Effects of 24-hour urine-output trajectories on the risk of acute kidney injury in critically ill patients with cirrhosis: a retrospective cohort analysis

Figures & data

Table 1. Statistics for choosing the best number of classes.

Classes	Log likelihood	AIC	BIC	SABIC	Entropy	Class 1 (%)	Class 2 (%)	Class 3 (%)	Class 4 (%)	Class 5 (%)	Class 6 (%)
1	−14848.54	29711.07	29754.32	29732.07	1.000	100.00
2	−11616.88	23257.75	23331.88	23293.75	0.996	96.52	3.48
3	−9564.031	19162.06	19267.08	19213.06	0.867	5.11	81.57	13.32
4	−8830.367	17704.73	17840.63	17770.73	0.885	4.04	74.88	14.85	6.23
5	−7278.868	14621.74	14819.41	14717.73	0.885	3.14	67.15	18.78	7.95	2.98
6	−7654.784	15363.57	15530.38	15444.58	0.832	2.13	60.78	25.23	7.99	0.67	3.20

AIC: Akaike information criteria; BIC: Bayesian information criteria; SABIC: Sample-adjusted BIC.

Figure 1. The 24 h urine output trajectories in patients with cirrhotic.

Figure 2. The flowchart of patient selection. MIMIC: Medical Information Mort for Intensive Care; ICU: intensive care unit; AKI: acute kidney injury.

Table 2. Baseline characteristics of all included patients.

