Park HJ, Oh YE, Chi SA, Kim M, Kim JE, Hong SN, Min BH, Kim YH, Chang DK, Kim TS, Kim ER. Impact of glucagon-like peptide-1 receptor agonists on bowel preparation quality for colonoscopy in type 2 diabetes. World J Gastroenterol 2026; 32(46): 121313 [DOI: 10.3748/wjg.121313]
Corresponding Author of This Article
Eun Ran Kim, MD, PhD, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea. er.kim@samsung.com
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Park HJ, Oh YE, Chi SA, Kim M, Kim JE, Hong SN, Min BH, Kim YH, Chang DK, Kim TS, Kim ER. Impact of glucagon-like peptide-1 receptor agonists on bowel preparation quality for colonoscopy in type 2 diabetes. World J Gastroenterol 2026; 32(46): 121313 [DOI: 10.3748/wjg.121313]
Hyun Jung Park, Young Eun Oh, Minjee Kim, Ji Eun Kim, Sung Noh Hong, Byung-Hoon Min, Young-Ho Kim, Dong Kyung Chang, Tae-Se Kim, Eun Ran Kim, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, South Korea
Sang Ah Chi, Biomedical Statistics Center, Research Institute for Future Medicine, Samsung Medical Center, Seoul 06351, South Korea
Co-first authors: Hyun Jung Park and Young Eun Oh.
Co-corresponding authors: Tae-Se Kim and Eun Ran Kim.
Author contributions: Park HJ and Oh YE contributed equally to this work and are co-first authors; Park HJ and Oh YE drafted the manuscript; Park HJ, Oh YE, Kim TS, and Kim ER contributed to the conception and design of the study; Park HJ, Oh YE, Chi SA, Kim TS, and Kim ER contributed to the analysis and interpretation of the data; Kim M, Kim JE, Hong SN, Min BH, Kim YH, and Chang DK contributed to data acquisition and critically revised the manuscript for important intellectual content; Kim TS and Kim ER contributed equally as co-corresponding authors. All authors reviewed and approved the final manuscript and agree to be accountable for all aspects of the work.
AI contribution statement: No AI tools were used in a manner that requires disclosure under the AI tool usage policy.
Institutional review board statement: This study was approved by the Institutional Review Board of Samsung Medical Center, No. 2025-02-025.
Informed consent statement: The requirement for written informed consent was waived by the Institutional Review Board given the retrospective nature of the study.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Data sharing statement: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Corresponding author: Eun Ran Kim, MD, PhD, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul 06351, South Korea. er.kim@samsung.com
Received: April 7, 2026 Revised: June 11, 2026 Accepted: June 30, 2026 Published online: December 14, 2026 Processing time: 198 Days and 15.6 Hours
Abstract
BACKGROUND
Adequate bowel preparation is essential for high-quality colonoscopy because it directly affects mucosal visualization, adenoma detection, completion rate, and the need for repeat procedures. Patients with type 2 diabetes mellitus (T2DM) have a higher risk of inadequate bowel cleansing than the general population, partly because of delayed gastrointestinal motility and associated comorbidities. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly being prescribed for T2DM, but they can delay gastrointestinal transit, and potentially impair bowel preparation. However, clinical data on the effects of GLP-1RAs on bowel cleansing are limited.
AIM
To evaluate the association between GLP-1RA use and bowel preparation quality in patients with T2DM undergoing colonoscopy.
METHODS
We conducted a retrospective cohort study of patients with T2DM undergoing colonoscopy at a tertiary referral hospital in South Korea. After propensity score matching, we compared 133 patients receiving GLP-1RAs with 208 patients receiving dipeptidyl peptidase-4 inhibitors as an active comparator. The primary outcome was inadequate bowel preparation (IBP), defined as a total Boston Bowel Preparation Scale score < 6 or any segmental score < 2. Segment-specific bowel preparation quality, including right-colon cleansing, was also assessed.
RESULTS
IBP was more frequent in the GLP-1RA group than in the dipeptidyl peptidase-4 inhibitors group (25.6% vs 15.4%, P = 0.034). Right-colon IBP was also higher in the GLP-1RA group (24.1% vs 13.5%, P = 0.013) and mean right-colon Boston Bowel Preparation Scale score was consistently lower (1.9 ± 0.8 vs 2.1 ± 0.7, P = 0.031). In multivariable analysis, GLP-1RA use (adjusted odds ratio = 1.89; 95% confidence interval: 1.05-3.39, P = 0.034) and male sex (adjusted odds ratio = 2.46; 95% confidence interval: 1.24-4.89, P = 0.010) were identified as independent risk factors for IBP.
