Estimating the effect of antiretroviral treatment during HIV seroconversion: impact of confounding in observational data

HIV Med. 2003 Oct;4(4):332-7. doi: 10.1046/j.1468-1293.2003.00168.x.

Abstract

Objective: To assess whether treatment with antiretroviral drugs within the first 3 months of infection with HIV affects medium-term health outcomes.

Design and methods: Data from 20 cohorts in Europe and Australia were used Concerted Action on SeroConversion to AIDS and Death in Europe (CASCADE). Analysis was restricted to persons seroconverting in 1988-1998 who started antiretroviral treatment in the first 3 months or 1-2 years from seroconversion. The relationship between times to low CD4 count, AIDS and death and time of initiation of treatment was estimated using proportional hazards models.

Results: Seroconversion illness was more common in those who began antiretroviral treatment in the first 3 months (73%) than in those who started treatment within 1-2 years post-seroconversion (33%). Subjects receiving early antiretroviral treatment had times to AIDS and to CD4 counts <200 cells/microL that were intermediate between those of subjects starting treatment within 1-2 years and those of the subset of these subjects starting treatment within 1-2 years who also had a prior CD4 count of >350 cells/microL and no prior AIDS diagnosis.

Conclusions: On the basis of these analyses, the effect of antiretroviral treatment initiation during HIV seroconversion is uncertain. It may result in lower rates of progression compared with starting antiretroviral treatment at 1-2 years, but the early antiretroviral treatment group had a similar or even higher incidence of low CD4 counts and AIDS events than the group who started antiretroviral treatment within 1-2 years with CD4 counts over 350 cells/microL and no prior AIDS diagnosis. Estimates of the effect of early treatment are probably confounded with a number of factors, including, in particular, reasons for treatment initiation.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age of Onset
  • Anti-Retroviral Agents / therapeutic use*
  • Australia / epidemiology
  • CD4 Lymphocyte Count
  • Cohort Studies
  • Confounding Factors, Epidemiologic
  • Europe / epidemiology
  • Female
  • HIV Infections / drug therapy*
  • HIV Infections / mortality
  • HIV Seropositivity / drug therapy*
  • HIV Seropositivity / mortality
  • Humans
  • Male
  • Regression Analysis
  • Risk Factors
  • Survival Analysis
  • Survival Rate
  • Time Factors
  • Treatment Outcome

Substances

  • Anti-Retroviral Agents