Early ART Start Linked to Bone Loss in HIV Patients
Compared with deferring therapy, early antiretroviral therapy initiation may increase the rate of bone loss in HIV patients, according to a study published in the Journal of Bone and Mineral Research.
Reduced bone mineral density (BMD) and increased fracture risk are both associated with HIV infection and antiretroviral therapy (ART). "Because the relative contributions of ART and untreated HIV to BMD loss are unclear, it is important to quantify the effect of ART on bone," explained lead author Professor Jennifer F. Hoy. Her team compared the impact of immediate ART initiation (CD4 >500 cells/μL) vs. deferred ART (to CD4 <350 cells/μL) on the change in BMD in the randomized START Bone Mineral Density substudy.
BMD was assessed yearly at the lumbar spine and hip via dual-energy X-ray absorptiometry (DXA); percent change in BMD by treatment arms was also calculated.
Of the total 399 patients, the median CD4 count was 642 cells/μL. ART was used for 95% of follow-up in the immediate ART group vs. 18% of the deferred ART group; the most common agents were tenofovir and efavirenz. Over the 2.2 years mean follow-up, the immediate ART arm demonstrated greater BMD declines vs. the deferred ART arm at the hip (–2.5% vs. –1.0%, 95% CI: –2.2 to –0.8; P<0.001) and at the spine (–1.9% vs. –0.4%, 95% CI: –2.2 to –1.0; P<0.001).
Declines in BMD were highest in the first year of ART, the authors noted. Spine BMD stabilized after the first year for patients in the immediate ART group, however, over the two years, there was progressive decline in hip BMD. After the first year, changes in BMD were similar between the two groups.
"No clinical, HIV-related, or ART characteristic predicted greater BMD loss in either group," noted Professor Hoy. HIV treatment guidelines currently recommend ART initiation at the time of diagnosis as the overall benefits of treatment for preventing transmission and adverse health outcomes outweigh the possible negative effects on BMD. More research, however, is needed to understand the long-term consequences of BMD reduction associated with ART.
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