What Causes Low Bone-Mineral Density in HIV-Infected Patients?

Carlos del Rio, MD

Is it the virus, the drugs, or other factors?

Osteopenia and osteoporosis are common among HIV-infected patients, increasing their risk for fractures. Although antiretrovirals were initially suspected as the cause, the pathogenesis is probably multifactorial and likely includes traditional risk factors such as smoking, vitamin D deficiency, and hypogonadism. To investigate this issue, researchers in Amsterdam evaluated a cohort of HIV-infected individuals aged ≥45 on antiretroviral therapy and matched HIV-uninfected controls recruited from a sexual health clinic (n=581 and 520, respectively). Participants underwent dual-energy x-ray absorptiometry scanning at baseline and then every 6 months.

HIV-infected individuals had a lower median body weight and were more likely to be injection-drug users, to be black, and to have hepatitis B or C virus infection; their median nadir CD4 count was 170 cells/mm3. During the year preceding enrollment, their median CD4 count was 565 cells/mm3, 88.5% had viral loads <200 copies/mL.

The prevalence of osteoporosis or osteopenia was significantly higher in HIV-infected patients than in HIV-uninfected ones (13.3% vs. 6.7%). After adjustment for age, sex, menopausal status, and race, HIV infection was significantly associated with lower bone mineral density (BMD) in the femoral neck and the hip but not in the lumbar spine; after additional adjustment for body weight, HIV infection was no longer associated with low BMD in the femoral neck. The latter association was attenuated in the hip and became nonsignificant with adjustment for smoking.

CITATION(S):

Kooij KW et al. Low bone mineral density in patients with well-suppressed HIV infection is largely explained by body weight, smoking and prior advanced HIV disease. J Infect Dis 2014 Sep 1; [e-pub ahead of print].