Introduction: Current literature tends not to adjust for biases in patient selection attributable to comorbidities that could provide alternate explanations for length of stay differences in laparoscopic versus open colectomy. We hypothesized that utilizing the National Surgical Quality Improvement Program (NSQIP) dataset and acuity adjustment methods would demonstrate an independent improvement in length of stay for laparoscopic colectomy.
Methods: We used CPT coding to select all colectomies in NSQIP public use files from 2005-2009. Outlier status for surgical length of stay (SLOS) was defined as >75th percentile. Logistic regression analysis was used to predict this outlier status and linear regression to directly predict SLOS. Acuity adjustment was performed by using the most prevalent variables from multiple NSQIP annual reports. This work was done under the approval of our institutional review board and the data use agreement of the American College of Surgeons. Data were analyzed by using SPSS(®).
Results: A total of 45,645 colectomies were reviewed, of which 12,455 (27.3%) were laparoscopic. The 75th percentile for SLOS was 11 days. This implied that 9,249 (27.9%) of the open colectomies were outliers, whereas only 1,152 (9.2%) of laparoscopic colectomies were outliers (p < 0.001). When optimizing a simple linear regression to predict SLOS, using common acuity adjustors (i.e., age, functional status, wound category, etc.), the variable marking open procedures consistently had a coefficient of 1.8, implying that open procedures increased SLOS by 1.8 days (p < 0.001). Utilizing logistic regression to predict outlier status, open colectomies were associated with an odds ratio of 3.79 for outlier status (p < 0.001), thus implying an independent effect on SLOS.
Conclusions: These results indicate that laparoscopic colectomy independently decreases SLOS compared with open colectomy. This study is unique in using statistical methods to control for selection bias of patients who might be more "surgically fit."