeted prehabilitation protocols adapted to obstructive jaundice-specific constraints might yield improved outcomes in this population.

In an animal model experiment, Wang[8] demonstrated that in rats with obstructive jaundice, the gastrocnemius muscle fibers exhibited disorganization and distortion. The muscle fibers showed signs of atrophy, fractures, and variations in size and shape. Muscle cell spacing increased, muscle fibers exhibited slight autolysis, the fiber bundle membrane displayed minor breaks, and the wet weight of the gastrocnemius muscle was significantly reduced. Grip strength in these rats was also decreased. Therefore, obstructive jaundice can lead to abnormalities in muscle structure and function.

In this study, the effects of various causes of obstructive jaundice on muscles were analyzed. While sarcopenia and its related indicators were more prevalent among patients with malignant jaundice in univariate analysis, malignancy was not an independent risk factor for sarcopenia after adjusting for age, nutritional status, and other confounders. This demonstrates that the increased sarcopenia burden in patients with malignancy may be attributable to underlying factors, such as age and malnutrition rather than malignancy itself. Patients with severe and extremely severe jaundice exhibited higher rates of sarcopenia, slower walking speeds, lower grip strength, and reduced lower limb muscle mass compared to those with mild-to-moderate jaundice. After adjusting for confounders, jaundice was identified as an independent risk factor for slow walking speed and reduced grip strength. Thus, we believe that the severity of jaundice and TBIL levels significantly influence muscle function in patients. The more severe the jaundice, the higher the TBIL level, and the greater the likelihood of sarcopenia development. The stratification of jaundice severity in this study was based on clinically recognized TBIL thresholds derived from prior literature, including definitions for mild obstructive jaundice and recommendations for preoperative biliary drainage interventions. However, the TBIL range of 34.2-171 μmol/L includes a broad spectrum of clinical heterogeneity. To address this heterogeneity, we further subdivided this range into mild, moderate, and severe categories based on data distribution within our cohort. This granular stratification enabled a more nuanced analysis of the association between bilirubin burden and sarcopenia-related indicators. The findings of the present study indicated a stepwise increase in sarcopenia prevalence and its components (e.g., reduced grip strength, low ASMI, slow gait) with increasing TBIL levels. This highlights the clinical utility of bilirubin stratification in identifying patients at higher risk for muscle dysfunction. Notably, these cutoff values may not universally generalize across populations or clinical settings. Alternative stratification schemes, such as those based on disease-specific thresholds or dynamic changes in TBIL, might yield different associations. Future studies are warranted to validate our TBIL categories and explore whether continuous TBIL modeling might provide improved predictive accuracy for sarcopenia risk. In addition, our ROC curve analysis demonstrated the predictive value of TBIL levels for sarcopenia. When TBIL was between 173.4 μmol/L and 178.4 μmol/L, patients undergoing hepatobiliary and pancreatic procedures were more likely to experience sarcopenia, slower walking speeds, lower grip strength, and diminished lower limb muscle mass, coinciding with TBIL levels indicative of severe jaundice. This confirms the effect of the degree of jaundice on the occurrence of sarcopenia. The modest AUC values (0.56-0.63) observed in our ROC analyses imply that isolated biomarkers like TBIL level may have limited standalone diagnostic accuracy for sarcopenia, several factors may have contributed to the modest AUC values in our study. First, the heterogeneity of obstructive jaundice etiologies (e.g., benign vs. malignant) could introduce variability in TBIL’s relationship with sarcopenia. Second, single-biomarker models inherently lack the complexity needed to capture multifactorial conditions like sarcopenia. Finally, potential measurement errors in TBIL assays or sarcopenia diagnostics (e.g., bioelectrical impedance variability) might attenuate observed associations, Future studies should validate these thresholds in multicenter cohorts and explore integrated models combining TBIL level with inflammatory markers or nutritional indices (e.g., PNI) to enhance diagnostic accuracy. Among patients with benign obstructive jaundice, the etiology may include conditions such as choledocholithiasis, choledochal cysts, or large hepatic cysts, which typically require less extensive procedures than malignant causes. These differences in surgical invasiveness and perioperative nutritional impact may partially explain the lower prevalence of sarcopenia in the benign group. Future subgroup analyses focusing on specific benign etiologies may help delineate these effects more precisely.

