High Rate and Progression of Low Bone Mineral Density in U.S. HIV Group

More than half of a contemporary U.S. HIV cohort had osteopenia or osteoporosis, and one-third of the group had a 5% or greater decline in bone mineral density (BMD) during four years of follow-up. Significantly more people with HIV than matched HIV-negative controls had osteopenia or osteoporosis.

Low BMD poses a risk of fracture, and numerous studies have found higher fracture incidence with HIV infection. To get a better understanding of low BMD prevalence and progression in a contemporary U.S. HIV cohort, SUN Study researchers conducted a two-part analysis of that group.

The SUN Study is an ongoing prospective cohort of antiretroviral-treated people in four U.S. cities. Participants in the U.S. National Health and Nutrition Examination Survey (NHANES) provided a general-population control group matched 1:1 to SUN Study members by age, sex, race and body mass index (BMI). Both groups underwent DXA scans to measure BMD, which the authors classified as normal, osteopenia (standard deviation 1 to 2.5 below young adult reference BMD), or osteoporosis (standard deviation >2.5 below young adult reference). The researchers defined substantial BMD decline as a ≥5% decrease from baseline after one to four years of follow-up at the femoral neck, total hip or lumbar spine.

The analysis focused on 653 SUN Study participants who had DXA scans and clinical data for analysis. The group had a median age of 41 years, 77% were men, 59% white, 29% black and 10% Hispanic. Among 79% of SUN participants currently taking antiretroviral therapy (ART), 89% had a viral load <400 copies/mL. At any of the three anatomic sites assessed, 51% of SUN members had osteopenia and 10% had osteoporosis. Multivariate logistic regression identified six independent predictors of osteoporosis: age >46 years (odds ratio [OR] 2.27, 95% confidence interval [CI] 1.26 to 4.07, P = .006), nonwhite race (OR 2.58, 95% CI 1.45 to 4.65, P = .001), BMI <22.8 kg/m² (OR 3.96, 95% CI 2.23 to 7.07, P ≤.001), being unemployed or retired (OR 2.16, 95% CI 1.16 to 3.94, P = .013), >1 year taking tenofovir (Viread) (OR 2.47, 95% CI 1.35 to 4.48, P = .003) and apolipoprotein E <4.8 mg/L (OR 1.97, 95% CI 1.10 to 3.59, P = .023). (Apolipoprotein E plays a role in bone metabolism.)

Comparing the 462 SUN participants with NHANES participants who had the same type of DXA scan, the researchers found a significantly lower mean T-score at the femoral neck in the SUN group (–0.81 versus –0.33, P < .001). Low femoral neck BMD proved significantly more prevalent in SUN than in NHANES (47% versus 29%, P < .001), as did prevalence of osteopenia (45% versus 28%, P < .001) and osteoporosis (3.5% versus 0.9%, P = .005).

The longitudinal analysis included 170 SUN participants with at least two years of ART experience and four years of BMD data. BMD remained stable or increased in 85% of participants at the femoral neck, in 84% at the total hip and in 83% at the lumbar spine. BMD decreased ≥5% in 15% of participants at the femoral neck, 15% at the total hip, 17% at the lumbar spine and 31% at any site. Female sex, current smoking and longer stavudine use were more frequent with ≥5% bone loss but not significantly more frequent. BMI of participants with substantial bone loss did not change significantly over four years.

The overall 61% prevalence of osteopenia or osteoporosis in this cohort with well-controlled HIV reflects similar findings in previous research. Prevalence of low BMD proved almost twice higher in HIV-positive SUN Study participants as in matched adults in a general-population cohort. In other study groups, as in this analysis, longer tenofovir use has been linked to low BMD. But the SUN Study appears to be the first to find an association between low BMD and unemployment or retirement, which may reflect lower socioeconomic status. The authors believe the 31% bone loss rate over four years justifies the need for ongoing bone monitoring of and possible clinical intervention with people with HIV. Current recommendations for evaluation and management of bone disease in people with HIV recommend FRAX assessment for 40- to 49-year-old men and premenopausal women with HIV, and DXA scanning for older people with HIV.