TORONTO — The risk for hip fractures appears to be elevated in elderly men and women with diabetes, Dr. Lorraine L. Lipscome reported in a poster at the joint annual meeting of the Canadian Diabetes Association and the Canadian Society of Endocrinology and Metabolism.
Whereas previous studies have documented an association between type 1 diabetes and osteoporotic fractures, the data on patients with type 2 diabetes have conflicted. Those studies have mostly been small and limited to women. Moreover, bone density is typically normal or high in type 2 diabetes, whereas it is reduced in type 1, leading some to believe that people with type 2 diabetes are somehow “protected,” said Dr. Lipscome, of the University of Toronto.
In a retrospective cohort study using population-based Ontario health care databases from 1994 to 2003, researchers compared the risk of hip fractures between individuals older than 65 years of age with and without diabetes. After excluding those with prior hip fractures or hip replacements and those on oral corticosteroid treatment, the study population comprised 207,252 diabetics and 414,504 nondiabetics, with an overall mean age of 71.7 years. Information about diabetes type was not available, but it was presumed that most were type 2 because of the age group involved, Dr. Lipscome said in an interview.
After a mean of 6.1 years, the risk for hip fractures was significantly higher among those with diabetes, at 7.21 per 1,000 person-years, compared with 6.15 per 1,000 person-years among those without diabetes.
Compared with nondiabetics, those with diabetes had more comorbidity, were less likely to have had a bone mineral density test, and were more likely to be taking drugs that affected fall risk and bone density.
Women had a significantly higher risk for fracture than did men, but diabetes increased the risk in both genders, with hazard ratios of 1.22 for men and 1.19 for women. The increased risk remained significant (1.18 in men and 1.11 in women) after adjustment for age; comorbidity; prior stroke; visual impairment; neuropathy; amputation; treatment with nitrates, statins, anticonvulsants, inhaled corticosteroids, thiazides, or fall-promoting medications; history of a bone mineral density test; estrogen treatment in women; and income quintile in men, Dr. Lipscome reported.
Insulin use among the patients with diabetes increased the fracture risk, with hazard ratios of 1.34 in women and 1.64 in men, compared with those not using insulin.
Until the phenomenon is better understood, bone fracture risk assessment and enhanced prevention strategies are warranted in all patients with diabetes, she said.