Table 2.

Intention-to-treat Cox proportional hazards model of associations between key covariates and time to initiation of dialytic therapy

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)0.96 (0.90–1.02)0.20
 Male sex1.52 (1.20–1.92)0.001
 Black (versus other races)0.53 (0.39–0.74)<0.0010.63 (0.46–0.86)0.004
Hospital location
 Surgical service (versusmedical service)1.05 (0.83–1.33)0.660.70 (0.55–0.90)0.01
 ICU (versus other hospital location)5.68 (4.55–7.09)<0.0011.93 (1.52–2.45)<0.0012.98 (2.35–3.78)<0.001
Comorbidities (present at admission)
 HIV0.15 (0.03–0.76)0.02
 Congestive heart failure1.19 (0.95–1.50)0.13
 Diabetes1.06 (0.82–1.37)0.641.27 (1.00–1.62)0.05
 Liver disease3.70 (2.95–4.63)<0.0012.45 (1.94–3.09)<0.0012.75 (2.18–3.47)<0.001
 Malignancy0.72 (0.46–1.11)0.14
 Metastatic solid tumor0.86 (0.53–1.42)0.56
 Myocardial infarction1.13 (0.82–1.55)0.46
 Peptic ulcer disease2.15 (1.32–3.50)0.002
 Peripheral vascular disease1.10 (0.81–1.49)0.54
 Pulmonary disease0.73 (0.45–1.20)0.22
Laboratory values
 Baseline creatinine (per 0.1 mg/dl)1.19 (1.14–1.24)<0.001
 Bicarbonate (per mEq/L)0.86 (0.84–0.88)<0.0010.95 (0.93–0.98)<0.001
 BUN (per 10 mg/dl)1.27 (1.24–1.30)<0.0011.07 (1.03–1.10)<0.001
 Change in creatinine from day prior (per 0.1 mg/dl)1.09 (1.08–1.11)<0.0011.02 (1.02–1.03)<0.0011.02 (1.01–1.03)<0.001
 Creatinine (per mg/dl)1.86 (1.75–1.99)<0.0011.53 (1.41–1.67)<0.0011.64 (1.54–1.76)<0.001
 Potassium (per mEq/L)2.08 (1.94–2.23)<0.0011.27 (1.16–1.40)<0.0011.35 (1.23–1.48)<0.001
Medications
 Number of sedatives (per drug)1.81 (1.68–1.94)<0.0011.14 (1.04–1.26)0.01
 Prior aminoglycoside exposure1.20 (0.95–1.53)0.13
 Number of antibiotics (per drug)1.42 (1.35–1.49)<0.0011.12 (1.06–1.19)<0.001
 Number of pressors (per drug)2.12 (1.98–2.26)<0.0011.28 (1.18–1.40)<0.0011.44 (1.33–1.55)<0.001
 Paralytic exposure4.55 (3.50–5.92)<0.0011.40 (1.03–1.90)0.03
 Thiazide diuretic2.25 (1.83–2.76)<0.0011.63 (1.33–2.00)<0.001
Other orders
 Ventilated3.71 (3.07–4.49)<0.0011.22 (0.99–1.51)0.06
  • n=35,462 patient-days, 3951 patients, and 471 outcome events. Data were censored at discharge, death, or 14 days from the onset of AKI, whichever came first. Data excludes patient-days after placement of a do not resuscitate order. HR, hazard ratio; CI, confidence interval; ICU, intensive care unit.