Nonlinear association between estimated plasma volume status and acute kidney injury in acute pancreatitis patients

Table 2 Baseline characteristics of included patients grouped by tertile of estimated plasma volume status using Duarte and Kaplan-Hakim formula, mean ± SD/n (%)

Characteristics	D-ePVS formula				KH-ePVS formula
	T1 (n = 505) (< 4.231 dL/g)	T2 (n = 504) (4.231-5.358 dL/g)	T3 (n = 505) (≥ 5.358 dL/g)	P value	T1 (n = 505) (< -7.425)	T2 (n = 504) (-7.425-2.669)	T3 (n = 505) (≥ 2.669)	P value
Male	401 (79.7)	239 (47.6)	166 (33)	< 0.001	363 (72.2)	211 (42)	232 (46.1)	< 0.001
Age (years), median (IQR)	46.0 (36.0, 57.0)	55.0 (44.0, 65.0)	59.0 (48.0, 69.0)	< 0.001	45.0 (35.0, 56.0)	54.0 (46.0, 66.0)	60.0 (50.0, 70.0)	< 0.001
Death	9 (1.8)	2 (0.4)	12 (2.4)	0.031	493 (98)	500 (99.6)	492 (97.8)	0.04
ICU	75 (14.9)	51 (10.2)	116 (23.1)	< 0.001	75 (14.9)	51 (10.2)	116 (23.1)	< 0.001
LOS (day), median (IQR)	12.0 (10.0, 17.0)	13.0 (10.0, 18.0)	14.0 (10.0, 22.0)	< 0.001	12.0 (10.0, 17.0)	12.0 (10.0, 18.0)	14.0 (10.0, 23.0)	< 0.001
Hypertension	119 (23.7)	132 (26.3)	141 (28)	0.281	118 (23.5)	149 (29.7)	125 (24.9)	0.062
DM	85 (16.9)	62 (12.4)	77 (15.3)	0.121	95 (18.9)	60 (12)	69 (13.7)	0.006
CHD	477 (94.8)	473 (94.2)	455 (90.5)	0.012	26 (5.2)	32 (6.4)	45 (8.9)	0.053
SBP (mmHg), median (IQR)	130.0 (120.0, 144.0)	130.0 (118.0, 144.0)	125.0 (112.0, 140.0)	< 0.001	130.0 (120.0, 146.0)	130.0 (118.0, 142.0)	125.0 (111.0, 140.0)	< 0.001
DBP (mmHg), median (IQR)	85.0 (78.0, 94.0)	80.0 (72.0, 90.0)	78.0 (69.0, 85.5)	< 0.001	86.0 (78.0, 95.0)	80.0 (72.0, 90.0)	77.0 (69.0, 85.0)	< 0.001
HR (bpm), median (IQR)	82.0 (75.0, 100.0)	78.0 (72.0, 90.0)	80.0 (72.0, 92.0)	< 0.001	82.0 (75.0, 99.0)	78.0 (72.0, 89.8)	80.0 (72.0, 94.0)	< 0.001
RR (bpm), median (IQR)	20.0 (19.0, 20.0)	20.0 (19.0, 20.0)	20.0 (18.0, 20.0)	0.002	20.0 (19.0, 20.0)	20.0 (19.0, 20.0)	20.0 (18.0, 20.0)	< 0.001
SpO2 (%), median (IQR)	99.0 (97.0, 100.0)	99.0 (97.0, 100.0)	99.0 (98.0, 100.0)	0.464	99.0 (97.0, 100.0)	99.0 (97.0, 100.0)	99.0 (97.0, 100.0)	0.318
Mechanical ventilation (%)	52 (10.3)	37 (7.4)	67 (13.3)	0.008	46 (9.1)	31 (6.2)	79 (15.7)	< 0.001
Transfusion (%)	41 (8.2)	30 (6)	92 (18.3)	< 0.001	35 (7)	27 (5.4)	101 (20.1)	< 0.001
CRRT (%)	38 (7.6)	12 (2.4)	37 (7.4)	< 0.001	37 (7.4)	12 (2.4)	38 (7.6)	< 0.001
WBC (× 109/L), median (IQR)	11.9 (8.4, 15.2)	9.6 (6.5, 12.8)	8.3 (5.6, 11.9)	< 0.001	11.8 (8.5, 14.8)	9.3 (6.5, 12.9)	8.3 (5.6, 12.3)	< 0.001
HGB (g/L), median (IQR)	152.0 (144.0, 162.0)	129.0 (125.0, 134.0)	108.0 (98.0, 114.0)	< 0.001	151.0 (141.0, 161.0)	128.0 (120.0, 136.0)	109.0 (98.0, 119.0)	< 0.001
HCT (%), median (IQR)	44.5 (42.5, 47.2)	38.6 (37.2, 40.0)	32.8 (30.0, 34.6)	< 0.001	44.3 (42.0, 47.2)	38.0 (36.4, 40.1)	33.0 (30.0, 35.6)	< 0.001
PCT (ng/mL), median (IQR)	0.2 (0.1, 0.9)	0.1 (0.0, 0.6)	0.3 (0.1, 1.2)	< 0.001	0.2 (0.1, 0.7)	0.1 (0.0, 0.5)	0.3 (0.1, 1.4)	< 0.001
