Risk factors for osteonecrosis in HIV-infected patients: impact of treatment with combination antiretroviral therapy.

BACKGROUND

Osteonecrosis was increasingly associated with HIV infection in the 1990s. It is unclear whether its risk increases with the duration of HIV infection, the duration of combination antiretroviral therapy (cART) or both.

OBJECTIVE

To analyse factors associated with the rate of symptomatic osteonecrosis, particularly the relative impacts of the duration of HIV infection and the duration of cART, using the French Hospital Database on HIV, which comprises a large number of subjects with substantial follow-up.

METHODS

Poisson regression model was used to identify factors associated with the rate of osteonecrosis among patients enrolled in 1996-2002.

RESULTS

The study involved 56,393 subjects with a total follow-up of 229,031 person-years. Symptomatic osteonecrosis was diagnosed in 104 subjects with an incidence rate of 4.5/10,000 person-years. Multivariate analysis identified three factors associated with the rate of osteonecrosis: prior AIDS-defining illnesses [adjusted relative rate (RR), 3.1; 95% confidence interval (CI), 2.0-4.9], the CD4 cell nadir [RR, 1.6 (95% CI, 0.9-2.9) for CD4 cell count 50-199 cells/microl; RR, 1.8 (95% CI, 1.0-3.3) for CD4 cell count < 50 cells/microl; both relative to CD4 cell count > or = 200 cells/microl] and exposure to cART. Compared with unexposed patients, the RR of osteonecrosis ranged from 2.6 (95% CI, 1.2-5.9) in patients treated with cART for < 12 months to 5.1 (95% CI, 2.1-12.6) in patients treated for > or = 60 months.

CONCLUSIONS

Osteonecrosis appears to be a complication of both HIV infection and cART.