High survival odds seen when HAART used early and continuously

NEW YORK (Reuters Health) - Five-year survival probabilities of greater than 90% are attainable when highly active antiretroviral therapy (HAART) is started soon after HIV infection and used continuously, new research shows.

"We know of only one previous study that estimated survival probabilities for patients treated with HAART," lead author Dr. Ard van Sighem, from the University of Amsterdam in the Netherlands, and colleagues note. The findings from the current study are in agreement with those from the earlier study, which estimated a 3-year survival probability of at least 95.9% for patients treated early and continuously with HAART.

As reported in the October 17th issue of AIDS, Dr. Sighem’s team assessed the outcomes of 3724 HIV-infected patients who initiated HAART. During 12,503 person-years of follow-up, 459 of the patients progressed to AIDS and 346 patients died.

Between 1996 and 2000, a drop in HIV-related mortality from 3.8 to 0.7 deaths per 100 person-years was noted. In contrast, no change in non-HIV-related mortality was seen during this period.

In patients younger than 50 years, 5-year survival probabilities of greater than 90% were attainable provided that the CD4+ cell count was not too low when HAART was started and that such therapy was used continuously. For asymptomatic and symptomatic patients, the minimum CD4+ cell counts needed were 10 and 150 cells/microliter, respectively.

If HAART was delayed or not used continuously, these CD4+ cell thresholds had to be higher to achieve the same survival odds.

In patients with regular 4-week interruptions in HAART, the CD4+ cell count at the start of treatment had to be greater than 450 cells/microliter to achieve a survival probability above 90%. When HAART was delayed for 1 year from the time of treatment eligibility, a count of 110 cells/microliter was needed for this survival probability.

"Our model predicted that using HAART continuously is the best [treatment] scenario," the authors point out. "Deferring HAART for 1 year after becoming eligible for treatment and using continuous HAART thereafter is, according to our model, better than using interrupted HAART."

Still, for patients younger than 50 years, the actual difference in survival probabilities between the three treatment strategies was small, the researchers note. Therefore, deferring HAART in such patients due to toxicity or adherence concerns may be acceptable, they add.

AIDS 2003;17:2227-2236.