CONCLUSION
GLP-1RA use was associated with IBP in patients with T2DM, particularly in the right colon. Optimized bowel preparation protocols should be considered before colonoscopy in patients receiving GLP-1RAs.
Core Tip: Glucagon-like peptide-1 receptor agonists are increasingly used in patients with type 2 diabetes mellitus; however, their effect on bowel preparation quality before colonoscopy remains unclear. In this propensity score-matched cohort study, glucagon-like peptide-1 receptor agonist use was associated with a high risk of inadequate bowel preparation, particularly in the right colon. These findings highlight a practical issue in endoscopic practice and suggest that optimized bowel preparation strategies should be considered for patients receiving these agents.
Citation: Park HJ, Oh YE, Chi SA, Kim M, Kim JE, Hong SN, Min BH, Kim YH, Chang DK, Kim TS, Kim ER. Impact of glucagon-like peptide-1 receptor agonists on bowel preparation quality for colonoscopy in type 2 diabetes. World J Gastroenterol 2026; 32(46): 121313
Adequate bowel preparation is essential for high-quality colonoscopy, which is the gold standard for colorectal cancer (CRC) screening. Because diabetes is a well-established risk factor for CRC[1], ensuring optimal colonoscopy quality in patients with type 2 diabetes mellitus (T2DM) has significant clinical implications. Diabetes is also a recognized risk factor for inadequate bowel preparation (IBP)[2,3], potentially due to autonomic neuropathy, hyperglycemia and delayed gastrointestinal (GI) motility[4]. IBP occurs in approximately 15%-20% of screening colonoscopies[5] and is associated with reduced adenoma detection rates, prolonged procedure times, increased risk of adverse events, and the need for repeat procedures[6,7]. Given that screening colonoscopy significantly reduces the incidence and mortality of CRC[8], adequate bowel preparation is particularly crucial in patients with diabetes.
Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are widely used to treat T2DM and obesity. However, GLP-1RAs are also known to affect GI motility by delaying gastric emptying, slowing colonic transit, and suppressing postprandial motility[9-12], raising concerns about their clinical implications for endoscopic procedures. Recent studies investigating upper endoscopy have demonstrated an increased risk of retained gastric contents and aborted procedures in GLP-1RA users[13-17]. Consequently, earlier guidance often recommended temporary discontinuation of GLP-1RAs before elective procedures, while recent multi-society consensus statements have emphasized an individualized, shared decision-making approach[18-20]. Notably, current recommendations primarily focus on upper endoscopy and provide limited explicit guidance on the management of GLP-1RAs before colonoscopy, mainly because of the paucity of clinical evidence[21].
Previous studies have reported conflicting results regarding the effects of GLP-1RAs on bowel preparation quality[22-28]. Although some studies have found no statistically significant difference in IBP between patients treated with GLP-1RAs and controls[22,25], more recent studies have suggested an association between GLP-1RA use and suboptimal bowel preparation[23,24,26,27]. Furthermore, most of the available evidence has been derived from Western populations; thus, the effect of GLP-1RAs on bowel preparation in Asian patients with T2DM remains unclear. Therefore, we investigated this association using real-world clinical data from Asian patients with T2DM.
MATERIALS AND METHODS
Study design and patients
We conducted a single-center retrospective cohort study using propensity score matching among patients with T2DM who underwent colonoscopy while receiving treatment with GLP-1RAs or dipeptidyl peptidase-4 inhibitors (DPP-4is) at Samsung Medical Center between July 2016 and December 2024. Eligible participants were Korean patients aged 18 years or older with T2DM who were taking a GLP-1RA (e.g., dulaglutide, liraglutide, or lixisenatide) or DPP-4i (e.g., gemigliptin, linagliptin, or vildagliptin) at the time of colonoscopy. Patients with prescription records indicating that they had received GLP-1RA or DPP-4i therapy for at least 6 months prior to colonoscopy were included in the study. Both males and females were eligible and no participants were excluded based on sex. Patients treated with DPP-4is served as the active comparator group. DPP-4is are commonly prescribed glucose-lowering agents for T2DM and have an incretin-based therapeutic background similar to that of GLP-1RAs, while having minimal impact on gastric emptying and GI motility[29,30]. The active comparator group was used as the control group to reduce confounding related to diabetes treatment selection. In addition, current Korean and American clinical guidelines do not recommend the concomitant use of GLP-1RA and DPP-4i, thereby reducing the likelihood of exposure misclassification between case and control groups[31,32].
