Benchmarking Surgical Quality: Cholecystectomy at a Safety-Net Hospital

BACKGROUND: Rates of conversion from laparoscopic to open cholecystectomy in the U.S. have been reported to be 5 to 10%. This study aims to benchmark conversion rate and identify preoperative factors that are predictive of conversion at a large, safety-net hospital. OBJECTIVE: To identify preoperative factors predictive of conversion from laparoscopic to open cholecystectomy for improved risk-adjustment of conversion as a quality indicator METHODS: The data for all patients who underwent laparoscopic and converted cholecystectomies from 2007 to 2015 were retrospectively abstracted from the electronic medical records of a public, teaching hospital. Variability in conversion rate was assessed over the time period captured in the study cohort. Univariate and multivariate logistic regression were used to identify the factors that are significantly associated with conversion. RESULTS: We identified 9,008 patients: 84.0% were female, 77.8% were Hispanic, and 75.2% were uninsured, with a median age of 37 years old. American Society of Anesthesiologists (ASA) 3 and 4 constituted 10.5% of patients. The majority (81.8%) of cases were performed between 7 a.m. and 3 p.m. There were 451 converted cholecystectomies across all case types - a conversion rate of 5.0%. On multivariable analysis, predictors of conversion were male gender (odds ratio (OR)=2.68; 95% confidence interval (CI): 2.09-3.43), increased age (OR=1.02; 95% CI: 1.02-1.03), diabetes mellitus (OR=1.42; 95% CI: 1.04-1.95), increased BMI (OR=1.018; 95% CI: 1.001-1.03), increased WBC count (OR=1.034; 95% CI: 1.01-1.06), and increased alkaline phosphatase (OR=1.002; 95% CI: 1.001-1.003). CONCLUSION: This is the largest single institution study to present a risk predictor for cholecystectomy conversion. The proposed risk score includes gender, diabetes mellitus, age, case type, BMI and two lab values - white blood cell count and alkaline phosphatase. These variables are readily available to providers pre-operatively, enabling application of this risk score to patient education and surgical planning.