SAN DIEGO – Elderly diabetes patients who received initial sulfonylurea monotherapy had a 33% greater risk for cardiovascular events at 2 years compared with those who were started on metformin therapy, according to a retrospective medical database review of 8,656 patients aged 65 and older.
Cardiovascular disease events also happened sooner among the sulfonylurea patients, Ying Qui, Ph.D., reported on June 25 at the annual scientific sessions of the American Diabetes Association.
The study, funded by Merck Sharpe & Dohme, examined records from the GE Centricity Electronic Medical Records database for patients who received either sulfonylurea or metformin as their first diabetes drug during 2003-2007, remained on the drug for at least 90 days, and had no cardiovascular events recorded in the year prior to the prescription, reported Dr. Qui, who is with the company.
A total of 4,328 patients in each treatment group were included for analysis. They had a mean age of 49 years, and 48% were men. A propensity analysis controlled for factors that might have influenced the choice of prescribed medication. They found that the likelihood of having a CVD event in the subsequent 2 years was 14.8% in the sulfonylurea group versus 11.6% for those in the metformin group (hazard ratio 1.33, P < 0.001).
The sulfonylurea group had a significantly greater likelihood of developing both ischemic heart disease (7.1% vs. 5.3%) and congestive heart failure (3.4% vs. 1.9%). The incidences of myocardial infarction, stroke, transient ischemic attack, and peripheral arterial disease did not differ significantly between the two groups.
In the cohort of 6,096 patients with 3 years of follow-up, the sulfonylurea group continued to have a higher risk for CVD events, with a hazard ratio of 1.20. The time to first cardiovascular event was significantly shorter in the sulfonylurea group, with hazard ratios of 1.22 compared with metformin at 2 years and 1.17 at 3 years, Dr. Qui reported.
Male gender and older age was also associated with greater risk for CVD events, she said.