Exclusion criteria were as follows: Incomplete prescription records, history of previous GI surgery or major abdominal surgery, conditions affecting GI anatomy (such as GI malignancies, inflammatory bowel disease with structural complications, or congenital abnormalities), and colonoscopy conducted in an inpatient or emergency care setting. After exclusion, patients treated with GLP-1RAs were matched to those treated with DPP-4is in a 1:3 ratio using propensity score matching (Figure 1).
Figure 1 Flowchart of study population selection for glucagon-like peptide-1 receptor agonist users and propensity score-matched controls.
GLP-1RAs: Glucagon-like peptide-1 receptor agonists; DPP-4: Dipeptidyl peptidase-4; T2DM: Type 2 diabetes mellitus; GI: Gastrointestinal; BMI: Body mass index; HbA1c: Hemoglobin A1c; CKD: Chronic kidney disease.
All enrolled patients received approved bowel preparation regimens. Patients were instructed to consume a low-residue diet until 6: 00 PM on the day before colonoscopy and to consume only clear liquids thereafter until midnight. 2-L split-dose polyethylene glycol (PEG)-based purgatives were administered according to the scheduled procedure time: A split-dose regimen for the morning colonoscopy and a same-day regimen for the afternoon colonoscopy. In contrast, trisulfate-based purgatives were administered exclusively in a split-dose regimen[33]. All colonoscopies were performed by experienced, board-certified gastroenterologists. This study was approved by the Institutional Review Board of Samsung Medical Center, No. 2025-02-025. The requirement for written informed consent was waived because of the retrospective nature of the study. This study was conducted according to the guidelines of the Declaration of Helsinki.
Variables and definitions
Study participants who underwent colonoscopy while receiving treatment for T2DM with GLP-1RAs or DPP-4is were included. Patients were further selected according to the inclusion and exclusion criteria using the Clinical Data Warehouse tool of Samsung Medical Center, followed by a retrospective review of electronic medical records. Demographic and clinical data collected included age; sex; body mass index (BMI); diabetes duration; diabetes-related complications (e.g., diabetic retinopathy, diabetic neuropathy, and diabetic nephropathy); hemoglobin A1c (HbA1c) levels; and medication history within 3 months before colonoscopy, including metformin, insulin, and GI modulators (prokinetic agents, laxatives, tricyclic antidepressants, opioids, anticholinergic agents, and antidiarrheal agents).
Comorbidities at the time of colonoscopy were identified from electronic medical records and included hypertension, cardiovascular disease, cerebrovascular disease, and chronic kidney disease, which was defined as an estimated glomerular filtration rate < 60 mL/minute/1.73 m2, calculated using the equation proposed by the Chronic Kidney Disease Epidemiology Collaboration[34].
Bowel preparation was assessed using the Boston Bowel Preparation Scale (BBPS)[35]. Each colonic segment (right, transverse, and left colon) was scored on a scale ranging from 0 to 3, resulting in a total BBPS score ranging from 0 to 9. Aborted or repeated colonoscopies due to IBP with solid stool that could not be cleared by cleansing maneuvers were also recorded. BBPS scoring was performed by two endoscopists who independently reviewed colonoscopic images, and any discrepancies in scoring were resolved by reaching a consensus.
Outcomes
The primary outcome was IBP, defined as a total BBPS score < 6 or any segmental BBPS score < 2. Secondary outcomes included segmental bowel preparation quality, and aborted or repeated colonoscopies.
Statistical analysis
Patient characteristics were summarized as mean ± SD for continuous variables and as percentages for categorical variables. Before propensity score matching, continuous variables were compared using Student’s t-test or the Wilcoxon rank-sum test, while categorical variables were compared using the χ2 or Fisher’s exact test. To reduce selection bias between the GLP-1RA and DPP-4i groups, propensity score matching was performed. Propensity scores were estimated using a logistic regression model that included variables that showed significant differences between the two groups (age, BMI, diabetes duration, diabetes-related complications, chronic kidney disease, HbA1c, HbA1c ≥ 7%, insulin use and metformin use) as well as clinically relevant variables (sex). HbA1c level was analyzed both as a continuous and categorical variable using a cutoff of 7% to balance statistical precision with clinical interpretability.
