Potential predictive factors of osteoporosis in HIV-positive subjects

Recent reports showed a high frequency of osteopenia/osteoporosis in HIV-infected subjects. Mechanism on the basis of this alteration is still unclear, as the direct effect of virus or of antiretroviral drugs. One hundred sixty-one consecutive HIV-infected outpatients aged 30-50 years, both naive and HAART-treated for >1 year, were included. An interview questionnaire was performed to establish prior pathological, toxic, epidemiological histories, medications intake, physical activity and eating habits. Blood and urinary tests were checked to exclude concomitant diseases, as were markers of bone metabolism and vitamin D3-metabolites. Each subject underwent to a lumbar spine and left hipbone mineral density by DEXA, using WHO criteria for diagnosis of osteopenia/osteoporosis. Radiologist was unaware if the subject was receiving HAART or not. For groups' homogeneity Chi-square, Fisher's exact and Student's t tests were used. Logistic regression analysis was used to find predictors of osteopenia/osteoporosis and linear regression model to find differences in bone mass density. The demographic characteristics of the 48 naive subjects and the 113 on HAART were comparable. Eighty subjects (49.7%) showed osteopenia/osteoporosis: 22 (45.8%) naive and 58 (51.3%) on HAART (P = 0.46). Independent predictors of osteopenia/osteoporosis were female gender (OR: 3.02, 95% CI: 1.26-7.25, P = 0.01 vs. male), older age (OR: 1.10, 95% CI: 1.01-1.20, P = 0.03, for each additional year), low body mass index (OR: 0.78, 95% CI: 0.68-0.91, P = 0.001 for each additional unit) and higher HIV-RNA levels at DEXA (OR: 1.97, 95% CI: 1.16-3.34, P = 0.01 for each additional Log(10)), whereas the use of HAART (OR: 2.61, 95% CI: 0.66-10.27, P = 0.17 vs. naive) and the alterations of markers of bone metabolism were not significantly related to osteopenia/osteoporosis. Similar findings were obtained using linear regression model analysis. HIV-infected subjects have a high frequency of osteopenia/osteoporosis. Traditional risk factors are predictive of osteopenia/osteoporosis also in HIV-subjects; the association with higher HIV-RNA levels can suggest a direct role of HIV itself in the occurrence of bone disease.