[Prevalence of low bone mass in individuals with HIV infection]

BACKGROUND AND AIMS

There are no population data on bone mass in individuals with HIV in Spain, adjusted for age and sex.

MATERIALS AND METHODS

Bone mineral density (BMD) data were obtained by dual X-ray absorptiometry in a cohort of individuals with HIV infection compared with cohort data from the general population in Spain and the United States of America.

RESULTS

Of 928 individuals (mean 46 years, 25% women), the prevalence of osteoporosis in the lumbar spine/femoral neck was 18%/5% in men, and 17%/10% in women, respectively. The rate increased from the age of 40 in men and from 50 in women (osteoporosis in 20% and 27%, respectively). BMD was lower than that observed in the general population in almost all age groups (mean, -6%; between 0%-11% lower compared to the Spanish cohort, and -8%; between 0%-14% lower than the American cohort).

CONCLUSIONS

Our cohort of individuals with HIV had a lower BMD in all age groups after adjustment for age and sex, compared with the general population. This fact must be considered when making recommendations.

Evaluation of the fracture risk assessment tool for determining bone disease and the impact of secondary causes of osteoporosis in people living with HIV

BACKGROUND

Among HIV-infected individuals, screening for bone disease is encouraged to assess reversible risk factors and plan therapeutic interventions.

OBJECTIVE

We assessed the usefulness of Fracture Risk Assessment (FRAX) tool to identify candidates for dual X-ray absorptiometry (DXA) scan, or individuals with bone loss progression. We further explored how secondary causes of osteoporosis are reflected on FRAX.

METHODS

Longitudinal study of 217 consecutive individuals (mean, 45.8 years, 24% females) included after DXA scan. FRAX was calculated without/with femoral neck bone mineral density (BMD), checking the box of "secondary osteoporosis" for all the individuals.

RESULTS

Low BMD was observed in 133/217 (61%) individuals, of whom 98.5% had not been selected as candidates for DXA by current FRAX thresholds. Specifically, 23% of individuals aged <50 had low BMD but none was candidate for DXA. Adding BMD data, FRAX results increased by 50-100%, with 2/217 individuals (1%) above the thresholds. Classical and HIV-related secondary causes of osteoporosis (observed in 98% overall) correlated with low BMD, modifying significantly FRAX results (HCV coinfection, +124%; longer time of HIV infection, +93%; longer time on antiretroviral therapy, +147%; tenofovir exposure +36%). Individuals with lower BMD and higher FRAX results at inclusion had less bone decline in a follow-up DXA after a median of 3.5 years.

CONCLUSIONS

Currently recommended FRAX thresholds are not useful to select candidates for DXA scan, which could delay its performance in a population with a high prevalence of secondary factors for low BMD. Classical and HIV-related factors alter BMD and fracture risk estimation.

Increased prevalence of asymptomatic vertebral fractures in HIV-infected patients over 50 years of age

The prevalence of asymptomatic vertebral fracture in HIV-infected patients over 50 was 20%, associated with older age, male sex, longer time since HIV diagnosis, and tubular renal alterations. Vertebral fractures were independent of osteoporosis at lumbar spine, and were not predicted by the use of the FRAX equation.

PURPOSE

Vertebral fractures (VF) are the hallmark of osteoporotic fractures. Our objective was to determine the prevalence of asymptomatic VF and associated factors in HIV-infected patients over 50 years, and the role of FRAX equation.

METHODS

In a cross-sectional study, a diagnosis of VF was established by the semiquantitative method of Genant in thoracic and lumbar radiographs. Simultaneously, a dual X-ray absorptiometry (DXA), bone and kidney-related analytical, calcium intake, physical exercise, HIV-related factors, and FRAX estimation were evaluated.

RESULTS

Overall, 128 patients (35 women, 27%) were included. Mean age was 57 years. Hypophosphatemia and tubular renal dysfunction were observed in 13 and 21%. DXA scan showed osteopenia and osteoporosis at hip in 65 and 7% of patients, and in spine in 39 and 34%, respectively. VF were observed in 26 patients (20%), with a trend to be associated with lower serum phosphate, increased alkaline phosphatase, and with lower daily calcium intake. In a multivariate analysis, older age (OR 1.2 per year; 14% of VF at 50-55; 44% at 65-70), male sex (26 vs 6%), longer time since HIV diagnosis, and renal and tubular dysfunction were the associated factors. VF were not related with osteoporosis at lumbar spine, and could not be predicted by the FRAX equation.

CONCLUSIONS

The prevalence of asymptomatic vertebral fractures is high in HIV-infected patients older than 50 years, and is not identified by the presence of osteoporosis in spine neither predicted by the FRAX equation. Spine and lumbar X-rays should be routinely performed in this aging population.