Trabecular bone score (TBS) provides valuable information regarding fracture risk that cannot be determined by bone mineral density assessments in individuals with type 2 diabetes (T2D) and reduced kidney function, according to study results published in Diabetes Research and Clinical Practice.
TBS is a novel bone assessment method that uses dual-energy x-ray absorptiometry images to evaluate bone microarchitecture quality. Studies have shown that the risk for bone fracture is elevated in individuals with chronic kidney disease (CKD), likely because of disruptions in bone microarchitecture, but the relationship between CKD and TBS in individuals with T2D has not yet been determined.
To evaluate this, the TBS values of trabecular and cortical bone were compared with the estimated glomerular filtration rates (eGFRs) in 100 individuals (50% women) with T2D. The average age of included individuals was 64.4±9.2 years. Individuals with a body mass index (BMI) of 15 to 35 kg/m2 and an eGFR ≥15 mL/min were included. Individuals with abnormal calcium metabolism, foreign bodies at the lumbar level, or a history of falls or traffic accidents were excluded. In addition, patients receiving vitamin D supplementation or other medications with a specific effect on bone metabolism in the year prior to the study were excluded.
TBS values ≥1.350 were considered normal, values between 1.200 and 1.350 were considered to be indicative of partially degraded bone, and values ≤1.200 were considered to be indicative of degraded bone. Participants were considered to have microalbuminuria if their albumin to creatinine ratio was ≥2.5 to <30 mg/mmol in men or ≥3.5 to <30 mg/mmol in women. Macroalbuminuria was defined as an albumin to creatinine ratio of ≥30 mg/mmol.
TBS values significantly correlated with age (P <.0001), BMI (P <.0001), systolic blood pressure (P =.002), total cholesterol (P =.007), low-density lipoprotein cholesterol (P =.008), and eGFR (P =.002). No correlation between TBS and albuminuria was observed. Individuals with an eGFR <60 mL/min had significantly lower TBS values than individuals with an eGFR ≥60 mL/min (1.246±1.254 vs 1.337±0.115; P =.013) after adjusting for sex and age. This correlation remained significant when adjusting for additional potential confounders (P =.046). No significant difference in total bone mineral density was found between the groups stratified by renal function.
These findings indicated that bone microarchitecture is an important additional assessment in evaluating bone strength in individuals with CKD and T2D. TBS may provide crucial information on bone quality and fracture risk irrespective of bone mineral density, and has been found to correlate significantly with eGFR.
A limitation to this study was the emphasis on individuals with moderate kidney dysfunction, as the results may not be relevant for individuals with more severe kidney disease. Future studies including individuals with a wider range of CKD and with larger sample sizes are warranted.
Lamacchia O, Sorrentino MR, Berti G, et al. Glomerular filtration rate is associated with trabecular bone score in patients with type 2 diabetes mellitus. Diabetes Res Clin Pract. 2020;164:108164.