Table 2.
Results of multivariable Cox regression analysis to evaluate the independent risk factors for 90-day postoperative mortality in Medicare patients undergoing TKA
| Comorbid conditions | Risk of 90-day postoperative mortality with condition | Risk of 90-day postoperative mortality without condition | Crude relative risk (95% CI) | Adjusted hazard ratio (95% CI) | Wald’s chi-square | p |
|---|---|---|---|---|---|---|
| Congestive heart failure* | 1.93% | 0.49% | 3.94 (3.27–4.75) | 2.15 (1.71–2.69) | 43.64 | <0.0001 |
| Metastatic cancer* | 3.43% | 0.61% | 5.64 (3.60–8.86) | 4.40 (2.67–7.26) | 33.61 | <0.0001 |
| Renal disease* | 2.20% | 0.58% | 3.80 (2.87–5.03) | 2.23 (1.68–2.96) | 30.82 | <0.0001 |
| Hypercholesterolemia† | 0.45% | 0.69% | 0.65 (0.52–0.82) | 0.64 (0.50–0.80) | 14.14 | 0.0002 |
| Peripheral vascular disease* | 1.30% | 0.54% | 2.42 (1.98–2.95) | 1.49 (1.20–1.87) | 12.63 | 0.0004 |
| Cerebrovascular disease* | 1.31% | 0.55% | 2.39 (1.95–2.94) | 1.49 (1.19–1.87) | 12.02 | 0.0005 |
| Lymphoma* | 1.76% | 0.62% | 2.84 (1.57–5.14) | 2.20 (1.22–4.0) | 6.78 | 0.0092 |
| Cardiac arrhythmia* | 1.12% | 0.51% | 2.19 (1.82–2.62) | 1.26 (1.04–1.54) | 5.39 | 0.0203 |
| Dementia* | 2.44% | 0.61% | 3.98 (2.43–6.51) | 1.84 (1.10–3.07) | 5.36 | 0.0206 |
| Pulmonary circulation disorders* | 2.11% | 0.61% | 3.47 (2.27–5.29) | 1.72 (1.07–2.76) | 5.07 | 0.0243 |
| Chronic liver disease* | 1.20% | 0.61% | 1.96 (1.29–2.96) | 1.50 (1.01–2.21) | 4.14 | 0.0420 |
| Chronic pulmonary disease | 0.95% | 0.56% | 1.70 (1.41–2.07) | 1.18 (0.97–1.43) | 2.75 | 0.0973 |
| Diabetes | 0.79% | 0.58% | 1.37 (1.14–1.66) | 1.17 (0.96–1.42) | 2.35 | 0.1249 |
| Ischemic heart disease | 0.97% | 0.50% | 1.95 (1.64–2.32) | 1.16 (0.96–1.39) | 2.29 | 0.1304 |
| Depression | 0.87% | 0.61% | 1.43 (1.06–1.91) | 1.25 (0.91–1.72) | 1.94 | 0.1639 |
| Anemia | 1.03% | 0.59% | 1.76 (1.38–2.24) | 1.17 (0.90–1.53) | 1.32 | 0.2503 |
| Peptic ulcer disease | 0.75% | 0.63% | 1.21 (0.54–2.69) | 0.65 (0.29–1.47) | 1.07 | 0.3002 |
| Alcohol abuse | 1.66% | 0.62% | 2.67 (1.11–6.39) | 1.43 (0.56–3.65) | 0.56 | 0.4549 |
| Urinary tract infection | 0.80% | 0.59% | 1.36 (1.11–1.67) | 1.07 (0.87–1.32) | 0.40 | 0.5266 |
| Obesity | 0.56% | 0.63% | 0.88 (0.61–1.28) | 0.89 (0.60–1.31) | 0.36 | 0.5464 |
| Valvular disease | 1.00% | 0.57% | 1.73 (1.40–2.15) | 0.93 (0.74–1.18) | 0.33 | 0.5654 |
| Rheumatologic disease | 0.67% | 0.62% | 1.08 (0.78–1.49) | 0.92 (0.66–1.28) | 0.27 | 0.6065 |
| Hypertension | 0.66% | 0.55% | 1.21 (0.99–1.47) | 0.95 (0.78–1.16) | 0.22 | 0.6374 |
| Drug abuse | 0.62% | 0.63% | 0.99 (0.14–7.01) | 0.64 (0.09–4.70) | 0.20 | 0.6584 |
| Coagulopathy | 1.05% | 0.61% | 1.73 (1.23–2.43) | 1.07 (0.76–1.52) | 0.17 | 0.6843 |
| Hypothyroidism | 0.63% | 0.63% | 1.00 (0.80–1.26) | 0.97 (0.77–1.23) | 0.06 | 0.8073 |
| Malignancy | 0.82% | 0.58% | 1.40 (1.15–1.71) | 0.98 (0.79–1.22) | 0.02 | 0.8773 |
| Psychoses | 0.93% | 0.62% | 1.51 (1.02–2.23) | 0.98 (0.61–1.59) | 0.01 | 0.9411 |
| Hemiplegia/paraplegia | 1.36% | 0.62% | 2.18 (0.82–5.79) | 1.01 (0.37–2.78) | 0.00 | 0.9838 |
* Condition that is statistically significantly associated with an increased adjusted risk of 90-day post operative mortality in Medicare patients undergoing THA; conditions are listed in descending order of the degree of association with 90-day postoperative mortality based on the p value associated with the hazard ratio; †condition that is associated with a decreased risk of 90-day postoperative mortality; PJI = prosthetic joint infection; CI = confidence interval.