A 1:3 propensity score-matched cohort was constructed using the nearest neighbor matching method without replacement[36]. The discriminatory power of the propensity score model was evaluated using c-statistics, and covariate balance before and after matching was visualized using a Love plot. After matching, logistic regression analyses using generalized estimating equation models were performed to identify risk factors associated with IBP. Variables with a P value < 0.1 in univariable analyses and clinically relevant covariates were included in the multivariable models. Variables with residual imbalance after propensity score matching, including age, BMI, HbA1c, and insulin use, were additionally adjusted for in the regression model. Overall, a doubly robust approach was applied by integrating the propensity score matching with multivariable outcome regression[37].
To evaluate the robustness of the primary findings, we performed two separate sensitivity analyses. First, the analysis was restricted to patients who had used PEG-based purgatives for colonoscopy. Second, the analysis was performed after excluding patients using GI modulator. Subgroup analyses were performed for IBP according to diabetes duration (< 10 years vs ≥ 10 years), HbA1c level (< 7% vs ≥ 7%), and BMI (< 25 kg/m2 vs ≥ 25 kg/m2). P values for interaction were assessed by adding interaction terms between GLP-1RA use and each subgroup variable in the multivariable analyses. All statistical methods were reviewed by a biostatistician at the Biomedical Statistics Center, Samsung Medical Center. All statistical analyses were performed using R version 4.2.2 (Vienna, Austria; http://www.R-project.org/).
RESULTS
Baseline characteristics
Table 1 summarizes the baseline characteristics of the study population before and after propensity score matching. Prior to matching, the GLP-1RA group (n = 153) was characterized by younger age, higher BMI and HbA1c levels, longer diabetes duration, more frequent use of insulin and metformin, and a higher prevalence of diabetes-related complications, whereas chronic kidney disease was less common, compared with the DPP-4i group (n = 436). After 1:3 propensity score matching (n = 341), no significant differences in the baseline clinical characteristics were observed between the GLP-1RA and DPP-4i groups. The absolute standardized mean differences for all covariates were substantially reduced after matching, indicating an adequate balance between the two groups. The propensity score model demonstrated good discriminative ability with a c-statistic of 0.83 [95% confidence interval (CI): 0.79-0.86]. The Love plot showed improved covariate balance after matching (Supplementary Figure 1).
Table 1 Characteristics of glucagon-like peptide-1 receptor agonist and dipeptidyl peptidase-4 inhibitor users before and after matching, mean ± SD/n (%).
In the matched cohort, a significantly higher incidence of IBP was observed among patients in the GLP-1RA group than among those in the DPP-4i group (25.6% vs 15.4%, P = 0.034). The proportion of aborted or repeated colonoscopies was higher in the GLP-1RA group than in the DPP-4i group, although the difference was not statistically significant (1.5% vs 0.5%, P = 0.569; Table 2).
Table 2 Procedural outcomes of glucagon-like peptide-1 receptor agonist users and dipeptidyl peptidase-4 inhibitor users before and after matching, mean ± SD/n (%).
Segmental assessment of bowel preparation demonstrated that the mean BBPS score was significantly lower in the right colon among patients treated with GLP-1RAs (1.9 ± 0.8 vs 2.1 ± 0.7, P = 0.031), whereas no significant differences were observed in the transverse or left colon (Table 2). Consistently, segment-specific analyses revealed a significantly higher incidence of IBP in the right colon in the GLP-1RA group than in the DPP-4i group (24.1% vs 13.5%, P = 0.013; Figure 2).
Figure 2 Incidence of inadequate bowel preparation by colonic segment in the matched cohort.
DPP-4i: Dipeptidyl peptidase-4 inhibitor; GLP-1RA: Glucagon-like peptide-1 receptor agonists.
Risk factors for IBP in the matched cohort
Univariable and multivariable logistic regression analyses were performed to identify risk factors for IBP in the matched cohort. In multivariable analysis, GLP-1RA treatment [adjusted odds ratio (OR) = 1.89; 95%CI: 1.05-3.39, P = 0.034] and male sex (adjusted OR = 2.46; 95%CI: 1.24-4.89, P = 0.010) were identified as the independent risk factors for IBP (Table 3).
Table 3 Multivariable analysis of risk factors for inadequate bowel preparation.
The distribution of GLP-1RA and DPP-4i subtypes among patients with IBP in the matched cohort is shown in Figure 3. In the GLP-1RA group, dulaglutide 1.5 mg constituted the largest proportion of cases (67.6%). In contrast, patients treated with DPP-4i demonstrated a relatively balanced distribution across agents, with gemigliptin, linagliptin, and vildagliptin accounting for 37.5%, 28.1%, and 34.4% of cases, respectively.
