Table 4.

Multivariable models for incident/progressive CKD (dependent variable) in the 6 CKD/AKI groups (independent variable)

Variable	Model 1 aHR (95% CI)	p	Model 2 aHR (95% CI)	P
no-CKD
no-AKI	Reference		Reference
AKI 1	2.11 (1.33–3.35)	0.001	2.13 (1.34–3.37)	0.001
AKI ≥2	2.72 (1.74–4.25)	<0.001	2.79 (1.79–4.34)	<0.001
CKD
no-AKI	0.92 (0.54–1.58)	0.769	0.94 (0.55–1.61)	0.835
AKI 1	0.95 (0.54–1.67)	0.863	0.96 (0.54–1.68)	0.878
AKI ≥2	2.21 (1.35–3.64)	0.002	2.33 (1.43–3.80)	<0.001
Age, per 1 yr	1.01 (1.00–1.02)	0.093	1.01 (1.00–1.02)	0.112
African American	1.28 (0.97–1.71)	0.083	1.28 (0.96–1.70)	0.087
Male gender	0.98 (0.74–1.30)	0.880	0.98 (0.74–1.29)	0.867
Diabetes	0.98 (0.71–1.36)	0.924	0.98 (0.71–1.36)	0.921
Systolic heart failure	0.85 (0.40–1.82)	0.678	—
Anemia	1.87 (1.10–3.18)	0.021	1.88 (1.11–3.19)	0.019
Nonrenal SOFA ≥4	1.57 (1.14–2.15)	0.005	1.48 (1.11–1.98)	0.008
Mechanical ventilation	0.83 (0.60–1.15)	0.259	—
RBC transfusion	0.87 (0.35–2.13)	0.760	—
LOS, per 1 d	1.11 (0.81–1.51)	0.505	—
Exposure to statins	0.93 (0.69–1.27)	0.671	—

APACHE II score was not included in the models due to collinearity with the SOFA score; aHR, adjusted hazard ratio; AKI, acute kidney injury; APACHE II, Acute Physiology and Chronic Health Evaluation II; CI, confidence interval; CKD, chronic kidney disease; LOS, length of stay in the hospital; RBC, red blood cells; SOFA, Sequential Organ Failure Assessment.

Data are aHRs and 95% CIs for incident/progressive CKD by Cox proportional hazard regression. Model 1 included all tested variables, while model 2 includes variables of deemed particular clinical relevance (age, race, gender, diabetes), together with additional variables that were retained through backward selection (cut-off for retention: P < 0.10).