Trabecular bone score not lower in T2D
Patients with type 2 diabetes (T2D) may not necessarily have lower trabecular bone scores (TBS) than nondiabetics, a finding that contrasts with that of previous research, according to a study published in a poster at the recent meeting of the Asian Federation of Osteoporosis Societies (AFOS 2017), held in Kuala Lumpur, Malaysia.
“TBS is an attempt to measure quantitatively bone microarchitecture, which can be a measure of bone quality in the lumbar spine,” said study investigator Dr Yeap Swan Sim, a consultant rheumatologist from the Puchong Medical Specialist Centre in Selangor, Malaysia.
“Previous studies have found TBS scores to be significantly lower in subjects with diabetes mellitus which is in contrast to this study,” said Yeap and co-authors. [J Clin Endocrinol Metab 2015;100:475-482]
In this study, TBS was comparable between patients with T2D and those without (1.289 vs 1.327; p=0.087). The researchers noticed a correlation between age and TBS (p=0.009), as well as a lower TBS among patients with a prior history of fracture (median, 1.210 vs 1.327; p=0.001). [AFOS 2017, abstract PC23]
While there was no significant difference in lumbar spine bone mineral density (BMD) between patients with or without prior fracture, patients with a previous fracture had significantly lower femoral neck and total hip BMD (p<0.0001 for each comparison).
“TBS values were lower in patients who had a fracture compared with those who had not. In our population, this was the case despite BMD being similar in both the fracture and non-fracture group. So, the use of TBS is an additional measurement that may be able to detect patients with altered bone microarchitecture who may be at risk of fracture, despite similar BMD,” said Yeap.
Fracture Risk Assessment Tool (FRAX) scores also significantly differed between patients with and without T2D (median, FRAXmajor with TBS, 7.40 vs 3.40; p=0.007, FRAXhip with TBS, 2.45 vs 1.00; p=0.032, and FRAXmajor without TBS, 7.10 vs 4.20; p=0.016).
However, there was no significant difference between T2D and non-T2D patients in terms of FRAXhip without TBS (median, 2.00 vs 1.20; p=0.061).
“There were differences in the FRAX score calculated with and without TBS but the differences were small and may not be clinically significant,” said the authors.
The study compared 56 patients with T2D (mean age 67.4 years, median T2D duration 10 years) with 56 nondiabetic patients (mean age, 60.55 years) who had undergone BMD measurement between December 2008 and June 2017. Patients with conditions that could potentially affect bone and calcium metabolism or those on bone-affecting medications were excluded from the study. BMD did not differ between diabetic and nondiabetic patients.
“In other studies with T2D patients, they had lower TBS levels compared to non-T2D patients, which could be a marker of altered bone quality in T2D. This may explain the higher fracture risk in T2D patients without much difference in the BMD measurements. However, we did not show this difference in this study, which we think may be due to … non-T2D patients [being] younger than the T2D patients,” said Yeap.
As these results were from a single-centre study, Yeap says that there are plans to research this on a wider scale, though the current lack of TBS software at many institutions may impede this plan.