WASHINGTON — Treating HIV earlier can increase a patient’s survival chances, a new study of more than 8,000 HIV patients shows. The findings suggest doctors should rethink the standard practice of HIV treatment, a team reports at a meeting of microbiologists and infectious disease researchers.
HIV depletes key immune cells called CD4 T cells. A patient’s T cell count, the concentration of CD4 cells still in circulation, is used to gauge how far the virus that causes AIDS has progressed and to determine when to treat a patient with the frontline drug cocktail for HIV. The standard benchmark for initiating this treatment has been a T cell count of 200 cells per cubic millimeter of blood.
A new study presented by physician and HIV/AIDS specialist Mari Kitahata of the University of Washington in Seattle suggests that the cut-off point should be placed much sooner, at only 500. This benchmark, presented October 26 in Washington, D.C., during the combined meeting of the Infectious Diseases Society of America and the Interscience Conference on Antimicrobial Agents and Chemotherapy, goes even farther than a recommendation in the Aug. 6 Journal of the American Medical Association to start intensive treatment when the T cell count drops to only 350.
Before newer HIV drugs were on the market, doctors often delayed treatment. This was not only because of cost, but also because of the serious side effects from the drugs available at the time and the fear that patients’ failure to stick to the large and onerous daily drug regimen would create drug-resistant HIV, says physician Daniel Kuritzkes of Brigham and Women’s Hospital in Boston. In recent years, though, newer drugs have become available that require fewer daily doses and have less harmful side effects — leading many doctors to reconsider the threshold for beginning treatment.
Kitahata and her colleagues analyzed data from 22 studies of people from Canada and the United States who started the cocktail of HIV therapies between 1996 and 2006 — surveying more than 8,000 HIV patients. By tracking people from entry into the study until either the patients died or the study they were in ended, the researchers could assess whether beginning treatment earlier improved patients’ survival.
The study compared 5,901 patients who followed more standard treatment guidelines and did not begin treatment until CD4 counts were below 350, to 2,473 patients who began treatment when their CD4 counts were between 351 and 500. The data showed that patients who delayed treatment until their T cell count was below 350 faced a 70 percent higher risk of death than patients who started treatment earlier.
This new study provides the largest source of data for comparing different starting times of HIV treatment.
For reasons including lack of access to medical care, many patients who have CD4 counts that are low may not receive treatment, according to Kitahata. “That does not reflect our willingness to treat people,” she says.
Across North America the average patient starts treatment for HIV with a CD4 count of 300, “which means fully half of people [starting treatment] are below that,” says Richard Moore, of Johns Hopkins University in Baltimore, and the principal investigator on the large-scale study.
Kuritzkes says changing the starting point of treatment could save several hundred thousand lives in the United States. “What I think is likely to happen is that as we push the threshold for starting therapy sooner and sooner we’ll get better at identifying high-risk cases … to fine-tune who gets treated earliest and who can wait a little longer,” he says.