Background: Randomized controlled trials demonstrate the efficacy of arginine-enriched nutritional supplements (immunonutrition) in reducing complications after surgery. The effectiveness of preoperative immunonutrition has not been evaluated in a community setting.
Objective: This study aims to determine whether immunonutrition before elective colorectal surgery improves outcomes in the community at large.
Design: This is a prospective cohort study with a propensity score-matched comparative effectiveness evaluation.
Settings: This study was conducted in Washington State hospitals in the Surgical Care Outcomes Assessment Program from 2012 to 2015.
Patients: Adults undergoing elective colorectal surgery were selected.
Interventions: Surgeons used a preoperative checklist that recommended that patients take oral immunonutrition (237 mL, 3 times daily) for 5 days before elective colorectal resection.
Main outcome measures: Serious adverse events (infection, anastomotic leak, reoperation, and death) and prolonged length of stay were the primary outcomes measured.
Results: Three thousand three hundred seventy-five patients (mean age 59.9 ± 15.2 years, 56% female) underwent elective colorectal surgery. Patients receiving immunonutrition more commonly were in a higher ASA class (III-V, 44% vs 38%; p = 0.01) or required an ostomy (18% vs 14%; p = 0.02). The rate of serious adverse events was 6.8% vs 8.3% (p = 0.25) and the rate of prolonged length of stay was 13.8% vs 17.3% (p = 0.04) in those who did and did not receive immunonutrition. After propensity score matching, covariates were similar among 960 patients. Although differences in serious adverse events were nonsignificant (relative risk, 0.76; 95% CI, 0.49-1.16), prolonged length of stay (relative risk, 0.77; 95% CI, 0.58-1.01 p = 0.05) was lower in those receiving immunonutrition.
Limitations: Patient compliance with the intervention was not measured. Residual confounding, including surgeon-level heterogeneity, may influence estimates of the effect of immunonutrition.
Conclusions: Reductions in prolonged length of stay, likely related to fewer complications, support the use of immunonutrition in quality improvement initiatives related to elective colorectal surgery. This population-based study supports previous trials of immunonutrition, but shows a lower magnitude of benefit, perhaps related to compliance or a lower rate of adverse events, highlighting the value of community-based assessments of comparative effectiveness.