Effect of baseline CD4 cell counts on the clinical significance of short-term immunologic response to antiretroviral therapy in individuals with virologic suppression

J Acquir Immune Defic Syndr. 2009 Nov 1;52(3):357-63. doi: 10.1097/QAI.0b013e3181b62933.


Background: Achieving virologic suppression is a clear therapeutic goal for patients receiving combination antiretroviral therapy (cART). However, the effects of immunologic responses, whether measured as CD4 count changes from baseline or CD4 counts at follow-up, in patients with virologic suppression, have not been clearly established.

Methods: Treatment-naive individuals aged > or =16 years, who initiated cART between 1998 and 2005 in participating cohorts of the ART Cohort Collaboration and achieved viral load < or =400 copies per milliliter 6 months after cART initiation, were included. We used Cox models to examine associations of CD4 change from baseline to 6 months, and absolute CD4 counts at 6 months, with subsequent rates of mortality and AIDS. Analyses were stratified by baseline CD4 count.

Results: Among 23,679 eligible participants, the median increase in CD4 count at 6 months, and the implications of these increases for subsequent mortality and AIDS, varied with baseline CD4 count. Mortality hazard ratios for increases of 0-50 cells per microliter, compared with >100 cells per microliter, were 1.87 (95% confidence interval: 1.28 to 2.73), 1.60 (1.13 to 2.28), 0.98 (0.58 to 1.65) and 1.24 (0.70 to 2.18) in participants with baseline CD4 cell count <50, 50-199, 200-349 and > or =350 cells per microliter, respectively. In contrast, hazard ratios for mortality or AIDS associated with absolute CD4 cell counts at 6 months were similar across all but the highest baseline CD4 cell count strata.

Conclusion: It is not possible to derive thresholds for change in CD4 count that define an adequate immunologic response in individuals receiving cART. Absolute CD4 counts at 6 months are a more useful measure of immunologic response and subsequent prognosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / administration & dosage
  • Anti-HIV Agents / therapeutic use*
  • CD4 Lymphocyte Count*
  • Cohort Studies
  • Drug Administration Schedule
  • Female
  • HIV Infections / drug therapy*
  • HIV Infections / immunology*
  • HIV Infections / mortality
  • Humans
  • Male
  • Middle Aged


  • Anti-HIV Agents