Michael Carter for Aidsmap (20 September 2010)
The longer a patient taking HIV treatment maintains an undetectable viral load, the lower their risk of virologic rebound, Canadian investigators report in the online edition of the Journal of Acquired Immune Deficiency Syndromes.
“We found that once viral suppression was initially achieved, high levels of adherence were still needed for at least the first year. Over time, however, the risk of viral rebound decreased with maintained viral suppression irrespective of the level of adherence”, comment the investigators.
Nevertheless, the investigators emphasize that patients should aim to take all their doses correctly.
Treatment with combination antiretroviral therapy can extend the life expectancy of HIV-positive patients to near normal levels.
To get the maximum benefit from their treatment, it is necessary for patients to take their treatment correctly. The best outcomes are seen in individuals who take at least 95% of their doses. Adherence below that level has been associated with an increase in viral load and the development of drug-resistant virus.
However, Canadian researchers hypothesized that once initial suppression of HIV was achieved after starting therapy, lower levels of adherence would be needed to needed to maintain an undetectable viral load. This is because the amount of virus capable of reproduction diminishes with longer duration of suppression.
To test their theory, the investigators performed a retrospective study involving 1305 patients starting HIV therapy for the first time between 2000 and 2006.
Each month of continuous suppression of HIV lowered the risk of rebound.
At all levels of adherence, the longer HIV was suppressed, the lower the risk of rebound.
“Our results reinforce the message of to individuals that sustained and near perfect adherence increase the probability of long-term viral suppression, particularly critical at the earliest stages of treatment”, write the authors.
Nevertheless, they conclude that “because the resilience of HAART [highly active antiretroviral therapy] increases over time, it is possible that individuals remain fully suppressed even after missing some doses of medication."