Chronic hemodialysis is associated with lower trabecular bone score, independent of bone mineral density: a case-control study

We measured trabecular bone score (TBS) in 98 patients on permanent hemodialysis (HD) and 98 subjects with similar bone mineral density and normal kidney function. TBS was significantly lower in HD patients, indicating deteriorated bone microarchitecture, independent of bone mass. This might partially explain the increased fracture risk in HD. Purpose: In the general population, trabecular bone score (TBS) was shown to predict fracture independent of bone mineral density (BMD). In end-stage renal disease patients on hemodialysis (HD), the value of TBS is beyond that of BMD in currently unclear. Our aim was to assess lumbar spine (LS) TBS in HD patients compared with subjects with normal kidney function matched for age, sex, and LS BMD. Methods: We assessed TBS and LS and femoral neck (FN) BMD in 98 patient on permanent HD (42.8% males; mean age 57.5 +/- 11.3years; dialysis vintage 5.5 +/- 3.8years) and 98 control subjects (glomerular filtration rate > 60mL/min) using DXA. We simultaneously controlled for sex, age (+/- 3years), and LS BMD (+/- 0.03g/cm(2)). Results: HD patients had significantly lower LS TBS (0.07 [95% CI 0.03-0.1]; p=0.0004), TBS T-score (0.83 SD [95% CI 0.42-1.24]; p=0.0001)) and TBS Z-score (0.81 SD [95% CI 0.41-1.20]; p=0.0001) than matched controls. TBS significantly correlated with LS BMD in both HD patients (r=0.382; p=0.001) and controls (r=0.36; p=0.002). The two regression lines had similar slopes (0.3 vs. 0.28; p=0.84) with different intercepts (0.88 vs. 0.98). TBS adjustment significantly increased the 10-year fracture risk from 3.7 to 5.3 for major osteoporotic fracture and from 0.9 to 1.5 for hip fracture. Conclusions: HD patients have lower TBS than controls matched for LS BMD, indicating altered bone microarchitecture. Also, the magnitude of TBS reduction in HD patients is constant at any LS BMD. Adjustment for TBS partially corrects the absolute 10-year fracture risk.