Trabecular bone score assessed by dual-energy X ray absorption predicts vertebral fractures in HIV infected young adults

Introduction: Bone mineral density (BMD) is reduced in patients with human immunodeficiency virus (HIV) infection. Trabecular bone score (TBS) is an additional feature calculated by dual-energy X ray absorption (DXA) that measures texture inhomogeneity at lumbar spine level, providing an index of bone microarchitecture. However, its clinical value still needs to be fully addressed. Aims of the study were to assess BMD and TBS in a cohort of patients with HIV compared to a population of healthy subjects and to investigate the prognostic value of TBS in HIV infected patients. Method: Bone health was assessed by DXA in 165 patients with HIV infection (120 men, mean age 40 ± 7 years) and in 164 healthy subjects (53 male, mean age 37 ± 10 years). BMD was measured at level of lumbar spine (L1- L4), femoral neck and total hip. TBS was computed from the images of lumbar spine using machine proprietary software. Results: BMD at femoral neck level was similar in HIV infected patients and healthy subjects (p = 0.57), whereas BMD measured in total femur was lower in HIV infected patients compared to healthy subjects (p < 0.05). Although mean BMD in lumbar spine was similar between HIV infected patients and healthy subjects (p = 0.90), mean lumbar TBS was lower in patients with HIV infection compared to healthy subjects (p < 0.05). Age, sex and HIV infection resulted independent predictors of reduced TBS. In HIV infected patients age, sex and protease inhibitor duration resulted independent predictors of reduced TBS. TBS was a significant predictor of vertebral fractures during follow-up (p < 0.05). Conclusion: Patients with HIV infection have a significant reduction of TBS, a texture parameter related to bone microarchitecture that may provide skeletal information that is not captured from the standard BMD measurement.