Figure 3 Distribution of glucagon-like peptide-1 receptor agonist and dipeptidyl peptidase-4 inhibitor subtypes among matched-cohort patients with inadequate bowel preparation.
A: Distribution of glucagon-like peptide-1 receptor agonist subtypes; B: Distribution of dipeptidyl peptidase-4 inhibitor subtypes. DPP-4: Dipeptidyl peptidase-4; GLP-1RAs: Glucagon-like peptide-1 receptor agonists.
The association between the GLP-1RA subtype and dose and the risk of IBP in the matched cohort is presented in Table 4. Compared with dulaglutide 0.75 mg, no GLP-1RA subtype or dose was associated with a statistically significant difference in the risk of IBP in either unadjusted or adjusted analyses. The full multivariable model, including clinical covariates, is provided in Supplementary Table 1.
Table 4 Association between glucagon-like peptide-1 receptor agonist subtype and the risk of inadequate bowel preparation.
In sensitivity analyses, the association between GLP-1RA use and IBP remained consistent. Among PEG-based purgative users, GLP-1RA use remained significantly associated with IBP (adjusted OR = 2.08; 95%CI: 1.17-3.72, P = 0.012). Similarly, among patients without GI modulator use, GLP-1RA use remained associated with a higher risk of IBP (adjusted OR = 2.19; 95%CI: 1.20-4.05, P = 0.011; Supplementary Table 2). Subgroup analyses showed no statistically significant interactions according to diabetes duration, HbA1c level, or BMI category (Supplementary Table 3).
DISCUSSION
In this propensity score-matched study, we found that GLP-1RA treatment in T2DM patients was significantly associated with an increased risk of IBP, with particularly lower BBPS scores in the right colon. To the best of our knowledge, this study is one of the largest retrospective analyses to investigate the impact of GLP-1RAs on bowel preparation quality in an Asian population with T2DM. These segment-specific findings of suboptimal bowel preparation raise concerns regarding the effectiveness of colonoscopy in the prevention and surveillance of CRC in patients with T2DM receiving GLP-1RA therapy.
In our matched cohort, the incidence of IBP was significantly higher among GLP-1RA users than among DPP-4i users (25.6% vs 15.4%, P = 0.034). Furthermore, GLP-1RA use was associated with a nearly twofold increased risk of IBP (OR = 1.89; 95%CI: 1.05-3.39, P = 0.034). The association between GLP-1RA use and IBP was also consistent in sensitivity analyses, thereby indicating the robustness of our findings.
Previous studies have reported mixed results regarding the effect of GLP-1RA on bowel preparation during colonoscopy. Sharma et al[22] reported comparable rates of satisfactory bowel preparation between 126 GLP-1RA users and 129 non-users with diabetes (92.06% vs 92.25%, P = 1.0). Similarly, Tong et al[25] found no statistically significant differences in the incidence of IBP among liraglutide, sitagliptin and control groups (17.5%, 20.5%, and 21.7%, respectively, P = 0.927).
In contrast, our findings are consistent with several recent studies suggesting a significant association between GLP-1RA use and poor bowel preparation[23,24,26,27]. By employing propensity score matching with a DPP-4i active comparator group, we aimed to reduce potential confounding associated with diabetes treatment and provided a more refined assessment of clinical differences than previous studies. Notably, our subgroup analysis revealed that the risk of IBP did not significantly differ across GLP-1RA subtypes or dosages, thereby indicating a possible class-related association of GLP-1RAs rather than an effect of specific agents and doses. This finding should, nevertheless, be interpreted with caution, given that the GLP-1RA cohort comprised predominantly dulaglutide users and the number of patients receiving other GLP-1RAs was limited. Furthermore, in our multivariable analysis, male sex was identified as an independent risk factor for IBP. This is consistent with previous reports suggesting that male patients may have lower compliance with bowel preparation instructions or have distinct physiological characteristics regarding colon transit[4]. However, our study was not primarily designed to evaluate sex-specific differences in bowel preparation quality, and sex-based analyses were limited to multivariable risk-factor assessment. Given the increasing use of GLP-1RAs for T2DM and obesity, both of which are associated with an elevated risk of colorectal neoplasia[1,38-40], our findings highlight an important clinical concern in this high-risk population. Considering these multifactorial patient-specific factors, tailored periprocedural strategies are essential for achieving high-quality colonoscopic surveillance among GLP-1RA users.
