Diabetes Drug TZD Increases Fracture Risk
If you are a woman with type 2 diabetes and you are taking any of the thiazolidinedione (TZD) drugs, you may be at increased risk of experiencing a fracture. A new study has found that women who took TZDs for one year had a 50 percent higher risk of fracture than patients who did not take the drug.
TZD drugs include pioglitazone (Actos) and rosiglitazone (Avandia), two popular type 2 diabetes drugs that help regulate blood glucose levels by reducing insulin resistance and enhancing the body’s tissues to be more sensitive to the effects of insulin. This drug group also decreases the amount of glucose produced by the liver in people who have type 2 diabetes.
The significant increased risk of fracture is of concern given that older women are already at higher risk of osteoporosis and fractures related to this bone-thinning disease. The American Diabetes Association reports that 11.5 million women age 20 and older have diabetes, and that 12.2 million people—men and women—age 60 and older have the disease. Just slightly more than half of these older individuals with diabetes are women.
In the new study, researchers at Henry Ford Hospital conducted a retrospective study from January 2000 to May 2007 of 19,070 patients at their facility, including 9,620 women and 9,450 men. A total of 4,511 patients had filled at least one prescription for a TZD during the study period. After evaluating the medical records of the patients, the researchers found an increased risk for fracture among women who had used TZDs for about one year. They did not observe an increased risk for fracture among the men.
The results of this study are of particular concern because both insulin and type 2 diabetes themselves are also known to increase the risk of fracture. The addition of TZD to the equation appears to significantly heighten the chance of fracture among older women.
The researchers also noted that the fractures associated with the use of TZD tended to involve the upper extremity and distal lower extremity. Fractures related to osteoporosis typically involve the hip and vertebra.
TZDs are typically prescribed for people who have failed first-line therapy with metformin and sulfonylureas. Individuals given TZDs usually are at greater risk of complications associated with the disease. These drugs also have other side effects, including weight gain, abdominal obesity, edema, and exacerbation of congestive heart failure in some patients.
Given the high risk of fracture associated with the use of TZDs and the other problems linked to use of these drugs, women who have type 2 diabetes and who are taking TZDs should talk to their healthcare provider about optional therapy to treat insulin resistance.
American Diabetes Association
Henry Ford Hospital news release, Feb. 10, 2010