April 28, 2008 -- The "glitazone" diabetes drugs Actos and Avandia may double or triple the risk of broken bones after a year or two of use.
The finding comes from Swiss researchers who analyzed 12 years of data on U.K. diabetes patients. They compared the 1,020 patients who suffered some kind of fracture to 3,728 matched patients who did not break any bones.
Over the course of the study, most of the patients took several diabetes drugs. But those who refilled their Actos or Avandia prescriptions eight times or more -- about 12 to 18 months of use -- had nearly twice the fracture risk of other patients.
And those who refilled their Actos or Avandia prescriptions 15 times or more -- two or more years of treatment -- nearly tripled their risk of fracture, found Christophe R. Meier, PhD, head of pharmacoepidemiology research at University Hospital Basel, Switzerland, and colleagues.
"We found a very strong signal here for higher risk of fractures in people taking glitazones," Meier tells WebMD. "Our evidence fits together nicely with animal models and clinical reports suggesting that these drugs have a detrimental effect on bone. And we did not find any increased risk for other diabetes drugs, so all together, it looks like something really is going on here."
The Meier study, all by itself, looked at too few patients to prove anything. But University of Pittsburgh researcher Jane A. Cauley, DrPH, who has studied bone loss in people with diabetes, agrees with Meier that it adds to a growing body of evidence.
"These animal and laboratory studies show these drugs interfere with the cells that grow new bone," Cauley tells WebMD. "That there is basic research supporting this study is important."