BASEL, Switzerland, April 30 (UPI) -- Swiss researchers are calling for more study to determine if fractures are linked to a class of drugs for diabetes.

Their study, published in the Archives of Internal Medicine, finds patients taking rosiglitazone and pioglitazone had approximately double or triple the odds of hip and other non-spine fractures than those not taking these drugs.

Study leader Dr. Christian Meier, of University Hospital Basel, in Switzerland, matched for age and gender 1,020 diabetic patients with fractures diagnosed by British doctors from 1994 to 2005 with up to four diabetic patients without fractures of the same physician -- for a total of 3,720 controls.

Fracture odds increased for those taking the drugs for approximately 12 to 18 months and the risk was highest after two or more years of therapy.

"This analysis provides further evidence of a possible association between long-term use of thiazolidinediones and fractures, particularly of the hip and wrist, in patients with diabetes mellitus," the study authors say in a statement. "No such effect was seen for other anti-diabetic drugs."

The findings, although consistent with recently reported data from a randomized trial, are based on relatively few thiazolidinedione-exposed patients and need to be confirmed by additional observational studies and by controlled clinical trials, the researchers said.