Risk Factors for Prolonged Postoperative Ileus in Colorectal Surgery: A Systematic Review and Meta-analysis

Background Prolonged postoperative ileus (PPOI) represents a frequent complication following colorectal surgery, affecting approximately 10-15% of these patients. The objective of this study was to evaluate the perioperative risk factors for PPOI development in colorectal surgery. Methods The present systematic review and meta-analysis was conducted in accordance with the PRISMA Statement. PubMed, EMBASE, SciELO, and LILACS databases were searched, without language or time restrictions, from inception until December 2018. The keywords used were: Ileus, colon, colorectal, sigmoid, rectal, postoperative, postoperatory, surgery, risk, factors. The Newcastle-Ottawa scale and the Jadad scale were used for bias assessment, while the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used for quality assessment of evidence on outcome levels. Results Of the 64 studies included, 42 were evaluated in the meta-analysis, comprising 29,736 patients (51.84% males; mean age 62 years), of whom 2844 (9.56%) developed PPOI. Significant risk factors for PPOI development were: male sex (OR 1.43; 95% CI 1.25-1.63), age (MD 3.17; 95% CI 1.63-4.71), cardiac comorbidities (OR 1.54; 95% CI 1.19-2.00), previous abdominal surgery (OR 1.44; 95% CI 1.19, 1.75), laparotomy (OR 2.47; 95% CI 1.77-3.44), and ostomy creation (OR 1.44; 95% CI 1.04-1.98). Included studies evidenced a moderate heterogeneity. The quality of evidence was regarded as very low-moderate according to the GRADE approach. Conclusions Multiple factors, including demographic characteristics, past medical history, and surgical approach, may increase the risk of developing PPOI in colorectal surgery patients. The awareness of these will allow a more accurate assessment of PPOI risk in order to take measures to decrease its impact on this population.