. Author manuscript; available in PMC: 2024 Jan 1.

Published in final edited form as: Am J Kidney Dis. 2022 Jul 19;81(1):36–47. doi: 10.1053/j.ajkd.2022.06.004

Table 1.

Patient characteristics in the study cohorts

Variables	UKY Cohort (Derivation) n = 7354	UTSW Cohort (Validation) n = 2233
Age, years, median [IQR25th-75^th]	63.02 [51.71–73.55]	63.98 [53.84–73.68]
Gender, male, n (%)	4111 (55.90)	1277 (57.19)
Race, n (%)
- White	6734 (91.57)	1392 (62.34)
- Black	501 (6.81)	504 (22.57)
- Other	119 (1.62)	337 (15.09)
BMI, kg/m², median [IQR25th-75^th]	29.07 [24.62–34.95]	28.65 [24.44–34.25]
Comorbidity
Charlson Score, median [IQR25th-75^th]	3.00 [1.00–5.00]	4.00 [2.00–6.00]
Elixhauser Score, median [IQR25th-75^th]	6.00 [4.00–8.00]	6.00 [4.00–8.00]
Diabetes, n (%)	3062 (41.64)	927 (41.51)
Hypertension, n (%)	5623 (76.46)	1657 (74.21)
Baseline eGFR, mL/min/1.73m², median [IQR25th-75^th] ^#	78.52 [54.53–99.21]	70.31 [47.29–95.13]
CKD, n (%) ^#	604 (8.21)	439 (19.66)
Critical Illness characteristics
SOFA Score^*, median [IQR25th-75^th]	6.00 [4.00–8.00]	6.00 [4.00–8.00]
APACHE II Score^*, median [IQR25th-75^th]	19.00 [16.00–23.00]	17.00 [14.00–22.00]
Pressor/Inotrope^*, n (%)	1568 (21.32)	327 (15.20)
Hospital LOS, days, median [IQR25th-75^th]	11.49 [6.44–21.29]	10.34 [6.43–18.27]
ICU LOS^*, hours, median [IQR25th-75^th]	76.55 [61.17–83.6]	76.02 [54.43–81.45]
ECMO^*, n (%)	101 (1.37)	12 (0.54)
Mechanical ventilation^*, n (%)	3822 (51.97)	914 (40.93)
MV days^*, median [IQR25th-75^th]	3.00 [1.27–3.43]	3.00 [1.00–3.36]
Sepsis on ICU admission, n (%)	1942 (26.41)	456 (20.42)
Urine output^*, mL/h, median [IQR25th-75^th]	68.90 [39.67–110.42]	60.01 [39.42–90.13]
Urine flow^*, mL/kg/h, median [IQR25th-75^th]	0.81 [0.45–1.37]	0.72 [0.47–1.08]
Fluid Overload^*, %, median [IQR25th-75^th]	4.36 [0.01–10.76]	0.70 [−1.69 to 3.68]
Laboratory Data
Bicarbonate^*, mmol/L, median [IQR25th-75^th]	21.50 [18.50–24.50]	22.50 [19.50–25.00]
BUN^*, mg/dL, median [IQR25th-75^th]	39.00 [27.00–58.00]	31.00 [21.00–48.00]
Hematocrit^*, %, median [IQR25th-75^th]	30.45 [26.40–35.50]	30.20 [26.49–34.80]
Hemoglobin^*, g/dL, median [IQR25th-75^th]	10.10 [8.75–11.85]	10.05 [8.80–11.60]
AKI Characteristics
Baseline sCr, mg/dL, median [IQR25th-75^th] #	0.96 [0.75–1.25]	1.04 [0.78–1.40]
ICU admission sCr, mg/dL, median [IQR25th-75^th]	1.60 [1.15–2.31]	1.45 [1.00–2.15]
Peak sCr D0–D3, mg/dL, median [IQR25th-75^th]	1.94 [1.47–2.84]	1.86 [1.40–2.70]
Last sCr D0–D3, mg/dL, median [IQR25th-75^th]	1.47 [1.08–2.15]	1.46 [1.05–2.09]
Maximum KDIGO D0–D3, n (%)
- Stage 1	3564 (48.46)	1291 (57.81)
- Stage 2	1786 (24.29)	457 (20.47)
- Stage 3	2004 (27.25)	485 (21.72)
Last KDIGO D0–D3, n (%)
- No AKI	2641 (35.91)	872 (39.05)
- Stage 1	2089 (28.41)	720 (32.24)
- Stage 2	1085 (14.75)	265 (11.87)
- Stage 3	1539 (20.93)	376 (16.84)
Inpatient Dialysis Characteristics
CRRT^* only, n (%)	576 (7.83)	158 (7.08)
HD^* only, n (%)	243 (3.30)	26 (1.16)
CRRT and HD both^*, n (%)	5 (0.07)	3 (0.13)
Total days of CRRT^*, median [IQR25th-75^th]	3.00 [2.00–4.00]	3.00 [2.00–3.00]
Total days of HD^*, median [IQR25th-75^th]	2.46 [1.59–3.00]	2.00 [1.00–3.00]

Measured or calculated with data within the first 3 days of ICU admission.

Reported only for patients with measured baseline sCr.

Abbreviations: AKI (acute kidney injury), APACHE (acute physiologic assessment and chronic health evaluation), BMI (body mass index), BUN (blood urea nitrogen), CKD (chronic kidney disease), CRRT (continuous renal replacement therapy), D0–D3 (from day 0 to day 3 of ICU admission), ECMO (extracorporeal membrane oxygenation), HD (hemodialysis), IABP (intra-aortic balloon pump), ICU (intensive care unit), IQR (interquartile range), KDIGO (Kidney Disease: Improving Global Outcomes), LOS (length of stay), MV (mechanical ventilation), SCr (serum creatinine), SOFA (sequential organ failure assessment), UKY (University of Kentucky), UTSW (University of Texas Southwestern).