Table 4.

Intention-to-treat Cox proportional hazards model of associations between key covariates and time to all-cause mortality or initiation of dialysis

CovariateUnivariable Analysis, Derivation CohortParsimonious Multivariable Model, Derivation CohortShort Multivariable Model, Derivation Cohort
HR (95% CI)P Value HR (95% CI)P Value HR (95% CI)P Value
Demographics
 Age (per 10 yr)1.01 (0.96–1.06)0.891.05 (0.99–1.11)0.08
 Male sex1.31 (1.12–1.54)0.001
 Black (versus other races)0.60 (0.49–0.74)<0.0010.68 (0.55–0.84)<0.001
Hospital location
 Surgical service (versus medical service)0.68 (0.58–0.79)<0.0010.48 (0.41–0.57)<0.0010.45 (0.39–0.53)<0.001
 ICU (versus other hospital location)4.82 (4.16–5.57)<0.0011.91 (1.61–2.27)<0.0013.12 (2.67–3.65)<0.001
Comorbidities (present at admission)
 HIV0.47 (0.20–1.08)0.22
 Congestive heart failure1.07 (0.91–1.25)0.370.86 (0.73–1.02)0.08
 Diabetes0.93 (0.77–1.11)0.23
 Liver disease2.61 (2.22–3.07)<0.0011.92 (1.63–2.27)<0.0012.12 (1.81–2.50)<0.001
 Malignancy1.35 (1.06–1.72)0.01
 Metastatic solid tumor1.78 (1.40–2.26)<0.0011.67 (1.31–2.13)<0.001
 Myocardial infarction1.13 (0.91–1.42)0.33
 Peptic ulcer disease1.61 (1.08–2.39)0.02
 Peripheral vascular disease1.11 (0.89–1.37)0.61
 Pulmonary disease0.82 (0.59–1.13)0.25
Laboratory values
 Baseline creatinine (per 0.1 mg/dl)1.11 (1.07–1.14)<0.001
 Bicarbonate (per mEq/L)0.87 (0.85–0.88)<0.0010.96 (0.94–0.97)<0.001
 BUN (per 10 mg/dl)1.23 (1.21–1.26)<0.0011.09 (1.06–1.12)<0.001
 Change in creatinine from day prior (per 0.1 mg/dl)1.08 (1.07–1.10)<0.0011.04 (1.03–1.04)<0.0011.04 (1.03–1.05)<0.001
 Creatinine (per mg/dl)1.66 (1.58–1.76)<0.0011.26 (1.17–1.35)<0.0011.42 (1.35–1.50)<0.001
 Potassium (per mEq/L)1.92 (1.81–2.03)<0.0011.24 (1.16–1.33)<0.001
Medications
 Number of sedatives (per drug)1.73 (1.64–1.82)<0.0011.08 (1.01–1.16)0.02
 Prior aminoglycoside exposure1.03 (0.86–1.22)0.83
 Number of antibiotics (per drug)1.42 (1.37–1.47)<0.0011.09 (1.05–1.14)<0.001
 Number of pressors (per drug)1.98 (1.88–2.09)<0.0011.32 (1.24–1.42)<0.0011.52 (1.44–1.61)<0.001
 Paralytic exposure4.39 (3.60–5.34)<0.0011.61 (1.30–1.99)<0.001
 Thiazide diuretic1.35 (1.13–1.61)0.002
Other orders
 Ventilated3.62 (3.17–4.14)<0.0011.34 (1.15–1.56)<0.001
  • n=35,462 patient-days, 3951 patients, and 1031 outcome events. Data censored at 14 days from the onset of AKI or August 31, 2010, whichever came first. Data exclude patient-days after placement of a do not resuscitate order. HR, hazard ratio; CI, confidence interval; ICU, intensive care unit.