The development of new-onset type 2 diabetes associated with choosing a calcium channel blocker compared to a diuretic or beta-blocker

Objective: It has been acknowledged that patients who receive a beta-blocker or diuretic based regimen are at increased risk of developing new-onset diabetes. Recently, angiotensin-converting enzyme inhibitors (ACEls) and angiotensin receptor blockers (ARBs) have been shown to decrease patients' odds of developing new-onset type 2 diabetes. A number of large placebo-controlled multi-center trials in post-myocardial infarction and heart failure patients have shown the ability of renin-angiotensin-aldosterone system medications to reduce the onset of type 2 diabetes. Pharmacologic data has shown improved insulin sensitivity with ACEls and ARBs. Controversy persists regarding the influence of calcium channel blockers on the development of new-onset diabetes. Research design and methods: Two reviewers conducted a systematic literature search of Medline, EMBASE, CINAHL, and the Cochrane Library (1966 to December 2006) to extract a consensus of trial data involving calcium channel blockers versus diuretics or beta-blockers with an endpoint of new-onset type 2 diabetes. Studies were included if they were. randomized controlled trials versus routine treatment, not observational studies of clinical practice. A random-effects model was utilized. Subgroup and sensitivity analyses were conducted. Results: Out of 1721 trials, six meeting inclusion criteria were identified, including 99 006 patients. Calcium channel blockers were associated with a reduced incidence of new-onset type 2 diabetes (odds ratio 0.81; 95% confidence interval [CI] 0.730.90; p = 0.0001) compared with diuretic or betablocker therapy. The reduction in new-onset type 2 diabetes was maintained when a calcium channel blocker was compared to only thiazide diuretics (OR 0.86; 95% CI 0.75-0.99; p = 0.0346). The meta-analysis was limited by the varying definition of new-onset type 2 diabetes mellitus, as well as the potential for publication bias, which is a limit of any meta-analysis. Conclusions: Calcium channel blockers may be associated with reduced odds of developing new-onset type 2 diabetes compared to diuretics and beta-blockers.