The more the better?: the impact of surgeon and hospital volume on in-hospital mortality following colorectal resection

Abstract

Objective: To determine the in-hospital mortality rates for patients undergoing colorectal resection for malignant or benign conditions, and to identify risk factors for in-hospital death, particularly the relationships with surgeon and hospital volume.

Background: Although there is strong evidence that complex cancer operations are best performed at specialized high-volume centers and by high-volume surgeons, the relationship between surgeon and hospital volume and perioperative outcomes is less well defined for more common procedures such as colorectal resections, particularly for benign diseases.

Methods: We obtained data from the Canadian Institute for Health Information Discharge Abstract Database on all adult patients who underwent colorectal resection between April 1, 2005 and March 31, 2006. We performed a logistic regression to identify variables associated with a higher likelihood of in-hospital death.

Results: Twenty-one thousand seventy-four patients underwent colorectal resection, with the majority being elective (59.4%). Malignancy represented the most common indication for resection (56.8%), followed by diverticular disease (16.2%) and inflammatory bowel disease (7.1%). The overall in-hospital mortality rate among patients undergoing colorectal resection was 5.3%. Increased age (adjusted Odds Ratio [OR]: 1.97 per 10 years, P < 0.001), urgent operation (OR: 2.63, P < 0.001), indication for resection (P < 0.001), nature of the surgery (P < 0.001), and several comorbidities were all independently associated with an increased risk of death. Surgeons with higher volumes of colorectal resections achieved significantly lower mortality rates (OR: 0.92 per 20 cases/y, P = 0.003), corresponding to an adjusted mortality rate of 5.6% for surgeons in the bottom decile (1 case per year) compared with 4.5% for surgeons in the top decile (greater than 43 cases per year). Hospital volume was not associated with mortality (OR: 1.00 per 10 cases, P = 0.504).

Conclusions: This large, population-based study suggests that surgeons who perform high volumes of colorectal resections achieve lower in-hospital mortality rates than surgeons with low volumes, whereas the hospital volume does not influence mortality.