Potential Mediators for Treatment Effects of Novel Diabetes Medications on Cardiovascular and Renal Outcomes: A Meta-Regression Analysis

BACKGROUND: 

Prior research suggests clinical effects of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose cotransporter-2 inhibitors (SGLT2is) are mediated by changes in glycated hemoglobin, body weight, systolic blood pressure, hematocrit, and urine albumin-creatinine ratio. We aimed to confirm these findings using a meta-analytic approach.

METHODS AND RESULTS: 

We updated a systematic review of 9 GLP-1RA and 13 SGLT2i trials and summarized longitudinal mediator data. We obtained hazard ratios (HRs) for cardiovascular, renal, and mortality outcomes. We performed linear mixed-effects modeling of LogHRs versus changes in potential mediators and investigated differences in meta-regression associations among drug classes using interaction terms. HRs generally became more protective with greater glycated hemoglobin reduction among GLP-1RA trials, with average HR improvements of 20% to 30%, reaching statistical significance for major adverse cardiovascular events (ΔHR, 23%; P=0.02). Among SGLT2i trials, associations with HRs were not significant and differed from GLP1-RA trials for major adverse cardiovascular events (Pinteraction=0.04). HRs for major adverse cardiovascular events, myocardial infarction, and stroke became less efficacious (ΔHR, -15% to -34%), with more weight loss for SGLT2i but not for GLP-1RA trials (ΔHR, 4%-7%; Pinteraction<0.05). Among 5 SGLT2i trials with available data, HRs for stroke became less efficacious with larger increases in hematocrit (ΔHR, 123%; P=0.09). No changes in HRs by systolic blood pressure (ΔHR, -11% to 9%) and urine albumin-creatinine ratio (ΔHR, -1% to 4%) were found for any outcome. 

CONCLUSIONS: 

We confirmed increased efficacy findings for major adverse cardiovascular events with reduction in glycated hemoglobin for GLP1-RAs. Further research is needed on the potential loss of cardiovascular benefits with increased weight loss and hematocrit for SGLT2i.