Anti-hypertensive medications and risk of colorectal cancer: a systematic review and meta-analysis.

Abstract

Antihypertensive medications may impact colorectal cancer risk. We conducted a systematic review and meta-analysis of associations, with colorectal cancer risk, of five classes of antihypertensive medications: angiotensin-converting enzyme inhibitors (ACEIs), angiotensin II receptor blockers (ARBs), beta-blockers (BBs), calcium channel blockers (CCBs), and diuretics. A systematic search was conducted in MEDLINE, Embase, Web of Science, and the Cochrane library to identify relevant studies evaluating associations of ACEIs, ARBs, BBs, CCBs, and diuretics with colorectal cancer risk. Meta-analytic risk ratios (RRs) and corresponding 95% confidence intervals (95% CIs) were calculated using the inverse variance method. No overall significant associations with colorectal cancer risk were observed; ACEIs (5 studies) RR 1.05, 95% CI 0.91-1.23, ARBs (5 studies) RR 0.94, 95% CI 0.80-1.11, BBs (4 studies) RR 1.00, 95% CI 0.92-1.08, CCBs (4 studies) RR 1.02, 95% CI 0.88-1.18, and diuretics (6 studies) RR 1.02, 95% CI 0.90-1.17. There was considerable heterogeneity across studies, partly explained by differences in study design and location. When stratified by study location, there was significantly reduced colorectal cancer risk for ARB use in Asian populations (2 studies, RR 0.69, 95% CI 0.58-0.83). No significant colorectal cancer risk with ACEIs, BBs, CCBs, or diuretics was observed. ARB use may be associated with decreased risk of colorectal cancer in Asian populations, although additional studies in diverse populations are needed to confirm associations and help understand possible reasons for geographical differences.