Does higher surgical volume predict better patient outcomes?

OBJECTIVE: To measure the relationship between procedural volume and quality by examining the association between hospital procedural volume and mortality in coronary artery bypass graft (CABG) and percutaneous transluminal coronary angioplasty (PTCA). METHODS: A retrospective quantitative analysis was conducted of Kentucky hospital discharge database for patients who underwent CABG and PTCA from 2000 through 2005. Hospitals were classified into three categories based on annual number of procedures--low (12-249), medium (250-499), and high-volume (> or = 500) CABG and PTCA facilities. This study employed a multiple logistic regression model to compare the odds for fatal outcome for patients treated in high, medium, and low-volume facilities, while controlling for patient age, gender, admission urgency, hospital length-of-stay, case severity, and pre-existing clinical conditions. RESULTS: From 2000 through 2005, 24 facilities performed 47,972 CABGs, while 30 facilities performed 75,869 PTCAs across the state of Kentucky. In non-emergent CABG and PTCA patients between the ages of 18 to 65 years, there was no statistically significant difference in the odds for fatal outcomes between low-, medium-, and high-volume hospitals. However, older (> or = 65 years old) emergent CABG and PTCA patients were more likely to die at high-volume and low-volume hospitals than medium-volume hospitals (odds ratio for CABG surgery--1.260 [1.004-1.580], 1.753 [1.266-2.4261, and odds ratio for PTCA--1.106 [1.207-2.163], 1.616 [1.207-2.163]). CONCLUSIONS: This study indicates that in hospital procedural volume Kentucky, is an imprecise predictor of quality as measured by CABG and PTCA outcomes, and should not be used by purchasers and policy makers as the only index of hospital quality.