P91 Hiv in scotland: predicting the number of people who are under cd4 monitoring and receiving antiretroviral therapy

Background/introduction The number of people living with HIV in Scotland has increased in recent years as a result of the widespread use of antiretroviral therapy, improvements in testing, inward migration and new infections. Since these increases are expected to continue, it is imperative that HIV specialist care services understand how the number of people requiring care is going to change over time. Aim(s)/objectives To predict the number of HIV positive individuals who are under CD4 monitoring (and thus in HIV specialist care) and receiving ART in Scotland for 2013–2020. Methods Using CD4 monitoring data collected in Scotland for 2007–2012 we develop a statistical model that groups the HIV infected population into several categories depending on their CD4 count and ART status. The model is based upon a Markov process which predicts the status of individuals in year i+1 from their status (category) in year i. Historical data is used to estimate the transition probabilities which are modelled using a multinomial trend model. Confidence intervals are calculated using boot strap procedures. Results By 2020 there will be a 54% increase in the number of individuals who are receiving ART and a 42% increase in the number of individuals under CD4 monitoring. Results for individual HIV risk groups predict increases of at least 34%, 77% and 35% for heterosexuals, people who inject drugs and men who have sex with men, respectively. Discussion/conclusion With such large increases in the number of people who are under CD4 monitoring and receiving ART, NHS boards will need to plan ahead to ensure they have adequate resources to treat those in need.