Osteonecrosis in HIV

In this chart review (Scribner AN et al. Osteonecrosis in HIV: A case-control study . J Acquir Immune Defic Syndr 2000 Sep 1; 25:19-25.), most HIV-positive patients with osteonecrosis had at least 1 established risk factor for the development of this disease.

A number of recent reports have cited cases of osteonecrosis (sometimes referred to as aseptic or avascular necrosis) occurring in HIV-positive patients. This case-control study investigated potential risk factors for this complication.

Cases of osteonecrosis were identified from 1984 through 1998 from a large teaching hospital and 2 large private outpatient practices in Dallas. For each case, 2 controls were selected at random from among HIV-positive patients seen in the same clinic or hospital on the same day the case patient was diagnosed with the disease. Charts of cases and controls were reviewed for demographic information, HIV-related data, and known potential causes of osteonecrosis such as corticosteroid use, alcoholism, hyperlipidaemia, and diabetes mellitus.

The authors identified 25 cases of osteonecrosis, of which all but 2 had been diagnosed in 1996 or later. During 1998, the incidence of osteonecrosis in the hospital-based clinic was 0.37%, greater than the reported incidence of 0.135% in the general population. The most common risk factors were hyperlipidaemia, alcohol abuse, exogenous corticosteroids, and a hypercoagulable state.

Although there were no significant differences in the distribution of any single osteonecrosis risk factor between cases and controls, cases were significantly more likely than controls to have 1 or more established risk factors for osteonecrosis (odds ratio 7.94; 95% CI, 2.11%-29.97%). Four of the cases had received megasterol acetate – an agent known to have corticosteroid-like activity – versus no controls (P=0.01). The groups did not differ in the overall use of PIs or other classes of antiretroviral drugs. Among particular agents, however, saquinavir was independently associated with osteonecrosis, a finding that the authors cautioned may be due to the small number of cases. Seven of the 25 patients with osteonecrosis required hip-replacement surgery.

Despite the fact that all but 2 of the cases in this study were diagnosed after the introduction of PIs, the authors conclude that most patients with osteonecrosis and HIV infection will have 1 or more established risk factors. Therefore, rather than being caused by antiretroviral therapy or HIV itself, osteonecrosis occurs more commonly in patients with HIV because established risk factors are more prevalent in HIV-infected patients. As with so many of the metabolic complications of HIV disease, what remains unclear is whether certain HIV therapies contribute indirectly to the development of some of these risk factors (e.g., through PI-associated hyperlipidaemia).

Ref: Scribner AN et al. Osteonecrosis in HIV: A case-control study . J Acquir Immune Defic Syndr 2000 Sep 1; 25:19-25.

Source: AIDS Clinical Care, January 2001.

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