Longer type 2 diabetes duration increases fracture risk, study reports

Women who have had type 2 diabetes for longer than 10 years are more likely to experience major osteoporotic fractures (MOF), according to Canadian researchers.
The women involved in this new study also had an increased risk of hip fractures, and the scientists added these figures have been underestimated by the World Health Organisation’s Fracture Risk Assessment (FRAX) tool.
Type 2 diabetes is known to increase the risk of MOF by 20 to 30 per cent, and increase fracture risk by 70 to 80 per cent, according to University of Alberta researchers.
In this study, they wanted to assess if the FRAX tool, which is calibrated for the general population, calculated this risk in patients with type 2 diabetes.
“While FRAX is known to underestimate the risk of fracture in women with type 2 diabetes, we demonstrated that it is most severely miscalibrated for both MOF and hip fractures in those with 10 years or longer duration of diabetes,” said study author Dr. Sumit Majumdar.
The 57,800 women studied in this new analysis had previously enrolled in the Manitoba Bone Mineral Density (BMD) cohort, all of whom were older than 40 years. 8,840 had type 2 diabetes and had undergone hip dual emission X-ray absorptiometry (DXA) measurements from 1996 to 2013.
The researchers calculated FRAX scores according to BMD at the femoral neck and evaluated the women for an average of seven years.
In the 31.4 per cent of women whose duration of diabetes was longer than 10 years, there was an increased risk of MOF. There was no increased risk for diabetes duration of less than 10 years.
Additionally, there were increased risks for hip fracture across all diabetes durations. Even patients with new-onset diabetes had a statistically significant risk.
Majumdar’s team found that FRAX scores significantly underestimated these risks: the risk of fracture for patients with diabetes duration longer than 10 years was 24 per cent greater than predicted; for hip fractures, the ratio of observed was predicted was nearly double.
“The clinical implications of this study are that FRAX underestimates risk, especially for hip fractures, in patients with long duration of diabetes, and raises the question of whether type 2 diabetes of long duration should be considered a red flag for greater attentio,” said study author Dr William Leslie.
The findings appear in the Journal of Clinical Endocrinology and Metabolism.