The Impact of the Implementation of the Enhanced Recovery After Surgery (ERASA®) Program in an Entire Health System: A Natural Experiment in Alberta, Canada

The Enhanced Recovery After Surgery (ERAS) program has been shown to reduce length of stay (LOS) in colorectal surgical patients in randomized trials. The impact outside of trial settings, or in subgroups of patients excluded from trials such as individuals with diabetes, is uncertain. We conducted this study to evaluate the impact of ERAS implementation in Alberta, Canada. This is a retrospective cohort study and interrupted time series analysis using linked administrative data to examine LOS and postoperative outcomes in the 12 months pre- and post-implementation of ERAS in 2013 for all adults undergoing elective colorectal surgery. Of 2714 patients (mean age 60.4 years, 55% men) with similar demographics and comorbidity profiles in the pre/post-ERAS time periods, LOS was significantly shorter post-ERAS (8.5 vs. 9.5 days, p = 0.01; - 0.84 days [95% CI - 0.04 to - 1.64 days] after adjustment for age, sex, Charlson comorbidity score, procedure type, surgical approach, and hospital). However, interrupted time series demonstrated no significant level change (p = 0.30) or change in slope (p = 0.63) with ERAS implementation, consistent with continuation of an underlying secular trend of reductions in LOS over time. There were no significant differences (in multivariate analysis or ITS) in risk of 30-day death/readmission (14.3% post vs. 13.5% pre-ERAS, aOR 1.12, 95% CI 0.89-1.40), 30-day death/ED visit (27.2% post vs. 30.0% pre, aOR 0.93, 95% CI 0.78-1.10), or 30-day death/readmission/ED visit (27.8% post vs. 30.6% pre, aOR 0.93, 95% CI 0.78-1.10). The 428 patients with diabetes had longer LOS but exhibited no significant difference post- versus pre-ERAS (10.7 vs. 11.6 days, p = 0.53; p = 0.56 for level change and p = 0.66 for slope change on ITS). Although there was a secular trend toward decreasing LOS over time in Alberta, ERAS implementation was not associated with statistically significant changes in LOS or postoperative outcomes for all colorectal surgery patients or for those with diabetes. Our study highlights the importance of evaluating system changes (for both uptake and outcomes) rather than assuming trial benefits will translate directly into practice. Interventions to improve LOS and postoperative outcomes for patients with diabetes undergoing colorectal surgery are still needed even in the ERAS era.