CRP (mg/L), median (IQR)	37.3 (7.3, 130.7)	27.4 (4.1, 123.2)	53.3 (7.6, 139.0)	0.007	34.7 (7.1, 138.1)	32.8 (5.3, 134.7)	45.9 (7.2, 133.4)	0.194
AST (U/L), median (IQR)	38.0 (23.2, 121.5)	44.2 (24.0, 152.5)	41.0 (22.0, 143.5)	0.435	38.0 (23.0, 134.0)	42.0 (22.7, 143.8)	42.0 (22.0, 137.4)	0.919
ALB (g/dL), median (IQR)	41.1 (37.4, 44.3)	38.9 (35.3, 42.5)	35.0 (29.6, 39.2)	< 0.001	41.4 (37.9, 44.4)	38.4 (34.9, 41.9)	35.2 (29.6, 39.4)	< 0.001
FPG (mmol/L), median (IQR)	7.5 (6.0, 11.5)	6.5 (5.3, 8.7)	6.1 (5.0, 7.8)	< 0.001	7.8 (6.0, 11.9)	6.4 (5.2, 8.4)	6.2 (5.0, 7.8)	< 0.001
TG (mmol/L), median (IQR)	2.4 (1.2, 7.7)	1.4 (0.9, 2.7)	1.3 (0.9, 2.2)	< 0.001	2.5 (1.2, 7.4)	1.4 (1.0, 2.7)	1.2 (0.9, 2.2)	< 0.001
Na+ (mmol/L), median (IQR)	138.8 (135.5, 141.1)	139.8 (137.2, 142.2)	139.9 (137.3, 141.9)	< 0.001	139.1 (135.8, 141.2)	139.9 (137.3, 142.4)	139.6 (136.9, 141.8)	< 0.001
Ca2+ (mmol/L), median (IQR)	2.3 (2.1, 2.4)	2.2 (2.1, 2.4)	2.1 (2.0, 2.3)	< 0.001	2.2 (2.1, 2.4)	2.2 (2.1, 2.4)	2.1 (2.0, 2.3)	< 0.001
AMY (U/L), median (IQR)	236.0 (85.0, 875.5)	193.0 (68.3, 650.8)	117.0 (59.0, 433.0)	< 0.001	251.0 (78.2, 921.0)	182.7 (68.3, 574.0)	128.0 (60.0, 466.0)	< 0.001
CREA (μmol/L), median (IQR)	80.0 (69.0, 92.0)	71.1 (59.0, 84.1)	71.0 (58.0, 88.0)	< 0.001	79.0 (67.0, 91.0)	70.0 (58.7, 81.8)	75.0 (60.0, 90.0)	< 0.001
AKI	91 (18.1)	55 (11)	105 (20.9)	< 0.001	81 (16.1)	62 (12.4)	108 (21.5)	< 0.001
Etiology				< 0.001				< 0.001
Biliary	276 (54.9)	367 (73.1)	374 (74.4)		272 (54.1)	372 (74.1)	373 (74.2)
Hyperlipidemic	186 (37)	97 (19.3)	70 (13.9)		189 (37.6)	99 (19.7)	65 (12.9)
Alcoholic	28 (5.6)	13 (2.6)	9 (1.8)		29 (5.8)	12 (2.4)	9 (1.8)
Others	13 (2.6)	25 (5)	50 (9.9)		13 (2.6)	19 (3.8)	56 (11.1)
SOFA (score)	2.5 ± 2.4	2.5 ± 2.2	3.1 ± 2.8	< 0.001	2.4 ± 2.2	2.5 ± 2.2	3.2 ± 2.9	< 0.001
BISAP (score)	1.3 ± 1.1	1.2 ± 1.2	1.4 ± 1.2	0.004	1.3 ± 1.1	1.2 ± 1.1	1.5 ± 1.2	< 0.001
Severity of AP				0.006				< 0.001
Mild and moderate	434 (86.3)	467 (93.0)	439 (87.3)		442 (87.9)	472 (94.0)	426 (84.7)
Severe	69 (13.7)	35 (7.0)	64 (12.7)		61 (12.1)	30 (6.0)	77 (15.3)

IQR: Interquartile range; D-ePVS: Duarte formula-based estimated plasma volume status; KH-ePVS: Kaplan-Hakim formula-based estimated plasma volume status; ICU: Intensive care unit; LOS: Length of hospital stay; DM: Diabetes mellitus; CHD: Coronary heart disease; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; HR: Heart rate; RR: Respiratory rate; SpO₂: Pulse oxygen saturation; CRRT: Continuous renal replacement treatment; WBC: White blood cell count; HGB: Hemoglobin; HCT: Hematocrit; PCT: Procalcitonin; CRP: C-reactive protein; AST: Aspartate aminotransferase; ALB: Albumin; FPG: Fasting plasma glucose; TG: Triglyceride; Na⁺: Sodium; Ca²⁺: Calcium; AMY: Amylase; CREA: Creatinine; AKI: Acute kidney injury; SOFA: Sequential organ failure assessment score; BISAP: Bedside index of severity in acute pancreatitis score; AP: Acute pancreatitis.