A new observational study has found that asymptomatic, antiretroviral-naïve HIV patients had better survival rates the earlier they were treated. A similar study in the Lancet two weeks ago came to a similar conclusion, suggesting patients should initiate treatment before CD4 counts fall below 350. The study published Thursday suggests even earlier treatment may be beneficial.

The new study analyzed two groups of HIV patients from the United States and Canada during 1996-2005. Among the first group of 8,362 HIV patients, 2,084 initiated antiretroviral therapy when their CD4 counts were 351-500 cells/cubic millimeter, while 6,278 patients with similar counts delayed therapy until counts fell to 350. Among the delayed-therapy group, the risk of dying was 69 percent higher compared with the early-therapy group.

In another analysis involving 9,155 patients who had CD4 counts of more than 500, 2,084 initiated therapy within six months, and 6,935 deferred therapy. Among 3,881 delayed-therapy patients whose CD4 counts dropped, 539 initiated therapy within six months of a CD4 count of 500 less. The risk of death for delayed-therapy patients was 94 percent higher compared to early-treatment patients.

The new analysis is based on observational research, not a controlled, prospective study, so it does not provide a definitive answer as to when patients should initiate therapy, Dr. Paul E. Sax, clinical director of infectious diseases at Brigham and Women's Hospital in Boston, wrote in an editorial accompanying the study.

The study, "Effect of Early Versus Deferred Antiretroviral Therapy for HIV on Survival," and editorial, "When to Start Antiretroviral Therapy - Ready When You Are?" were published in the New England Journal of Medicine (2009;360(18):1815-1826 and 1897-1899, respectively).