In this study, we examined the effects of age, disease type, nutritional risk, BMI, PhA, Hb levels, Alb levels, PNI, and other factors on obstructive jaundice-related sarcopenia. We found that the occurrence of sarcopenia was positively correlated with age and negatively correlated with BMI. Similarly, Merchant et al[20] reported that a higher BMI was associated with a lower prevalence of sarcopenia and provided a protective effect against its occurrence. Subsequently, we conducted logistic analysis on the three diagnostic indicators of sarcopenia-walking speed, grip strength, and ASMI-and found that age, BMI, primary disease, and PhA impacted these indicators, thereby affecting the incidence of sarcopenia. As an important parameter in bioelectrical impedance analysis, PhA has been shown to correlate with a higher prevalence of sarcopenia in patients with low PhA, reflecting the body's fluid and nutritional status more reliably[21]. Overall, the statistical results of this study align with those of previous studies, providing new evidence for the role of PhA in assessing muscle status.

As a heterogeneous symptom, obstructive jaundice's basic diagnosis may not be clear at admission. Obstructive jaundice contributes to malnutrition through reduced food intake and impaired fat absorption, which can indirectly affect patients’ overall condition[22,23]. Although the direct mechanisms linking obstructive jaundice to muscle wasting are underexplored, several pathological processes may promote sarcopenia[24]. Chronic systemic inflammation associated with obstructive jaundice can disrupt muscle protein metabolism. Bile duct obstruction alters intestinal microbiota and increases endotoxin absorption, stimulating cytokine production (e.g., TNF-α, IL-6), which activates proteolytic pathways, such as the ubiquitin-proteasome system and autophagy, promoting muscle degradation[25,26]. In addition, elevated bile acids with cholestasis impair mitochondrial function via the TGR5 receptor, reducing ATP synthesis in the muscle fibers[27]. Obstructive jaundice also disrupts fat and fat-soluble vitamin absorption, particularly vitamin D, which is essential for muscle strength. Vitamin D deficiency and dysfunction of the vitamin D/VDR axis further contribute to sarcopenia through multiple mechanisms, involving proteolysis, mitochondrial dysfunction, cellular aging, and adiposity.

Sarcopenia increases the risk of falls, disability, frailty, and death in the community, while also reducing quality of life. Recent studies have found that disease-associated sarcopenia adversely affects the treatment and prognosis of the primary disease. Furthermore, several studies[28-30] indicated that sarcopenia can lead to negative postoperative outcomes, prolong hospital stays, and reduce long-term survival in patients undergoing abdominal operations. For instance, Zhang et al[31] demonstrated that the rates of postoperative pneumonia, pancreatic leakage, and mortality in sarcopenic patients undergoing pancreaticoduodenectomy were significantly higher than in those without sarcopenia. Additionally, Zhang et al[32] found that sarcopenia increases the incidence of complications after hepatectomy in patients with liver cancer, extends the length of hospital stays, and shortens overall survival. In this study, it was observed that both postoperative and total hospital stays were prolonged, and the incidence of postoperative complications increased in patients with sarcopenia. These findings revealed that sarcopenia impacts adverse outcomes of surgical treatment in patients with obstructive jaundice. It is consistent with the previous study findings of our research group[18].

Clinical attention should be directed toward patients with obstructive jaundice who also have sarcopenia. Preoperative screening should be strengthened, and the Ishii score, Calf Circumference (SARC-Calf) questionnaire[33,34] is a relatively simple screening method. The Ishii score monitors sarcopenia risk in patients using 3 variables: Age, grip strength, and calf circumference. The SARC-Calf questionnaire is a preliminary screening of muscle condition through grip strength, assistance with walking, chair-stand test, climbing stairs, falls, and calf circumference.

