Doctors on Thursday published evidence backing calls for treating HIV-infected patients before their immune system crashes below a commonly-recognised threshold of damage inflicted by the AIDS virus.
Highly active antiretroviral therapy (HAART) began to overturn the automatic death sentence associated with AIDS after this powerful cocktail of drugs was introduced in 1996.
But a big question is when someone infected with the human immunodeficiency virus (HIV) should start to take the drugs.
Physicians have to balance the benefits of restoring immune defences against the risk of the treatment's side effects, which can be toxic.
There is no universal guideline for when HAART should be administered, but a common recommendation is to start the drugs when there are fewer than 200-250 CD4 cells -- key immune cells that are attacked by the virus -- per microlitre of blood.
Some researchers say this threshold is too low and lives can be saved if drugs are started sooner, although hard evidence to back this is sketchy.
In a paper published in The Lancet on Thursday, a team led by Jonathan Sterne of Britain's University of Bristol compared studies that followed more than 45,000 HIV-infected people in Europe and North America before and after the HAART era.
Those who began HAART when their CD4 count was below 350 cells per microlitre were 28 per cent likelier to develop AIDS or die prematurely than those who grasped the lifeline when their CD4 tally was 351-450 cells per microlitre.
The paper says these figures shift the pendulum in favour of starting treatment earlier, especially as new antiretrovirals have fewer side effects than before.
"In view of diminished concerns about toxic effects and resistance, our results suggest that 350 cells per microlitre should be the minimum threshold at which antiretroviral therapy is started," it says.
In a comment also published in the Lancet, South African AIDS specialists Robin Wood and Stephen Lawn cautioned against a one-size-fits-all recommendation.
Poor countries often have a limited range of HAART drugs available and have to make tough decisions about cost effectiveness, they said.
"The question of when to start (HAART) might have more than one right answer," they argued.
Last August, a panel of American doctors in the International AIDS Society (IAS) also spoke in favour of raising the threshold to 350 CD4 cells per microlitre or higher.
The benefits from controlling HIV earlier include lower incidence of lung, anal, head and neck cancers, cardiovascular disease and kidney and liver dysfunction, they said.