The association between GLP-1RA use and IBP is consistent with the known effects of GLP-1RAs on GI motility. GLP-1RAs are known to delay gastric emptying and slow intestinal transit via mechanisms mediated by both the central and peripheral cholinergic nervous systems[9-12]. In patients with T2DM, who are often predisposed to autonomic neuropathy or chronic hyperglycemia, these effects may be further amplified, which is consistent with the findings of Tong et al[25], who reported that adverse effects of GLP-1RA were particularly prominent in patients with diabetic peripheral neuropathy.
In our study, the effect of GLP-1RAs on bowel preparation was more prominent in the right colon. GLP-1RA use was significantly associated with the higher incidence of IBP (24.1% vs 13.5%, P = 0.013) and lower BBPS scores (1.9 ± 0.8 vs 2.1 ± 0.7, P = 0.031) in the right colon than in the control group. Although the absolute difference in right-colon BBPS scores was relatively small, the concomitant increase in right-colon IBP suggests that this finding may have potential clinical relevance; however it should be interpreted cautiously. The right colon is inherently difficult to cleanse because of prolonged fecal residence time, continuous influx of mucus and chyme from the small intestine, and anatomical blind spots such as haustral folds and the ileocecal valve. Delayed colonic transit associated with GLP-1RA use may further compound these underlying conditions. However, given that we did not directly assess colonic transit time or motility, the proposed mechanism for the right-colon-specific findings should be interpreted cautiously. Given that sessile serrated lesions (SSLs) are often flat and subtle in appearance, their detection depends on the quality of bowel preparation[41]. A recent study reported that GLP-1RA use was associated with increased odds of lower SSL detection, whereas the rate of adenoma detection remained unaffected[28]. As the detection of SSLs in the proximal colon is critical for the prevention of malignancy and interval cancers, GLP-1RA use may compromise optimal bowel cleansing in the right-side colon, potentially undermining the efficacy of screening.
Our study has certain limitations. First, this was a retrospective, single-center study conducted in a tertiary care setting and included only Korean outpatients, which may have introduced potential selection bias. Consequently, our findings may not be fully generalizable to primary care settings, hospitalized patients with complex comorbidities, other ethnic populations, or clinical settings in which dietary habits, lifestyle factors, and GLP-1RA prescribing patterns may differ. Second, although we used an active-comparator design, potential residual confounding cannot be entirely excluded, given that GLP-1RAs and DPP-4is are not fully comparable in terms of pharmacological potency, metabolic effects, weight-reduction effects, and GI adverse events.
Third, given the retrospective study design, details of certain factors that could potentially influence bowel preparation quality were not consistently available in the medical records. These included dietary or bowel preparation adherence, lifestyle-related factors, bowel motility-related comorbidities, prior colonoscopy experience, socioeconomic status, and detailed GLP-1RA exposure information, such as treatment duration and timing of the final dose. Consequently, residual confounding associated with these unmeasured factors cannot be completely excluded. Fourth, newer GLP-1RAs such as semaglutide or tirzepatide were not included, as they were not commercially available during the study period. Accordingly, the applicability of our findings to these newer agents may be limited.
Fifth, we did not assess adenoma detection rate, SSL detection rate, withdrawal time, or cecal intubation time. Future studies incorporating these quality indicators are needed to better clarify the clinical implications of our findings. In addition, although BBPS scoring was performed by two endoscopists who independently reviewed colonoscopic images, formal blinding to medication status was not performed and, consequently, we cannot completely exclude the possibility of observer bias in BBPS scoring.
Despite these limitations, our study provides valuable insights into the disproportionate impairment in right-sided bowel cleansing, including practice-relevant information beyond global bowel preparation scores. We employed an active comparator design using DPP-4i as the comparator and applied robust propensity score matching to enhance comparability between groups and mitigate confounding.
CONCLUSION
In conclusion, GLP-1RA treatment was associated with a significantly higher risk of IBP, which was particularly prominent in the right colon. Taking into consideration that adequate bowel preparation is essential for effective CRC screening, our findings indicate the need for increased clinical attention and adjusted bowel preparation strategies in patients receiving GLP-1RA therapy. Further prospective studies are needed to establish appropriate pre-procedural management strategies for this population.
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P-Reviewer: Losurdo G, Associate Professor, MD, PhD, Italy; Vignesh A, Assistant Professor, FASCRS, PhD, India S-Editor: Wu S L-Editor: A P-Editor: Zhang YL
