Bone mineral density abnormalities in HIV infected patients and HIV negative respondents at Mbagathi Hospital using calcaneal quantitative ultrasound

Abstract

Background: Osteoporosis is a systemic skeletal disorder characterized by low bone mass and micro-architectural deterioration of bone tissue, with a consequent increase in bone fragility and fracture. Use of Highly Active Anti-Retroviral Therapy (HAART) has been associated with prolonged survival and consequently with an increase in the prevalence of decreased bone mineral density. Quantitative Ultrasound (QUS) is gaining popularity as an appropriate tool for determination of bone mineral density profiles in resource- poor settings.

Objectives: To determine and compare the difference in the prevalence of Bone Mineral Density (BMD) abnormalities using quantitative calcaneal ultrasound between HIV infected patients on a TDF based first-line regime for at least one year, HAART-naive HIV positive patients in Mbagathi Comprehensive Care Clinic (CCC) and a HIV negative control group seen at the Mbagathi Voluntary Counselling and Testing Centre (VCT). To describe the occurrence of traditional risk factors associated with decreased BMD in the above populations (oral corticosteroid use, smoking, alcohol, previous bone fracture, body mass index and physical inactivity).

Methods: This was a cross-sectional comparative group descriptive study of HIV positive adult patients on TDF based first-line regime (exposed), HIV positive HAART- naive adult patients (unexposed) and HIV negative adult group (control) at Mbagathi Hospital. Random sampling was used to recruit 315 participants (105 in each arm). An interviewer administered questionnaire was used to document risk factors for low BMD. Quantitative ultrasound bone mineral density was done using a heel ultrasonic gel- coupled QUS system, the Sunlight Mini Omni (Beam Med Ltd, Israel).

Results: The prevalence of osteoporosis among HIV positive respondents on HAART was significantly higher (58.1%) compared to HIV positive respondents not on HAART (32.6%) (Z-test p-value = 0.001) and HIV negative respondents (9.3%) (Z-test p-value = 0.001). Older patients had lower levels of BMD (i.e. more negative BMD. p-value = 0.032). HIV positive respondents on HAART had lower BMI than HAART naïve and HIV negative individuals (23.6%, 24.8% and 26.1% respectively). There was a significant positive correlation between T-score and BMI (p-value 0.043). There was no significant correlation between Tscore and the other traditional risk factors (oral corticosteroid use, smoking, alcohol use, history of bone fractures and physical activity).

Conclusions: Use of TDF based HAART regimes is associated with higher rates of osteoporosis compared to HAART naïve and HIV negative populations which may be partly mediated by lower Body Mass Index (BMI).