An international study has found that AIDS progression and death in HIV-positive patients decreses by 28 per cent on early administration of antiretroviral treatment.
The study analysed information from more than 45,000 patients in Europe and North America, and combined data from 15 international cohorts.
The best moment to instate antiretroviral treatment has been the subject of debate for some time.
The immune system's CD4 cell count, which falls as HIV infection progresses, is one of the main tools for establishing a guideline cut-off point.
Present guidelines recommend waiting for the CD4 count to fall below 350 cells per millilitre in asymptomatic patients.
While many a time it has been suggested that initiating treatment earlier could improve outcome, the correct administration of the treatment has remained difficult for fear of the side effects associated with the drugs.
The study report, whose first author is Professor Jonathan Sterne of the UK-based University of Bristol, suggests that it is now possible to consider instating treatment earlier without unduly affecting the patient's quality of life with the aid of new families of drugs and new, less toxic combinations.
Data for the study were obtained from 21,247 patients who were followed up during the period prior to instatement of combined antiretroviral therapy, and 24,444 patients who were followed up from the beginning of treatment.
The researchers observed that waiting to administer the combined therapy until CD4 levels had fallen to between 251 and 350 cells per millilitre was associated with a 28 per cent higher rate of development of AIDS and death than beginning treatment when levels were between 351 and 450 cells per millilitre.
They revealed that the adverse effects of delaying therapy were directly linked to the drop in the CD4 count.
According to them, waiting to treat until the CD4 count was below those levels was also associated with a higher mortality rate at 13 per cent, though the effect on mortality was smaller than the combined effect on developing AIDS and death.
The new findings are expected to help doctors worldwide decide on the best time to begin antiretroviral treatment.
A research article on the study has been published in the online edition of The Lancet.