Objective: To determine how long highly active antiretroviral therapy can be deferred in HIV-1 infected persons.
Design: Observational cohort study of HIV-1 infected men at four academic centers in the USA.
Outcome: Progression to clinical AIDS or to CD4 cell counts < 200 x 10(6)/l in the absence of antiretroviral therapy among HIV-1 infected men.
Results: No participant with a CD4 cell count between 201 x 10(6) and 350 x 10(6)/l and having < 20 000 copies/ml of HIV RNA progressed to clinical AIDS within 1 year. In men with > 350 x 10(6) CD4 cells/l and < 60 000 copies of HIV RNA/ml there were also no instances of progression to clinical AIDS within 1 year. No participant with < 10 000 copies HIV RNA/ml and between 201 x 10(6) and 350 x 10(6) CD4 cells/l had a decrease in CD4 cells to < 200 x 10(6)/l within 1 year. In men with baseline CD4 cell counts > 350 x 10(6)/l and HIV RNA < 30 000 copies/ml, only 3% had a decrease in CD4 cell count to < 200 x 10(6)/l within 1 year.
Conclusion: This analysis supports recommendations to defer therapy in HIV-1 infected individuals with CD4 cell counts > 350 x 10(6)/l and HIV RNA < 60 000 copies/ml and in persons with CD4 cell counts between 201 x 10(6) and 350 x 10(6)/l and < 20 000 copies/ml HIV RNA. Up to 79% of persons with > 350 x 10(6) CD4 cells/l and 29% with CD4 cell counts between 201 x 10(6) and 350 x 10(6)/l may, with close monitoring, safely defer therapy.