(HealthDay)—Sulfonylureas as second-line drugs for type 2 diabetes are associated with an increased risk of cardiovascular and hypoglycemic events compared with remaining on metformin monotherapy or adding to metformin therapy, according to a study published online July 18 in The BMJ.
Antonios Douros, M.D., Ph.D., from Jewish General Hospital in Montreal, and colleagues assessed whether adding or switching to sulfonylureas is associated with an increased risk of cardiovascular and hypoglycemic events. Patients adding or switching to sulfonylureas (25,699 subjects) were matched in a 1-to-1 ratio with those remaining on metformin monotherapy based on multiple factors, including hemoglobin A1c and number of previous metformin prescriptions.
The researchers found that over a mean follow-up of 1.1 years, sulfonylureas were associated with an increased risk of myocardial infarction (hazard ratio [HR], 1.26; 95 percent confidence interval [CI], 1.01 to 1.56), all-cause mortality (HR, 1.28; 95 percent CI, 1.15 to 1.44), and severe hypoglycemia (HR, 7.6; 95 percent CI, 4.64 to 12.44) versus continuing metformin monotherapy. Switching to sulfonylureas was associated with an increased risk of myocardial infarction (HR, 1.51; 95 percent CI, 1.03 to 2.24) and all-cause mortality (HR, 1.23; 95 percent CI, 1.0 to 1.5) compared with adding sulfonylureas. There were no differences observed for ischemic stroke, cardiovascular death, or severe hypoglycemia.
"Continuing metformin when introducing sulfonylureas appears to be safer than switching," the authors write.
One author disclosed ties to pharmaceutical companies including Boehringer Ingelheim, which provided funding for the study.
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