Further reports of avascular necrosis (AVN) and changes in bone mineral density (BMD)

17 December 2000. Related: Conference reports, Side effects, HIV 5th Glasgow 2000.

Simon Collins, HIV i-Base

Further reports of AVN in HIV-positive patients on HARRT was presented in Glasgow. This subject was also covered in detail in following the Lipodystrophy workshop in the October issue of HTB.

Nathan Clumeck reported on five cases among the 1870 patients (0.2%) followed over the last 4 years since PI-based HAART became available. [1] Both femoral heads were involved in patients 1, 2, and 3, homolateral tibia, calcaneus and astragalus in patient 4 and one femoral head in patient 5. Other comorbid factors usually associated with AVN were present only in patient 1 (diabetes). Mean age of these five patients was 45 (range 34-66), none of whom had clinical manifestations of lipodystrophy, and only one had elevated triglyceride levels. Patients 1, 2 and 3 needed complete bilateral hip replacement. Pathological study of femoral head of patient 2 showed bone necrosis with fibrotic changes and macrophagic reaction. Follow-up of patient 4 is ongoing. Patient 5 recovered after PI were stopped.

The delay in diagnosis of AVN was noted and the study concluded that ‘clinicians must be aware of this rare but devastating complication of HAART that could benefit from switching to PI sparing regimen’.

A separate case study involving bilateral osteonecrosis of femoral heads in an AIDS patient on HAART was reported from the University of Erlangen-NÙrnberg. [2] This 36-year-old HIV-positive male patient reported on bilateral coxalgia for several weeks treated with analgesics including NSAIDs. Osteonecrosis of both femoral heads was diagnosed by magnetic resonance imaging (FICAT I right hip, II – III left hip). The more affected left hip showed transitoric osteoporosis and reactive arthritis with joint effusion. No microbial pathogens could be recovered by aspiration of joint fluid. Abnormal levels of lipids or antiphospholipid antibodies could not be detected.

Surgery was postponed due to weak health associated with other HIV-rlated complications – systemic CMV infection (bilateral retinitis, pneumonia, pancytopenia) and fluconazole-resistant oesophageal candidiasis. However, following succesful therapy, the pain of the left hip worsened and a fracture of the left femoral head was diagnosed, which was treated by a replacement of the left hip with endoprosthesis with excellent clinical outcome. Transient fever after surgery was treated successfully with antibiotics. This study concluded that hip replacement is a feasible treatment option even in advanced AIDS patients to regain full mobility and quality of life.

Preliminary results from a cross-sectional study from the Royal Free hospital, indicated a high prevalence of reduced bone density amongst patients at this London clinic. [3] Of the 158 Patients who responded to posters advertising the study and completed a questionnaire, 93 took part in the study and underwent DEXA scanning. Of these patients, 66% are male, 70% Caucasian and 48% gay men. Median baseline characteristics included: 5.5 years since diagnosis of HIV, age 39 and 87% antiretroviral therapy experienced. 35% were current smokers. Median BMI was 24.9 kg/m 2, CD 4 count 425 cells/mm3 and viral load 3.6 log copies/ml at the time of DEXA scan.

Prevalence of reduced lumbar spine density was 74% using the T score, (58% had SD between 1.0-2.5 below the mean peak density for sex and race matched controls, and 13% were >2.5), and 66 % using the Z score (49% had SD between 1.0-2.5 below the mean density for sex, race and aged matched controls and 11% were >2.5). T and Z scores btween 1-2.5 would be expected to average only 15% of the general population. A T score greater than 2.5 SD below the mean indicates an osteoporotic spine and would be expected in <1% of the general population.

Discussion points raised by the study recognised that neither the mechanism or the clinical significance was not known but that DEXA scans are an effective way to detect and monitor changes. Integrating baseline DEXA and subsequent monitoring of patients starting HAART would provide a more thourough indication of the rate of progression for both BMD and fat redistribution changes to provide both patients and clinicians with better information for guiding interventions (such as switching therapy).

References:

1. Gérard M, Hardy D et al – Avascular necrosis (AVN) in HIV-infected patient treated with highly active antiretroviral therapy (HAART). Poster P186. 5th Intl Congress on Drug Therapy in HIV Infection, Glasgow. 22-26 October 2000.e
2. P. L ùw , L. Schneider et al – Bilateral osteonecrosis of femoral heads in an AIDS patient on HAART. Poster 187. 5th Intl Congress on Drug Therapy in HIV Infection, Glasgow. 22-26 October 2000.
3. A.L. Moore, A, Vashist et al – Reduced bone mineral density in HIV positive individuals. Oral presentation and poster PL8.7. 5th Intl Congress on Drug Therapy in HIV Infection, Glasgow. 22-26 October 2000.