- Category: HIV Treatment
- Published on Tuesday, 22 November 2011 00:00
- Written by Liz Highleyman
HIV positive people who receive a timely diagnosis and start treatment with suppressive antiretroviral therapy (ART) are likely to lose less than a decade of life expectancy -- comparable to the effect of cigarette smoking -- according to a mathematical model described in the November 14, 2011, advance online edition of AIDS.
Effective combination ART dramatically reduced AIDS-related mortality starting in the mid-1990s. But people with HIV still have higher rates of non-AIDS-related chronic conditions such as cardiovascular disease and cancer, for reasons that are not yet fully understood.
HIV positive people who sustained severe immune suppression before achieving undetectable viral load on ART -- whether due to infection early in the epidemic when effective drugs were not yet available, or due to late diagnosis and poor access to care -- may have lingering health problems that contribute to increased mortality. But outcomes among people who are diagnosed promptly and start early treatment with today's state-of-the-art drugs have yet to be determined.
Fumiyo Nakagawa from the HIV Epidemiology and Biostatistics Group at University College London and colleagues form the U.K. and Denmark used a computer simulation to estimate life expectancy in a high-income industrialized country with good access to ART and healthcare in general. The model patient was an HIV positive gay man who was infected with drug-sensitive HIV in 2010 at the age of 30 and is not coinfected with hepatitis C.
- Assuming prompt HIV diagnosis -- a median 2.8 years after infection, with a median CD4 T-cell count of 432 cells/mm3 -- the projected median age at death was 75.0 years.
- This reflects a loss of 7.0 years of life due to HIV, on average, relative to a similar HIV negative man -- comparable to the effect of diabetes or cigarette smoking.
- A promptly diagnosed individual was estimated to start ART an average of 5.9 years after infection and remain on therapy for 39.1 years, with an 85% probability of at least 1 treatment interruption.
- Such a person would spend an average of 18.8 years on a first-line regimen, 7.2 years on a second-line regimen (required by 60%) and 6.0 years on third-line and subsequent regimens (required by 32%).
- A man with no ART interruptions gained an additional 1.5 years of life expectancy.
- The cumulative risk of death for such a person at 5 years after HIV infection was 2.3%, rising to 5.2% at 10 years.
- A promptly diagnosed man would have a 41% probability of developing at least 1 AIDS-related condition in his lifetime, but only 14% of deaths were due to AIDS-related causes.
- Assuming late HIV diagnosis -- with a median CD4 count of 140 cells/mm3, usually occurring after an individual develops symptoms -- life expectancy was 71.5 years.
- This reflects an average loss of 10.5 years of life due to HIV.
"If low rates of virologic failure observed in treated patients continue, predicted life expectancy is relatively high in people with HIV who can access a wide range of antiretrovirals," the study authors concluded. "The greatest risk of excess mortality is due to delays in HIV diagnosis."
The increased risk of death in the late diagnosis scenario was mainly due to a high death rate within the first 10 years after diagnosis, they elaborated in their discussion.
"[T]he effect on life expectancy after this period was more modest," they wrote. "This is due to the durable effects of ART, even in those who start ART when their CD4 count is low. However, late diagnoses can and should be prevented by increased access and uptake of HIV testing."
The researchers noted that they assumed a lifelong 1.5-fold increased risk of non-AIDS death compared with the general population, due to the presence of HIV infection itself. "Bearing in mind that most people are predicted to have viral suppression and high CD4 counts for most of their lives, this may well be a pessimistic assumption, resulting in underestimation of life expectancy," they suggested.
Investigator affiliations: HIV Epidemiology and Biostatistics Group, Research Department of Infection and Population Health, UCL Medical School, London, UK; Health Protection Agency, Colindale, London, UK; Copenhagen HIV Programme, University of Copenhagen, Panum Institute, Copenhagen, Denmark; Centre for Viral Diseases at Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
F Nakagawa, RK Lodwick, CJ Smith, et al. Projectedlife expectancy of people with HIV according to timing of diagnosis. AIDS (abstract). November 14, 2011 (Epub ahead of print).