To study the impact of different adherence levels to the enhanced recovery after surgery (ERAS) protocol and the effect of various ERAS elements on outcomes following major surgery. Single-center prospective cohort study before and after reinforcement of an ERAS protocol. Comparisons were made both between and across periods using multivariate logistic regression. All clinical data (114 variables) were prospectively recorded. Ersta Hospital, Stockholm, Sweden. Nine hundred fifty-three consecutive patients with colorectal cancer: 464 patients treated in 2002 to 2004 and 489 in 2005 to 2007. The association between improved adherence to the ERAS protocol and the incidence of postoperative symptoms, complications, and length of stay following major colorectal cancer surgery was analyzed. Following an overall increase in preoperative and perioperative adherence to the ERAS protocol from 43.3% in 2002 to 2004 to 70.6% in 2005 to 2007, both postoperative complications (odds ratio, 0.73; 95% confidence interval, 0.55-0.98) and symptoms (odds ratio, 0.53; 95% confidence interval, 0.40-0.70) declined significantly. Restriction of intravenous fluid and use of a preoperative carbohydrate drink were major independent predictors. Across periods, the proportion of adverse postoperative outcomes (30-day morbidity, symptoms, and readmissions) was significantly reduced with increasing adherence to the ERAS protocol (>70%, >80%, and >90%) compared with low ERAS adherence (<50%). Improved adherence to the standardized multimodal ERAS protocol is significantly associated with improved clinical outcomes following major colorectal cancer surgery, indicating a dose-response relationship.
