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During the first year after initiating antiretroviral therapy (ART), patients lose 2% to 6% of their hip and spine bone mineral density (BMD). Tenofovir disoproxil fumarate (TDF) is associated with a larger initial decline in BMD than other antiretroviral agents, and efavirenz (EFV) may reduce levels of active vitamin D metabolites. To assess whether vitamin D and calcium supplementation mitigates BMD loss in patients receiving these drugs, AIDS Clinical Trials Group researchers conducted a randomized, double-blind, placebo-controlled trial in treatment-naive patients initiating TDF/FTC/EFV (N=165).
The median baseline 25-hydroxyvitamin D level was 57 nmol/L. Participants assigned to supplementation received 4000 IU of vitamin D3 and 1000 mg of calcium daily. Forty-eight weeks after ART initiation, hip BMD had declined significantly less in the supplementation group than in the placebo group (median decline, −1.36% vs.−3.22%). Similar results were seen in lumbar spine BMD. Such benefits were seen in participants with higher baseline 25-hydroxyvitamin D levels (50–188 nmol/L) as well in those with lower baseline levels (25–50 nmol/L).
Overton ET et al. Vitamin D and calcium attenuate bone loss with antiretroviral therapy initiation: A randomized trial. Ann Intern Med 2015 Jun 16; 162:815. (http://dx.doi.org/10.7326/M14-1409)
Comment
This study's relevance is somewhat lessened by the fact that TDF/FTC/EFV is no longer a recommended initial regimen in the U.S. and by the likely upcoming approval of tenofovir alafenamide, which — at least in the short term — causes less bone mineral density loss than TDF (NEJM JW Infect Dis Jun 2015 and Lancet 2015; 385:2606). If vitamin D and calcium supplementation can be shown to mitigate BMD loss with other antiretroviral regimens, however, it may have an important role to play in preventing osteoporosis and fractures as our patients live longer. In addition, if supplementation has a similar benefit in resource-limited settings, where regimens containing TDF and EFV are widely used, this approach could prevent bone disease in HIV-infected patients globally.