GlaxoSmithKline Plc's Avandia diabetes pill increases the risk of bone fractures in diabetic women who take it, a company-funded study found.
Women taking Avandia, also known as rosiglitazone, had more than twice the chance of suffering fractures than those on generic diabetes pill glyburide and 81 percent more than those taking generic metformin, the researchers reported. More than half of the fractures occurred in the upper arm, hand or foot and three-quarters were in women who had experienced menopause. The trend wasn't observed in men.
"Fracture rates were higher in older women taking rosiglitazone or glyburide but not metformin,'' the researchers, led by Steven Kahn of the University of Washington in Seattle, wrote in an abstract of the study. No prior medical history or previous or continuing medication use could be identified as a potential risk factor for fractures, they said.
The finding is more bad news for Avandia, which was the world's best-selling diabetes pill until reports in medical journals this year suggested that the product increased diabetics' risk of heart attacks by more than 40 percent. Sales of the medicine fell by 22 percent in the second quarter as prescriptions declined by half.
London-based Glaxo, Europe's largest drugmaker, has said it disagrees with previous reports linking Avandia to heart attacks.
The bone fracture side effect first came to light last year as a preliminary finding of the 4,360-person ADOPT trial that investigated the drug's long-term effect on blood sugar. The researchers in that study analyzed data from 1,840 women and confirmed the increased risk today at the European Association for the Study of Diabetes meeting in Amsterdam.
Avandia may be linked to reduced bone formation in postmenopausal diabetic women, according to a separate 12-week study of obese, post-menopausal women newly diagnosed with diabetes done at Baskent University in Ankara and also presented today at the meeting. Data from studies of rodents also shows decreased bone formation, Ove Torring of the Karolinska Institute told doctors at a Glaxo-sponsored lecture on Sept. 17.