Case volume as a predictor of inpatient mortality after esophagectomy

Hypothesis: Volume criteria are poor predictors of inpatient mortality after esophagectomy. Because many factors influence mortality for complex procedures, this study was designed to quantify such factors and analyze the volume-outcome relationship for esophagectomy. Design: Retrospective review of the Nationwide Inpatient Sample database for esophagectomies. We performed multivariate analysis to identify patient and institution risk factors for death and, by using all reported volume thresholds, calculated the probability of choosing a provider with a low mortality. Patients and Setting: Patients undergoing esophagectomy between January 1, 1988, and December 31, 2000, included in the Nationwide Inpatient Sample database. Main Outcome Measure: Inpatient mortality Results: We identified 8075 cases of esophagectomy; 3243 had complete data sets. The national average mortality rate was 11.4%. Independent risk factors for mortality included comorbidity, age (> 65 years), female sex, race, and surgeon volume. Choosing a surgeon or hospital on the basis of a particular volume threshold had a modest influence on the probability of that provider having a low mortality. A low-volume hospital (defined by the Leapfrog Group criterion as < 13 cases per year) had a probability of 6.1% of having a mortality of less than 10%, whereas a high-volume hospital had a probability of 68%. Conclusions: Patient factors have a greater influence on inpatient mortality than case volume does. Although there is generally an inverse relationship between case volume and mortality, there is wide scatter between individual surgeons and hospitals, with a complex volume-outcome relationship. Using volume criteria alone to choose a provider may in some instances increase the risk of mortality.