Calcaneal Quantitative Ultrasonography and Urinary Retinol-Binding Protein in Antiretroviral-Treated Patients with Human Immunodeficiency Virus in Uganda: A Pilot Study

Background: Data on bone health and renal impairment in people with human immunodeficiency virus (HIV) in resource-limited settings are limited. The primary aim of this study was to investigate the potential role of calcaneal quantitative ultrasonography (QUS) in predicting bone mineral density (BMD) reduction in a population of Ugandan HIV-infected individuals receiving long-term antiretroviral therapy; the secondary end point was to assess the prevalence of proximal tubular dysfunction and the correlation between elevated urinary retinol-binding protein-urinary creatinine ratio (uRBP/uCr) and reduced BMD. Methods: We conducted a cross-sectional study at the Infectious Diseases Institute, Kampala, Uganda. We included 101 HIV-infectedadults who had been receiving continuous antiretroviral therapy for≥10 years and had undergone dual-energy x-ray absorptiometry (DXA) during the previous 12 months. All patients underwent calcaneal QUS evaluation and urine sample collection. Results: DXA BMD measurements were significantly associated (P<.01) with calcaneal speed of sound, broadband ultrasound attenuation, and QUS index. Forty-seven individuals (47%) had abnormal uRBP/uCr values. A significant inverse correlation was observed between uRBP/uCr and DXA T scores (lumbar [P=.03], femoral neck [P<.001], and total hip [P=.002]). Conclusions: Calcaneal QUS results showed a moderate correlation with DXA outputs. The identified high prevalence of subclinical tubular impairment also highlights the importance of expanding access to tenofovir disoproxil fumarate-sparing regimens in resource-limited settings.