Variables	Overall	Class 1	Class 2	Class 3	Class 4	Class 5	p value
N (%)	3562 (100.00)	112 (3.14)	2392 (67.15)	669 (18.78)	283 (7.95)	106 (2.98)	< 0.001
Age, year	58.00 [51.00, 66.00]	58 [48.00, 65.00]	59.00 [51.75, 66.00]	56.00 [48.00, 64.00]	57.00 [50.00, 65.00]	55.00 [46.00, 64.00]	< 0.001
Gender (%)
Male	2297 (64.49)	76 (67.86)	1558 (65.13)	422 (63.08)	181 (63.96)	60 (56.60)	< 0.001
Female	1265 (35.51)	36 (32.14)	834 (34.87)	247 (36.92)	102 (36.04)	46 (43.40)	< 0.001
Ethnicity (%)
White Ethnicity	2447 (68.70)	85 (75.89)	1623 (67.85)	473 (70.71)	189 (66.78)	77 (72.64)	< 0.001
Black Ethnicity	278 (7.80)	8 (7.14)	191 (7.98)	48 (7.17)	21 (7.42)	10 (9.43)	< 0.001
Others	837 (23.50)	19 (16.97)	578 (24.17)	148 (22.12)	73 (25.80)	19 (17.93)	< 0.001
Admission type (%)
Emergency	2182 (61.26)	73 (65.18)	1424 (59.53)	447 (66.82)	170 (60.07)	68 (64.15)	< 0.001
Urgency	747 (20.97)	14 (12.50)	535 (22.37)	113 (16.89)	65 (22.97)	20 (18.87)	< 0.001
Surgery or observation	633 (17.77)	25 (22.32)	433 (18.10)	109 (16.29)	48 (16.96)	18 (16.98)	< 0.001
Antibiotic (%)	2829 (79.42)	82 (73.21)	1993 (83.32)	457 (68.31)	217 (76.68)	80 (75.47)	< 0.001
Ventilator (%)	2724 (76.47)	67 (59.82)	1964 (82.11)	425 (63.53)	199 (70.32)	69 (65.09)	< 0.001
Vasopressor (%)	450 (12.63)	4 (3.57)	364 (15.22)	42 (6.28)	36 (12.72)	4 (3.77)	< 0.001
SOFA	7.00 [5.00, 11.00]	6.00 [4.00, 8.00]	8.00 [6.00, 12.00]	6.00 [4.00, 8.00]	6.00 [4.00, 10.00]	5.00 [3.00, 7.00]	< 0.001
SAPSII	37.00 [28.00, 47.25]	33.00 [25.00, 38.00]	40.00 [31.00, 50.00]	31.00 [24.00, 39.00]	34.00 [26.00, 43.00]	28.00 [20.00, 37.00]	< 0.001
Comorbidity index	6.00 [5.00, 8.00]	6.00 [4.25, 8.00]	7.00 [5.00, 9.00]	6.00 [4.00, 8.00]	6.00 [5.00, 8.00]	6.00 [4.00, 8.25]	< 0.001
First-day fluid intake (%)
≤ 1000 ml	2031 (57.02)	80 (71.43)	1301 (54.39)	412 (61.59)	169 (59.72)	69 (65.10)	< 0.001
> 1000 ml but ≤ 3000 ml	815 (22.88)	18 (16.07)	563 (23.54)	148 (22.12)	65 (22.97)	21 (19.81)	< 0.001
> 3000 ml	716 (20.10)	14 (12.50)	528 (22.07)	109 (16.29)	49 (17.31)	16 (15.09)	< 0.001
VRWG ≥ 10%	97 (2.72)	0 (0.00)	80 (3.34)	7 (1.05)	5 (1.77)	5 (4.72)	< 0.001
Basic liver diseases (%)
Alcoholic	1790 (50.25)	60 (53.57)	1194 (49.92)	347 (51.87)	131 (46.29)	58 (54.72)	< 0.001
Nonalcoholic	1043 (29.28)	23 (20.54)	723 (30.23)	178 (26.61)	90 (31.81)	29 (27.36)	< 0.001
Biliary	109 (3.06)	4 (3.57)	61 (2.55)	27 (4.04)	13 (4.59)	4 (3.77)	< 0.001
Others	620 (17.41)	25 (22.32)	414 (17.30)	117 (17.48)	49 (17.31)	15 (14.15)	< 0.001
Laboratory
WBC (K/UL)	8.80 [5.80, 13.00]	7.28 [4.96, 11.94]	9.35 [6.25, 13.65]	7.60 [5.15, 11.30]	8.40 [5.60, 12.05]	7.78 [5.27, 10.94]	< 0.001
