Although many older diabetes patients have good bone density scores, they are as prone to fractures as people with osteoporosis.…
For people over 65, doctors usually recommend a bone density test to look for signs of bone loss and osteoporosis, but whether those tests are of use in older people with type 2 diabetes has been a question, according to the researchers.
The study’s lead researcher, Ann V. Schwartz, an associate adjunct professor in the epidemiology and biostatistics department at the University of California, San Francisco said, “People with type 2 diabetes have a strange combination … they have a higher fracture risk and they have a higher bone density.”
However, she said, “we found that these tests work to predict fracture,” though the interpretation of the results needs to be different.
To assess the value of bone density tests in predicting the risk for fractures among diabetics, the researchers looked at two tests of bone strength: bone mineral density, which produces what’s called a T score, and the World Health Organization’s fracture risk algorithm, called a FRAX score.
“A T score of minus 2.5 or lower is generally considered osteoporotic and at high risk of fracture,” Schwartz said. “But if you have someone with type 2 diabetes who has a T score of minus 2, they have about the same fracture risk as a non-diabetic with a T score of minus 2.5,” she said.
Doctors should use bone density to screen older adults with type 2 diabetes, Schwartz said, “but they have to realize that the threshold they use to indicate high risk has to be raised.”
For the study, Schwartz’s team collected data on 9,449 women and 7,436 men who took part in one of three studies. All participants were in their 70s when their study began.
During almost 13 years of follow-up, 84 hip fractures and 262 other fractures were recorded among the 770 women with diabetes. Among 1,199 men with diabetes, 32 had hip fractures and 133 had other fractures during about eight years of follow-up, the investigators found.
The researchers noted that, among diabetics, fractures were more likely to occur even when bone density tests indicated that there was only a small risk for fracture.
“For a given T score and age, those adults with DM [diabetes mellitus] had a higher risk of fracture than those without DM, consistent with previous studies,” they wrote. “Participants with DM also experienced higher fracture rates at a given FRAX score than participants without DM.”
Because of this, according to the researchers, doctors should consider people with type 2 diabetes at risk for fractures even when bone density tests indicate that they don’t have osteoporosis and, therefore, have a lower risk for fractures. In addition, Schwartz said that she would start treating diabetic patients for osteoporosis if they had T scores of minus 2.
She noted that standard treatments for osteoporosis have not been studied in diabetics but that they appear to work. “In general, the treatments seem to be as effective in diabetics as in non-diabetics,” she said.
Published in the Journal of the American Medical Association, June 1, 2011