Complications and Month of Surgery: Does Scheduling Make a Difference?

Objective: This study evaluated if there were differences in perioperative morbidity associated with elective surgery based on the month in which surgery was performed. An electronic medical record review identified factors that influenced adverse events related to surgical procedures with the goals of improving health care quality and enhancing outcomes. This institutional review board–approved, retrospective cohort study examined persons ages 18 and older undergoing surgery in the main operating suites of a large 2-hospital community-based system from 2015 to 2016. The hypothesis was that that surgical complication rates would be higher at the end of the calendar year (November/December) than other months. Materials and Methods: Surgical data—including perioperative complications, comorbidities, descriptive statistics, and trainee involvement—were collected. A sample size of 10,000 charts per year was used, with equal numbers of charts randomly selected for each month. The charts were manually audited for the review. Results: After random selections, 19,872 subjects' charts were included. Baseline characteristics did not differ among months. Complications were associated with 17.7% of surgeries; reoperations (10%) and readmissions (5.9%) were most common. Probability of complications was 1.4 times greater for June ( odds ratio [ OR ] = 1.38; 95% confidence interval [CI]: 1.22–1.55; p < 0.001) and November ( OR = 1.41; 95% CI: 1.25–1.59; p < 0.001). Trainee involvement was not associated with increased complications ( OR = 1.05; 95% CI: 0.97–1.13; p = 0.240). Medicare/Medicaid patients had significantly higher complications ( OR = 1.97; 95% CI: 1.83–2.13; p ≤ 0.001). Conclusions: Patients who undergo surgery in June and November, and those who have Medicare/Medicaid, had significantly more complications. This study was registered with the National Clinical Trials Registry: NCT02958293.