BUN (mg/dl)	24.00 [15.00, 40.50]	20.75 [11.13, 30.25]	26.00 [16.50, 44.00]	18.50 [11.00, 31.75]	22.50 [15.00, 40.50]	17.00 [12.50, 27.13]	< 0.001
Chloride (mEq/l)	103.00 [98.50, 107.50]	102.50 [99.00, 106.38]	103.50 [98.50, 107.50]	103.00 [98.25, 107.50]	102.50 [97.50, 107.50]	103.00 [98.50, 107.00]	< 0.001
Sodium (mEq/l)	137.50 [133.50, 140.50]	137.00 [135.00, 139.50]	137.00 [133.50, 140.50]	137.50 [134.00, 140.50]	137.00 [133.00, 140.50]	138 [133.38, 141.50]	< 0.001
Potassium (mEq/l)	4.15 [3.75, 4.70]	4.15 [3.86, 4.60]	4.20 [3.80, 4.75]	4.05 [3.70, 4.48]	4.15 [3.75, 4.70]	3.98 [3.74, 4.46]	< 0.001
Aniongap (mmol/l)	22.00 [19.00, 24.50]	22.25 [20.00, 25.50]	21.50 [18.50, 24.50]	23.00 [19.75, 25.00]	22.00 [19.00, 25.00]	22.50 [20.00, 26.00]	< 0.001
Bicarbonate (mmol/l)	14.50 [12.00, 17.50]	13.00 [11.00, 16.50]	15.00 [12.50, 17.50]	14.00 [12.00, 16.50]	14.50 [12.00, 17.50]	13.50 [12.00, 15.50]	< 0.001
Hemoglobin (g/dl)	9.40 [8.20, 10.85]	8.85 [7.56, 10.17]	9.40 [8.25, 10.75]	9.65 [8.28, 11.10]	9.30 [8.25, 11.20]	9.68 [8.20, 11.25]	< 0.001
Platelets (K/UL)	103.50 [68.50, 157.13]	93.75 [67.63, 139.88]	102.75 [68.00, 157.00]	104.50 [67.50, 158.75]	106.50 [69.50, 152.00]	115.25 [71.75, 175.75]	< 0.001
Glucose (mg/dl)	125.50 [104.50, 163.50]	126.25 [105.25, 154.63]	127.00 [105.00, 168.50]	119.50 [102.00, 155.50]	129.00 [102.00, 162.00]	122.75 [104.38, 142.13]	< 0.001
Basic creatinine (mg/dl)	1.10 [0.80, 1.70]	0.90 [0.70, 1.25]	1.10 [0.80, 1.80]	0.90 [0.70, 1.40]	1.00 [0.80, 1.50]	0.90 [0.70, 1.30]	< 0.001
Maximum creatinine (mg/dl)	1.20 [0.80, 2.00]	0.90 [0.70, 1.30]	1.30 [0.90, 2.20]	1.00 [0.70, 1.50]	1.10 [0.80, 1.80]	0.90 [0.90, 1.30]	< 0.001
Mean total urine output (mL/(kg h))	0.96 [0.47, 1.83]	2.40 [1.80, 3.45]	0.66 [0.31, 0.94]	2.31 [1.89, 2.93]	1.64 [1.21, 2.31]	2.10 [1.36, 2.86]	< 0.001
First six hour urine output (mL/(kg h))	0.93 [0.44, 1.95]	2.45 [1.84, 3.50]	0.58 [0.30, 0.94]	4.60 [3.65, 5.56]	2.49 [1.91, 3.13]	1.26 [0.78, 2.37]	< 0.001
Second six hour urine output (mL/(kg h))	0.92 [0.45, 1.74]	2.34 [1.77, 3.35]	0.59 [0.30, 0.94]	1.10 [0.87, 1.72]	1.34 [0.80, 2.01]	2.53 [1.71, 3.31]	< 0.001
Third six hour urine output (mL/(kg h))	0.92 [0.46, 1.96]	2.32 [1.79, 3.40]	0.60 [0.30, 0.94]	1.08 [0.85, 1.67]	1.32 [0.78, 1.98]	2.26 [1.62, 3.15]	< 0.001
Fourth six hour urine output (mL/(kg h))	0.93 [0.47, 1.71]	2.32 [1.78, 3.35]	0.62 [0.31, 0.95]	1.07 [0.77, 1.64]	1.29 [0.73, 1.95]	2.09 [1.49, 2.97]	< 0.001
AKI (n, %)	2467 (69.26%)	47 (41.96%)	1918 (80.18%)	283 (42.30%)	177 (62.54%)	42 (39.62%)	< 0.001

