Patients with type 2 diabetes treated with metformin as a monotherapy are at a decreased risk for cardiovascular mortality when compared with those on sulfonylurea monotherapy, according to a report in the Annals of Internal Medicine.
Dr. Nisa M. Maruthur and her associates conducted an update of a previous systematic literature review and meta-analysis to assess the comparative effectiveness and safety of metformin monotherapy and combination therapies including metformin with nonmetformin monotherapies in patients with type 2 diabetes. They focused on original, adult human experimental, and observational studies (Ann Intern Med. 2016 Apr 19. doi: 10.7326/M15-2650).
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Dr. Maruthur and colleagues identified a total of 19,423 articles, of which 234 were found to meet the study inclusion criteria. The majority of the included studies were randomized, controlled trials, with 98 assessing all-cause mortality and macro- and microvascular outcomes.
On the basis of consistent findings from two randomized, controlled trials including 3,199 total participants (ADOPT and SPREAD-DIMCAD), a lower risk for cardiovascular mortality was found for metformin monotherapy versus sulfonylurea monotherapy. For those on metformin monotherapy, 2 of the 1,454 patients had a fatal MI and 7 of 156 patients died from cardiovascular disease. Three of 1,441 patients on monotherapy with a sulfonylurea had a fatal MI and 11 of 148 patients died from cardiovascular disease.
The evidence from this systematic review supports current type 2 diabetes guidelines that recommend metformin as the first-line agent to treat adults, based on its beneficial effects on hemoglobin A1c, weight, and cardiovascular mortality versus sulfonylureas, as well as its relative safety profile, Dr. Maruthur of the department of medicine and epidemiology at Johns Hopkins University, Baltimore, and her coinvestigators said.
The study was funded by Agency for Healthcare Research and Quality. Several of the coauthors disclosed contracts with the funding source during the conduct of the study. The remaining coauthors disclosed no conflicts of interest.