HAART became widespread in more-developed countries in 1996. However, there is insufficient data from individual studies to estimate the prognosis of people with HIV-1 infection starting HAART. The ART Cohort Collaboration, led by Matthias Egger from the University of Bern, Switzerland, was established to fill this knowledge gap.
The investigators analysed data on over 12,000 adult patients from 13 prospective studies from Europe and North America. The patients had not received antiretroviral therapy previously and started HAART with a combination of at least three drugs. 870 patients developed a new AIDS event and 344 patients died.
More advanced disease-as demonstrated by a low CD4 white blood cell count at the beginning of HAART-was strongly associated with the probability of progression to AIDS or death. Compared with patients starting HAART with less than 50 CD4 cells per microlitre, patients with a CD4 count between 50 and 99 per microlitre had around a 25% relative reduction in risk of AIDS or death; those with counts between 100 and 199 had around a 50% relative risk reduction, whereas patients with initial CD4 cell counts above 200 per microlitre had a relative risk reduction of around 80%. A blood concentration of the HIV-1 virus above 100,000 copies per millilitre at the start of therapy was also associated with a higher probability of progression to AIDS or death. Other independent predictors of poorer outcome were advanced age, HIV-1 infection through injection drug use, and a previous diagnosis of AIDS. Overall, the probability of progression to AIDS or death at 3 years ranged from 3% for patients in the lowest risk category for all prognostic variables, to 50% for patients at the highest risk.
Matthias Egger comments: "This study is important because it helps to define when exactly in the course of the infection HAART should be initiated. Unfortunately, almost 60% of patients in our study were late and started with a CD4 cell count below 200 cells or a viral load above 100,000 copies. In these patients the treatment would have been more effective had it been started earlier. We now need to address the reasons responsible for the delay in treatment in order to maximise benefit from current antiretroviral therapy".
Contact: Professor Matthias Egger, c/o Department of Social Medicine, University of Bristol, Canynge Hall, Whiteladies Road, BRISTOL BS8 2PR, UK; T) +44 (0)117 928 7387 or +44 (0) 117 962 8576 (home); F) +44 (0)117 928 7325; E) egger@ispm.unibe.ch
Journal
The Lancet