AKI: acute kidney injury; SAPSII: Simplify Acute Physiological Scores II; SOFA: Sequential Organ Failure Assessment; WBC: white blood cell; BUN: blood urea nitrogen; VRWG: volume-related weight gain.

Figure 3. Cumulative incidence curves based on cumulative incidence function.

Figure 4. Results of subdistribution hazard models. SHR: subdistribution hazard ratio; CI: confidence interval.

Table 3. Results of subgroup analyses.

Variables	Class 1	Class 2		Class 3		Class 4		Class 5		P for interaction
	SHR	SHR (95% CI)	p value	SHR (95% CI)	p value	SHR (95% CI)	p value	SHR (95% CI)	p value
Age (years)
< 65	1 (Ref)	2.39 (1.67–3.42)	< 0.001	1.70 (1.17–2.47)	< 0.001	1.65 (1.11–2.46)	< 0.001	0.77 (0.44–1.32)	0.350	0.005
≥ 65	1 (Ref)	2.99 (1.55–5.79)	< 0.001	2.32 (1.17–4.57)	0.015	2.31 (1.13–4.73)	0.021	2.11 (0.92–4.83)	0.076
Gender
Male	1 (Ref)	3.77 (2.02–7.03)	< 0.001	2.63 (1.38–4.98)	0.003	2.91 (1.50–5.62)	< 0.001	1.58 (0.72–3.49)	0.250	< 0.001
Female	1 (Ref)	2.12 (1.49–3.03)	< 0.001	1.63 (1.07–2.27)	0.019	1.48 (0.99–2.22)	0.052	0.85 (0.48–1.50)	0.590
Ethnicity
White Ethnicity	1 (Ref)	2.56 (1.82–3.61)	< 0.001	1.80 (1.25–2.59)	< 0.001	1.77 (1.20–2.62)	0.003	0.94 (0.56–1.57)	0.820	0.156
Black Ethnicity	1 (Ref)	2.61 (0.48–14.20)	0.270	1.98 (0.35–11.12)	0.440	2.41 (0.39–14.56)	0.340	0.89 (0.09–8.56)	0.920
Others	1 (Ref)	2.28 (0.98–5.30)	0.054	1.79 (0.76–4.22)	1.180	1.69 (0.69–4.09)	0.240	1.40 (0.51–3.88)	0.510
Antibiotic
No	1 (Ref)	2.70 (1.45–5.00)	< 0.001	1.512 (0.78–2.91)	0.220	1.66 (0.82–3.39)	0.160	0.65 (0.23–1.77)	0.400	< 0.001
Yes	1 (Ref)	2.47 (1.71–3.56)	< 0.001	1.89 (1.29–2.77)	< 0.001	1.81 (1.21–2.71)	0.003	1.20 (0.72–1.99)	0.470
Mechanical ventilation
No	1 (Ref)	2.65 (1.58–4.43)	< 0.001	1.13 (0.65–1.96)	0.660	1.08 (0.57–2.05)	0.790	0.93 (0.41–2.10)	0.880	< 0.001
Yes	1 (Ref)	2.52 (1.73–3.66)	< 0.001	1.99 (1.35–2.95)	< 0.001	2.12 (1.42–3.17)	0.003	1.12 (0.66–1.89)	0.470
Vasopressor
No	1 (Ref)	2.55 (1.83–3.56)	< 0.001	1.78 (1.26–2.52)	< 0.001	1.67 (1.15–2.41)	0.006	0.96 (0.59–1.54)	0.870	0.010
Yes	1 (Ref)	2.58 (1.00–6.67)	0.049	2.64 (0.99–7.02)	0.051	2.88 (1.03–8.01)	0.042	2.19 (1.14–8.93)	0.027
SOFA
< 3	1 (Ref)	2.18 (0.86–5.50)	0.098	0.79 (0.27–2.25)	0.660	0.63 (0.19–2.02)	0.450	0.23 (0.05–1.03)	0.056	< 0.001
≥ 3	1 (Ref)	2.57 (1.84–3.60)	< 0.001	1.90 (1.34–2.70)	< 0.001	1.94 (1.34–2.81)	< 0.001	1.15 (0.71–1.87)	0.560
SAPSII
< 35	1 (Ref)	3.29 (2.06–5.24)	< 0.001	2.10 (1.29–3.41)	0.002	1.75 (1.04–2.94)	0.033	1.05 (0.55–2.02)	0.870	0.045
≥ 35	1 (Ref)	1.95 (1.27–3.00)	0.002	1.54 (0.98–2.42)	0.058	1.69 (1.05–2.71)	0.030	1.00 (0.53–1.88)	0.990
Comorbidity index
< 5	1 (Ref)	2.58 (1.34–4.97)	0.004	1.74 (0.88–3.45)	0.110	1.27 (0.60–2.67)	0.520	0.53 (0.18–1.52)	0.240	< 0.001
≥ 5	1 (Ref)	2.74 (1.77–3.64)	< 0.001	1.87 (1.28–2.72)	< 0.001	1.98 (1.33–2.95)	< 0.001	1.24 (0.75–2.04)	0.400

SAPSII: Simplify Acute Physiological Scores II; SOFA: Sequential Organ Failure Assessment; SHR: sub-distribution hazard ratio; CI: confidence interval.

Data availability statement

Data of this study were obtained from the MIMIC-IV database, which was a publicly available dataset, which were exhibited in Materials and Methods.