Risk Factor Analysis for 30-Day Mortality after Primary THA in a Single Institution

Abstract

The purpose of this study was to determine the prevalence of, and associated risk factors for, 30-day perioperative death following primary total hip arthroplasty (THA). Data of all the patients were compiled from the computerized total joint registry at a single institution. Between May 1993 and May 2006, 3,232 consecutive primary THA (2,453 elective and 779 nonelective) were performed. Eleven deaths occurred during the first month after surgery (0.34 %). Thirty-day mortality rate after elective THA was 0.08 % (two of 2,453 IC 95 %(0–0.4)). The 30-day mortality rate after nonelective THA was 1.15 % (nine of 779 IC 95 %(0.7–2.4). To analyze the factors that could have contributed with death, we conducted a 4-to-1 nested case–control study. Control cases were strictly matched by sex, age, surgeon, prosthesis fixation mode, and date of surgery. Conditional logistic regression was used to evaluate the association of risk factors with mortality. Elective surgery was associated with a lower risk of mortality with an odds ratio (OR) of 0.07 (95 % CI 0.008–0.6);p = 0.015. American Society of Anesthesiologists (ASA) score III–IV increased the mortality risk 13 times (OR 13.7; 95 % CI 1.6–114.8). Cardiovascular disease increased the risk for mortality eight times (OR 8.83 (95 % CI 1.78–43.6). Time delay before surgery showed a trend towards significance (p = 0.06). Aggressive vs. nonaggressive thromboembolism prophylaxis and the amount of blood transfusions required were not associated with a higher risk of death. Patients undergoing a THA due to fractures, patients with high ASA score, and those with cardiovascular disease were the highest risk factors for 30-day mortality after primary THA.