BMD, TBS higher in elderly hip fracture patients with vs without T2DM

When presenting with hip fractures, both bone mineral density (BMD) and trabecular bone score (TBS) are higher in elderly type 2 diabetes mellitus (T2DM) patients with severe osteoporosis, according to a recent Singapore study.

“Our study adds to the growing body of literature on the characteristics of BMD and TBS in T2DM patients, especially in older patients with severe osteoporotic hip fractures of different ethnic backgrounds with well controlled or poorly controlled T2DM,” the researchers said.

The retrospective, cross-sectional analysis included 753 elderly hip fracture patients enrolled from the Changi General Hospital. Majority of the study participants were women (n=509), of whom 85 had well controlled T2DM, 74 had poorly controlled disease, and 350 were non-T2DM controls. Of the 234 men, 36 had well-controlled T2DM, 36 had poor control over the disease, and 162 did not have T2DM.

At fracture presentation, TBS was slightly higher among women with well-controlled disease as compared with their poorly controlled counterparts, though both scores nevertheless indicated slight degradation. This was reflected in BMD in the lumbar spine, which was lower in women with poor T2DM control. [PLoS One 2020;15:e0241616]

In men, TBS and BMD at the lumbar spine, total hip, and femoral neck were all numerically better in those with poor disease control than in well-controlled comparators, but failed to reach significance.

Notably, in both men and women with hip fracture, TBS and BMD at all examined sites were much better than in non-T2DM controls.

Multivariate analysis revealed that the effect of T2DM seemed to be stronger in women. TBS, for example, remained significantly greater in women with well-controlled T2DM relative to non-T2DM controls even after complete adjustments for demographic factors, amputation, kidney function, and lumbar spine BMD (p=0.004). The same was true for BMD at all examined sites.

In contrast, well-controlled T2DM had no significant and independent effect on either TBS or BMD among men.

Both men and women with poorly controlled T2DM likewise saw no significant difference in TBS relative to their non-T2DM comparators. BMD at all sites, however, were higher among women patients despite poor disease control. Men with poor T2DM control also had better total hip BMD than controls.

“Taken together, bone quality assessment in T2DM patients remains a complex issue,” the researchers said. “Differences in T2DM disease control and complication, together with age and body mass index may contribute differently to the results of current bone quality measurement differences.”

“These differences were most significant in elderly T2DM hip fracture patients with poorly controlled T2DM and would be important for clinicians who are looking after elderly T2DM patients to be aware of,” they added.

Future studies are needed to better understand the mechanism of action of glycaemic control on bone health, as assessed by TBS and BMD, among diabetics, as well as the potential impact of other factors, such as ageing, osteoporosis, and diabetes medication.