Postoperative complication rates after hepatic resection in Maryland hospitals

Hypothesis: High-volume centers provide superior quality care and therefore have a lower incidence of postoperative complications. Design: Observational statewide administrative database. Setting: State of Maryland, nonfederal acute-care hospital (n = 52), performing liver resection (n = 35). Patients: All patients discharged after undergoing hepatic resection from 1994 to 1998 (N = 569). Main Outcome Measures: Two sequential analyses using multiple logistic regression of in-hospital mortality were performed to determine the relative importance of preoperative case-mix and postoperative complications. Results: The overall in-hospital mortality rate was 4.8% and was significantly lower in high-volume hospitals (2.8%) than in low-volume hospitals (10.2%) (P<.001). After adjusting for case-mix in the multivariate analysis, low hospital volume was associated with a 3-fold increase in mortality (odds ratio, 3.1; 95% confidence interval [CI], 1.2-7.6; P=.02). Having surgery at a low-volume hospital was associated with increased rates of several postoperative complications: reintubation (relative risk [RR], 2.5; 95% CI, 1.8-3.4), pulmonary failure (RR, 2.3; 95% CI, 1.6-3.5), pneumonia (RR, 0.35; 95% CI, 1.0-5.6), acute renal failure (RR, 2.0; 95% CI, 1.1-3.7), acute myocardial infarction (RR, 2.6; 95% CI, 1.2-5.9), and aspiration (RR, 1.4; 95% CI, 0.9-2.0). When considering all other factors using statistical methods, hospital volume was no longer associated with mortality. Conclusions: Patients who undergo hepatic resection at low-volume hospitals are at a higher risk of postoperative complications and death than those who have the same operation at high-volume hospitals. The empirical difference between outcomes at high- and low-volume hospitals seems to be due to a variation in postoperative complications.