The authors of a new study say more than one-third of patients in Africa receiving HIV medication discontinue their treatment within two years. As VOA's Jessica Berman reports, the findings could help improve patient retention.

Researchers at Boston University in Massachusetts studied detailed information on HIV-positive adult patients receiving antiviral treatment in 13 sub-Saharan African countries over a seven-year period.

The investigators found that two years after beginning treatment, only 61 percent of people on average were still taking anti-HIV drugs.

Christopher Gill is an infectious diseases specialist and co-author of the study, appearing in the online journal PLoS Medicine.

Gill says the study was designed to assess the effectiveness of HIV drug delivery programs in the developing countries, and he is concerned about the finding that up to one-third of patients drops out of drug treatment.

"It does kind of make you worry a little bit because it means that for whatever reason these programs are unable to track patients who have started therapy," he said. "You know perhaps that's because patients are migrating a lot but it could also be that patients are being lost to the roles either because they have died unobserved and we don't know it has happened or because they have given up treatments and they are not sort of found and brought back into clinics and what have you."

Gill says public health officials have proved that it possible to bring anti-HIV therapy to poor countries on a large scale.

Gill says the new challenge is to find ways to make sure people who are taking the AIDS drugs continue to do so.

"What can we do to reduce the attrition rate from forty percent to ten percent. How do we make it better still? So, I think of this as a call to action in terms of how to improve the situation further," he said.

The authors say one way to improve retention might be to find out exactly why people fall out of treatment programs and address the various issues, such as the cost of treatment or transportation to clinics.

Also, they say HIV treatment clinics with higher retention rates could serve as models to improve retention in other programs.