More than 400,000 HIV-positive South Africans have begun antiretroviral treatment (ART) since the government launched its programme in 2004. But this impressive-sounding figure still only represents one third of the estimated number of people in need of treatment, and that number is expanding by an additional half a million people every year.

If South Africa is to achieve its ambitious goals for expanding treatment access, as well as the UN Millennium Development Goal of universal access, the current models for delivering treatment will need an overhaul.

This was the finding of a study that compared antiretroviral (ARV) service delivery in three South African provinces: Western Cape, Gauteng and the Free State.

Helen Schneider, a researcher with the Centre for Health Policy at the University of Witwatersrand, noted while presenting the study at the 4th Public Health Association of South Africa Conference in Cape Town on Tuesday that despite the existence of national policies and guidelines for ARV treatment, "implementation is strongly driven by what happens at provincial and district level."

A comparison of 16 facilities providing treatment in the three provinces revealed wide variations in referral systems and staffing levels, but in all three provinces the researchers found a lack of integration of ARV services with other health services. Patients frequently had to go to other facilities for the treatment of TB, or for other opportunistic infections, or for antenatal care.

The study also found that in many districts there were too few doctors and pharmacists providing ARV services, creating service bottlenecks. Systems for monitoring and evaluating patients on ARV treatment were also generally weak, and the use of data to improve services even weaker.

"These models won't be sufficient to achieve universal access," Schneider said. She recommended a shift towards more integrated ARV services, delivered primarily by nurses at primary health care clinics.

The challenge is not only to expand the numbers of people receiving treatment, but to safeguard the quality of treatment, said Dr David Pienaar of the University of Cape Town's School of Public Health and Family Medicine.

"We know there's a need for rapid expansion of ART in South Africa over the next five years," he told conference delegates, "but without excellent adherence there's a risk of individual treatment failure and population-level drug resistance."

Pienaar and his colleagues had interviewed patients at five ARV clinics in two districts of the Western Cape to discover what factors determined good treatment adherence.

They found that a patient's age, gender and education level had much less to do with whether or not they consistently took their ARV drugs than the distance they lived from the facility where they accessed treatment: those living more than 20 minutes away from a treatment site were more likely to report missing doses.

Patients who had a treatment "buddy", a friend or relative who reminded them to take their medication every day, were 66 percent more likely to report excellent adherence, while patients co-infected with TB and HIV were more likely to adhere to both sets of medication if they could access them at one facility.

Overall, the study found good levels of adherence, but Pienaar cautioned that the median length of time patients had been on treatment was only seven months.

South Africa is still in the "activist-led start-up phase" of its treatment rollout, he said. The longer-term outcomes of the programme were less certain, especially considering the study finding that a patient's adherence dropped by two percent for each month they were on treatment. "We need to ensure that clinics are accessible and placed in the areas of greatest need," Pienaar said.

Other recommendations included encouraging patients to be tested earlier and to disclose their HIV status; to establish more community-based adherence support systems, and moving towards greater integration of HIV and TB services.