Risk of Postoperative Venous Thromboembolism After Benign Colorectal Surgery: Systematic Review and Meta-analysis.

Background: Venous thromboembolism is a well-established preventable complication after colectomy. Specific guidance on venous thromboembolism prevention after colectomy for benign disease is limited.

Objective: This meta-analysis aimed to quantify the venous thromboembolism risk after benign colorectal resection and determine its variability.

Data Sources: Following Preferred Reporting Items for Systematic Review and Meta-Analysis and Meta-analysis of Observational Studies in Epidemiology Guidelines (PROSPERO: CRD42021265438), Embase, MEDLINE, and 4 other registered medical literature databases were searched from the database inception to June 21, 2021.

Study Selection: Inclusion criteria: randomized controlled trials and large population-based database cohort studies reporting 30-day and 90-day venous thromboembolism rates after benign colorectal resection in patients aged ≥18 years. Exclusion criteria: patients undergoing colorectal cancer or completely endoscopic surgery.

Main Outcome Measures: Thirty- and 90-day venous thromboembolism incidence rates per 1000 person-years after benign colorectal surgery.

Results: Seventeen studies were eligible for meta-analysis reporting on 250,170 patients. Pooled 30-day and 90-day venous thromboembolism incidence rates after benign colorectal resection were 284 (95% CI, 224-360) and 84 (95% CI, 33-218) per 1000 person-years. Stratified by admission type, 30-day venous thromboembolism incidence rates per 1000 person-years were 532 (95% CI, 447-664) for emergency resections and 213 (95% CI, 100-453) for elective colorectal resections. Thirty-day venous thromboembolism incidence rates per 1000 person-years after colectomy were 485 (95% CI, 411-573) for patients with ulcerative colitis, 228 (95% CI, 181-288) for patients with Crohn's disease, and 208 (95% CI, 152-288) for patients with diverticulitis.

Limitations: High degree of heterogeneity was observed within most meta-analyses attributable to large cohorts minimizing within-study variance.

Conclusions: Venous thromboembolism rates remain high up to 90 days after colectomy and vary by indication for surgery. Emergency resections compared to elective benign resections have higher rates of postoperative venous thromboembolism. Further studies reporting venous thromboembolism rates by type of benign disease need to stratify rates by admission type to more accurately define venous thromboembolism risk after colectomy.

Registration No: CRD42021265438.