Bone Abstracts

Introduction: Lower bone mineral content (BMC) has been reported in HIV-infected children, as well as those on ritonavir-boosted lopinavir (LPV/r)-based antiretroviral therapy (ART). Older studies of children with HIV report increased bone resorption, but data with current antiretroviral regimens are limited.

Methods: This analysis presents data from the CHANGES Bone Study (Johannesburg, South Africa). Whole body (WB) BMC was assessed by dual-energy X-ray absorptiometry. BMC Z-scores adjusted for sex, age, and height were generated. C-telopeptide of type-1 collagen (CTx), procollagen type-1 N-terminal propeptide (P1NP), and osteocalcin were analyzed. Outcomes were compared between HIV-infected (N=219) and HIV-uninfected children (N=180), as well as between HIV-infected children previously randomized to switch to efavirenz (N=106) versus remain on LPV/r (N=113) (intent-to-treat).

Results: The 219 HIV-infected children (49% male) and 180 HIV-uninfected children (55% male) were 5–9 years of age (mean 6.7 years). HIV-infected children were on treatment for a mean of 5.7 years and mean CD4% was 37%; 94% had viral suppression (HIV-1 RNA <400 copies/ml). Mean WB BMC Z-score was lower in HIV-infected than uninfected children (−0.95 vs −0.79, P=0.05) as well as in children on LPV/r versus efavirenz (−1.20 vs −0.68, P<0.01). CTX (1.72 vs 2.05 ng/ml, P<0.01) and P1NP (584 vs 634 ng/ml, P<0.01) concentrations were lower in HIV-infected than uninfected children. Osteocalcin was also lower in HIV-infected children than uninfected children, although not significantly (64.1 vs 69.2 ng/ml, P=0.22). CTX (1.70 vs 1.75, P=0.5) and P1NP (585 vs 583, P=0.9) were similar in HIV-infected children on LPV/r versus efavirenz, but osteocalcin was higher in children on LPV/r than efavirenz (72.4 vs 55.6, P<0.01). Bone turnover markers were not strongly correlated with bone mass.

Conclusions: Compared to uninfected controls, HIV-infected children in South Africa had lower BMC and lower markers of bone resorption (CTX) and bone formation (P1NP) in contrast to older studies. Although children on LPV/r had higher bone formation (osteocalcin), bone mass was decreased compared those on efavirenz. Longitudinal studies with broader measures of bone turnover are needed to understand the impact of HIV and antiretroviral medications on the dynamics of bone modeling and remodeling during childhood.

Disclosure: The authors declared no competing interests.