Daniel Davis is a Research Training Fellow at the Institute of Public Health at Cambridge University and SpR in Geriatric Medicine at Oxford Radcliffe Hospitals.
It has recently become clear that HIV is increasingly affecting the older population. Notifications of new infections to the UK Health Protection Agency are rising in the over 50s, and this subgroup presents different characteristics compared to those typically associated with the HIV epidemic.
Of course, better treatments mean that life expectancy is now much greater in those with chronic infection, and so prevalence of HIV is increasing among those in their fifties and sixties. But this is not the area of concern.
Most clinicians consider HIV among men who have sex with men, as well as active sexually in sub-Saharan Africa. However, the pattern is different in the older population, where proportionally more new infections are in heterosexual men and women without a connection to Africa. This represents a cohort less concerned about unwanted pregnancy and less aware of public health messages about safe sex practices with a new partner. More worryingly, this population tends to present very late – often with an AIDS-defining illness.
10% of older persons with new HIV are dead within a year. More than age per se, much of this mortality is driven by the high proportion of late presentations; given a threshold of CD4 < 350 count/mm-3, 62% are eligible for immediate antiretroviral therapy (ART). Prompt use of ART is effective in this age group. Indeed, because the mortality is so high in the untreated group (46% died within a year), the magnitude of benefit (absolute risk reduction and so number-needed-to-treat) is greatest in the over-50s.
This serves as a reminder that any age group is at risk of HIV. Clinicians treating older persons need to consider HIV infection at a much earlier stage. Though treatments continue to be effective in this age group, there is much more scope for interventions for prevention and early diagnosis.