HIV and comorbidity complications
Prof Andrew Carr – Head, HIV/Immunology/Infectious Diseases Unit, St Vincent’s Hospital, Sydney
HIV and Bone Disease
People living with HIV (PLHIV) have lower bone mineral density (BMD) and experience more fractures than the general population of similar age. Both HIV-infection and antiretroviral treatment (ART) for HIV contribute to BMD loss, along with traditional risk factors; the relative contributions of lifestyle factors, HIV and ART are unknown.
The effect of HIV alone and introduction of ART was evaluated in 400 patients in the START study (START BMD substudy) and revealed that initiation of ART results in greater declines in bone mineral density than deferring ART and declines were greatest in the first year of ART. No clinical, HIV-related, or ART characteristics predicted greater BMD loss.
Significant ART-induced bone loss slows after the first year of ART.
It is known that all ART drugs can increase BMD loss in HIV patients, but exposure to tenofovir disoproxil fumarate appears to have a significantly greater effect. In patients with low BMD, it was unknown whether switching tenofovir DF to another ART drug or treatment with a bisphosphonate is the more effective and safe option for increasing bone mineral density. A randomised trial (ZeST study) has now demonstrated that treatment with zoledronic acid was superior to switching the tenofovir DF.
Stored samples are available from these studies to further understand the role of ART in loss of bone.
HIV and Cardiovascular Diseases
Cardiovascular disease is one of the major causes of morbidity and mortality in people living with HIV, with a 2-fold increased risk when compared with the general population.
This elevated risk is likely due to a complex interplay between the increased incidence of traditional cardiac risk factors, the adverse effects of ART and the pro-inflammatory effects of HIV itself.
A number of projects are being undertaken to better understand the contributions of lipid abnormalities, chronic inflammation and platelet function in the observed increased risk of atherosclerosis and clinical CVD events.
Access to the Victorian HIV Service database which contains clinical and treatment characteristics of people who received HIV care through Fairfield Hospital/Alfred Hospital and a plasma sample repository (Victorian HIV Blood and Tissue Storage Bank) following Research and Ethics approval, underpins the research into HIV and comorbidities.