Meta-analysis of the impact of alpha-glucosidase inhibitors on incident diabetes and cardiovascular outcomes

BACKGROUND: Alpha-glucosidase inhibitors (AGIs) have been shown to reduce incident type 2 diabetes but their impact on cardiovascular (CV) disease remains controversial. We sought to identify the overall impact of AGIs with respect to incident type 2 diabetes in individuals with impaired glucose tolerance (IGT), and CV outcomes in those with IGT or type 2 diabetes. METHODS: We used PubMed and SCOPUS to identify randomized controlled trials reporting the incidence of type 2 diabetes and/or CV outcomes that had compared AGIs with placebo in populations with IGT or type 2 diabetes, with or without established CV disease. Eligible studies were required to have ≥ 500 participants and/or ≥ 100 endpoints of interest. Meta-analyses of available trial data were performed using random effects models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for incident type 2 diabetes and CV outcomes. RESULTS: Of ten trials identified, three met our inclusion criteria for incident type 2 diabetes and four were eligible for CV outcomes. The overall HR (95% CI) comparing AGI with placebo for incident type 2 diabetes was 0.77 (0.67–0.88), p < 0.0001, and for CV outcomes was 0.98 (0.89–1.10), p = 0.85. There was little to no heterogeneity between studies, with I(2) values of 0.03% (p = 0.43) and 0% (p = 0.79) for the two outcomes respectively. CONCLUSIONS: Allocation of people with IGT to an AGI significantly reduced their risk of incident type 2 diabetes by 23%, whereas in those with IGT or type 2 diabetes the impact on CV outcomes was neutral.