Sarcopenia can be diagnosed by measuring muscle mass, muscle strength, and physical performance (such as grip strength and walking speed); performing body composition analysis to calculate ASMI values; and using computed tomography to observe the muscle area at the third lumbar transverse process[14]. For the treatment of sarcopenia, the main intervention measures currently include nutritional supplements and high-protein diets combined with exercise. Specific supplements, such as creatine, beta-hydroxy-beta-methylbutyrate, vitamin D, and essential amino acids, such as leucine[35], may aid in stimulating muscle protein synthesis and repair. In addition, a balanced diet rich in antioxidants and anti-inflammatory nutrients can help reduce inflammation and maintain stable muscle conditions[36]. Wang et al[37] further demonstrated that resistance exercise could significantly improve muscle function in patients. Overall, effective dietary interventions and structured exercise programs can not only improve muscle health in sarcopenic patients but also contribute positively to their clinical outcomes and prognosis. Although malignancy was not identified as an independent risk factor for sarcopenia in our multivariate analysis, patients with malignant obstructive jaundice exhibited higher rates of sarcopenia and its related indicators. This finding aligns with previous studies suggesting that skeletal muscle status, rather than the presence of malignancy per se, may be more clinically informative in guiding prognosis and management. For instance, Zhang et al[38] reported that a low skeletal muscle index predicted poorer survival outcomes in patients undergoing percutaneous transhepatic biliary drainage for malignant perihilar cholangiocarcinoma. These results highlight the potential utility of incorporating muscle-related parameters into clinical decision-making for biliary drainage, especially in patients with malignancy.

There are still limitations in this observational study. Including the single-center design, potential selection bias, and lack of longitudinal data. The observed associations between sarcopenia and adverse postoperative outcomes, including prolonged hospitalization and increased complication rates, must be interpreted with caution. A higher proportion of patients with sarcopenia had underlying malignancy, which itself was associated with worse postoperative recovery. Furthermore, variations in surgical procedures, ranging from relatively minor operations to extensive resections, such as pancreaticoduodenectomy, may have also confounded the relationship between sarcopenia and outcomes. Without adjustment for these factors, the current analysis cannot determine whether sarcopenia is an independent predictor of postoperative morbidity. Although this study collected perioperative clinical data, such as surgical method, complication severity (Clavien-Dindo grading), and postoperative length of stay, in-hospital mortality or perioperative death was not systematically recorded and thus, could not be analyzed in relation to sarcopenia indices. Consequently, it remains unclear from this dataset whether sarcopenia is independently associated with short-term mortality postoperatively. This study did not investigate the impact of sarcopenia on specific postoperative outcomes, such as time to reoperation or reoperation rates, representing important indicators of adverse surgical trajectories. Although the Clavien-Dindo classification system was used to record complication severity, no subgroup analysis was conducted to evaluate its distribution by sarcopenia status. Future prospective studies with longer follow-ups are required to assess the prognostic significance of preoperative sarcopenia on clinically meaningful endpoints, such as reoperation risk and long-term morbidity. Given that severe sarcopenia may reflect profound physiological vulnerability and compromised functional reserve, future studies should evaluate whether it constitutes a risk factor for in-hospital death or adverse perioperative trajectories. Clarifying this association is essential to determine whether sarcopenia should be considered a relative or absolute contraindication to major surgical interventions in patients with obstructive jaundice or other hepatobiliary diseases. Future studies should incorporate multivariate analyses or propensity score matching to better distinguish the effects of sarcopenia from other clinical variables. Future prospective studies are warranted to clarify whether sarcopenia independently predicts overall survival in this population. In addition to overall survival, future studies should evaluate whether sarcopenia is associated with postoperative outcomes such as complication severity, time to reoperation, and reoperation rates. This may help clarify whether sarcopenia contributes not only to baseline vulnerability but also to adverse surgical trajectories in patients with hepatobiliary diseases. Future multicenter studies should validate TBIL level thresholds and explore causality.

CONCLUSION

In summary, the prevalence of sarcopenia in patients with obstructive jaundice is higher than those without jaundice and positively correlates with the degree of jaundice, which is an important factor affecting postoperative adverse outcomes and patient prognosis. Several plausible mechanisms that may explain observed associations between sarcopenia and other health conditions have been proposed, but all require further investigation.

ACKNOWLEDGEMENTS

We are grateful to the doctors and nurses from the Binzhou Medical University Hospital for their active cooperation and assistance during the medical procedures of obtaining research data.