Aspirin and non-aspirin NSAIDs increase risk of colonic diverticular bleeding: a systematic review and meta-analysis

Lower gastrointestinal bleeding is a frequent cause of hospitalization, particularly in the elderly, and its incidence appears to be on the rise. Colonic diverticular bleeding is the most common form of lower gastrointestinal bleeding and is responsible for 30-40 % of bleeding episodes. Risk factors associated with diverticular bleeding include obesity, hypertension, anticoagulants, diabetes mellitus, and ischemic heart disease. Recent studies have suggested a relationship between usage of non-steroidal anti-inflammatory drugs (NSAIDs) and colonic diverticular bleeding; however, most studies were small with wide confidence intervals. We identified studies by searching the PubMed and Scopus databases (from inception through 31 December 2012) and by searching bibliographies of relevant articles. Summary relative risks (RRs) with 95 % confidence intervals (CIs) were calculated with fixed-effects and random-effects models. A total of six studies (five case-control studies and one cohort study) met inclusion criteria for analysis. Non-aspirin NSAIDs (NANSAIDs) and aspirin were associated with an increased risk of colonic diverticular bleeding (summary RR = 2.48, 95 % CI 1.86-3.31), with moderate heterogeneity among these studies (P heterogeneity = 0.11, I (2) = 44.4 %). Stratification to evaluate the heterogeneity found that both NANSAIDs (summary RR = 2.24, 95 % CI 1.63-3.09; 5 studies) and aspirin (summary RR = 1.73; 95 % CI 1.31-2.30; 3 studies) were associated with the risk of diverticular bleeding. Aspirin/NANSAIDs use was strongly and consistently associated with an increased risk of colonic diverticular bleeding. Further studies are needed to stratify individuals at risk of diverticular bleeding associated with the use of these agents.