Putative risk factor | Univariate analysis | Multivariable analysis | ||
---|---|---|---|---|
 | Hazard ratio (95% confidence interval) | P value | Hazard ratio (95% confidence interval) | P value |
Baseline factors | Â | Â | Â | Â |
   Age (10-year increase) | 0.82 (0.58 to 1.15) | 0.25 | - | - |
   Acute Physiology and Chronic Health Evaluation II score (10-point increase) | 0.97 (0.49 to 1.93) | 0.93 | - | - |
   Surgical patient | 1.76 (0.50 to 6.26) | 0.38 | - | - |
   Baseline renal disease classification (with reference to acute renal failure) |  |  |  |  |
Acute on chronic | 0.92 (0.18 to 4.56) | 0.91 | Â | Â |
Chronic renal failurea | - | - | Â | Â |
Chronic hemodialysis | 3.59 (0.71 to 18.15) | 0.12 | Â | Â |
Time-dependent factors | Â | Â | Â | Â |
   Exposure to continuous hemodialysisb | 2.17 (0.55 to 8.51) | 0.27 | - | - |
   Exposure to intermittent hemodialysisb | 1.25 (0.32 to 4.85) | 0.75 | - | - |
   Exposure to therapeutic-dose unfractionated heparinb | 2.87 (0.59 to 13.97) | 0.19 | - | - |
   Exposure to prophylactic-dose unfractionated heparinb | 1.10 (0.14 to 8.80) | 0.93 | - | - |
   Exposure to acetylsalicylic acidb | 3.62 (0.93 to 14.11) | 0.06 | 6.30 (1.35 to 29.35) | 0.02 |
   Detectable trough anti-activated factor X level (≥ 0.01 IU/ml) | 0.76 (0.15 to 3.81) | 0.74 | - | - |
   International Normalized Ratio (0.5-unit increase) | 1.44 (0.95 to 2.17) | 0.09 | 1.68 (1.07 to 2.66) | 0.03 |
   Partial thromboplastin time (10-unit increase) | 1.13 (0.99 to 1.29) | 0.06 | - | - |
   Platelet count (50-unit decrease) | 1.19 (0.94 to 1.51) | 0.16 | - | - |