Aging, comorbidities, and HIV
Ten years ago, few people over 50 were being treated for HIV; today this group makes up about one third of the HIV-positive population. This is due to more effective therapy, and also to more people being infected after age 50.
Dr. Alan Winston, with the Department of Medicine at Imperial College of London, cautions clinicians to be aware that the comorbidity profile for someone infected 20 years ago who may have experienced AIDS-defining illnesses and toxic early drugs is very different than someone recently diagnosed after age 50 and treated while their CD4 count is still high. As the population living with HIV changes, and fewer people have complex long-term treatment histories, comorbidities may decline. As an example, he discussed an Italian study presented at CROI in 2015, showing a declining prevalence of HAND.
Dr. Winston primarily presented the results of the POPPY study in the UK, which he leads, and the AgeHIV study in the Netherlands. Both look at comorbidities in adults aging with HIV, and both have carefully matched control groups of HIV-negative people with similar lifestyle characteristics.
Data from AgeHIV show significantly more hypertension, angina and heart attacks, liver disease, renal failure, and cancer in HIV-positive participants over 45 compared to matched controls (Shouten J et al, 2014). Patterns of comorbidities are similar to those for matched controls 10-15 years older. Similarly, POPPY shows higher rates of cardiovascular events with a trend towards more nervous system disease and respiratory disease. Dr. Winston notes that stroke is an emerging focus of concern. He posited that, since conditions like stroke are very rare in young individuals, some concerns may only emerge as the population grows older still.
One hypothesis suggests that increased inflammatory responses to HIV infection drive these outcomes. However, other factors may also play a role. An analysis comparing inflammatory biomarkers among people over 50 living with HIV from the POPPY and AgeHIV studies, to their carefully matched HIV- negative controls and to a group of Dutch blood donors over 50, showed both groups of study participants had much higher levels of the biomarkers than the bloodbank donors. This suggests that lifestyle factors are an important part of the equation. Even compared to matched controls, HIV-positive participants in POPPY have some lifestyle factors that increase their risk, such as higher rates of recreational drug use.
For HIV clinicians, management of lifestyle factors is key. Although no strongly evidence-based guidelines are available, the European AIDS Clinical Society guidelines do offer a lengthy list of appropriate screening criteria for those over 50. This requires an ongoing screening plan, since all recommended tests can not be accomplished in a single appointment. Dr. Winston also noted the REPRIEVE study, now underway in the US, which may provide insight into the use of statins to reduce cardiac risk.