Multiregional trials are designed under the assumption that treatment effect applies to the entire target population, yet several factors may introduce geographic heterogeneity in treatment effect. We explored whether such variations exist in trials assessing the efficacy of glucagon-like peptide 1 receptor agonists (GLP-1RAs) in major cardiovascular events (MACE) in type 2 diabetes.
A systematic search of Medline and the Cochrane Library was conducted from inception until 30 June 2020. We included international randomized controlled trials comparing any GLP-1RA versus placebo, with MACE as a primary end point. Individual participant data were subsequently requested from the sponsor or through data sharing platforms. For each trial, we calculated hazard ratios (HRs) and their 95% CIs for MACE, subgrouped by region. We then performed a random-effects meta-analysis and conducted meta-regressions to assess the influence of predetermined variables of interest on treatment effect.
We included six trials including 45,426 patients. Baseline risk of MACE ranged from 2.9 per 100 patient-years in Southern Asia to 7.4 per 100 patient-years in Sub-Saharan Africa. HRs for MACE ranged between 0.25 (95% CI 0.05, 1.12) in Northern Africa to 0.98 (0.79, 1.22) in Western Europe. There was no significant subgroup difference across regions (P = 0.70). Baseline risk of MACE and indexes of development status (i.e., Human Development Index, gross domestic product) were independently associated with GLP-1RA efficacy.
This study does not suggest any regional heterogeneity of GLP-1RA efficacy in MACE. However, a higher baseline risk and lower development status were associated with a greater benefit of these drugs.
This article contains supplementary material online at https://doi.org/10.2337/figshare.26528158.
