The
advent of highly active antiretroviral
therapy (HAART) in the mid-1990s led to a dramatic reduction in morbidity
and mortality due to HIV/AIDS, but response
to antiretroviral therapy varies among individuals based on a number of factors.
As
reported in the December 15, 2007 Journal of Acquired Immune Deficiency Syndromes,
researchers with the Antiretroviral Therapy Cohort Collaboration analyzed 20,379
treatment-naive HIV-infected adults who started HAART in 12 cohort studies in
Europe and North America.
• Over 61,798 person-years of follow-up,
there were a total of 1844 AIDS-defining events and 1005 deaths from all causes.
• Individuals with a baseline
CD4 count < 25 cells/mm3 had persistently higher progression rates than those
with a baseline CD4 count > 350 cells/mm3 (hazard ratio for AIDS 2.3, for mortality
2.5, 4-6 years after starting HAART).
•
However, baseline CD4 cell count became less predictive of outcomes over time.
• The rate of AIDS was persistently higher
among individuals who had experienced an AIDS-defining event before starting HAART.
• Individuals with presumed
transmission via injection drug use had substantially higher rates of AIDS and
death throughout the follow-up period (hazard ratio for AIDS 1.6, for mortality
3.5, 4-6 years after starting HAART).
•
High HIV viral load was not a significant predictor of progression to AIDS or
death.
Conclusion
In
conclusion, the study authors wrote, "Compared with other patient groups,
injection drug users and patients with advanced immunodeficiency at baseline experience
substantially increased rates of AIDS and death up to 6 years after starting HAART."
The
present study adds to the accumulating body of evidence that starting therapy
before significant immune suppression - perhaps even above the 350 cells/mm3 threshold
recommended by recently updated U.S. and European treatment guidelines -- is associated
with better outcomes.
01/18/08
Reference Antiretroviral
Therapy Cohort Collaboration. Importance of baseline prognostic factors with increasing
time since initiation of highly active antiretroviral therapy: collaborative analysis
of cohorts of HIV-1-infected patients. Journal of Acquired Immune Deficiency
Syndromes 46(5): 607-615. December 15, 2007.
The
advent of 
