Risks associated with diabetes drug rosiglitazone may be higher than those with pioglitazone

Nov 24 2008

Older adults who take the diabetes medication rosiglitazone appear to have a higher risk of death and heart failure than those taking the related medication pioglitazone, according to a report in the November 24 issue of Archives of Internal Medicine.

In 1997, a new class of oral medications known as thiazolidinediones expanded the available options for diabetes treatment, according to background information in the article. These drugs offered several clinical benefits, including decreased insulin resistance, better control of blood sugar and, for some patients, a delay in beginning insulin therapy. Two agents in this class, rosiglitazone maleate and pioglitazone hydrochloride, were approved and marketed beginning in 1999. Not long after, it became apparent that these drugs had important adverse effects, including heart failure and heart attack. A black box warning was recently added to both drugs cautioning against their use in patients with existing heart failure.

Recent meta-analyses have suggested that the risks associated with rosiglitazone may be higher than those associated with pioglitazone. To compare cardiovascular outcomes and death rates between the two therapies, Wolfgang C. Winkelmayer, M.D., Sc.D., and colleagues at Brigham and Women's Hospital and Harvard Medical School, Boston, used medical claims data to study 28,361 patients older than 65 years who began taking either rosiglitazone or pioglitazone between 2000 and 2005. Of these, 14,260 (50.3 percent) began treatment with pioglitazone and 14,101 (49.7 percent) with rosiglitazone.

After an average of 380 days taking pioglitazone or 369 taking rosiglitazone, 1,869 patients died. After adjusting for other factors, individuals taking rosiglitazone had a 15 percent higher rate of death and a 13 percent greater risk of heart failure compared with those taking pioglitazone. However, there were no differences in heart attack or stroke risk between the two groups.

"This study confirms the safety concerns that have been raised for rosiglitazone compared with pioglitazone, which, in turn, also cannot be considered a very safe drug given its well-documented effect on the risk of congestive heart failure," the authors write. "Although previous studies have indicated that the increased risk with rosiglitazone use resides predominantly in cardiovascular outcomes, the present study suggests that differences in all-cause mortality [death] risk may be even more important to consider in elderly patients."

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