Adherence in Cape Town poor just as good as US and Europe

In South Africa, the presumption that indigent patients might not stick to pill-taking schedules has served as an excuse to delay the extension of antiretroviral treatment to the HIV-infected population. However, according to a study published in the June 12^th edition of AIDS by Dr. Catherine Orrell et al., “adherence is not a barrier to successful antiretroviral therapy in South Africa.”

Dr Orrell and colleagues from Somerset Hospital, a government hospital in Cape Town, found a high rate of adherence in a cohort of their HIV-positive patients initiating treatment, even among those living in extreme poverty. In fact, patients in the study took 93.5% of their prescribed medication, which is as good, if not better, than reported adherence in most of the clinical and observational studies in Europe and in North America. Contrary to the conventional wisdom “socio-economic status had no impact on adherence in our cohort,” said Dr Orrell.

The team from Somerset prospectively monitored adherence and evaluated factors predicting poor adherence and virologic failure in 289 patients who enrolled in six antiretroviral trials at between January 1996 and May 2001. Adherence was measured over 48 weeks by pill count. At each visit, patients were given more medication than required and instructed to return all medication bottles and unused pills at the next study visit — but patients were not told that the returned pills were to be counted.

Many of the study participants lived in extreme poverty. Forty two percent of the cohort came from households earning less than US$1500 per annum, while a further 20% earned less than US $5500 per year. However in a multivariate analysis, the only factors related to poorer adherence were youth, three-times daily dosing, and home language. Patients whose home language differed from that spoken by most of the hospital staff (English) were less adherent, possibly because instructions on dosing were given in that language. The majority of the cohort spoke Xhosa, the local African language (48%), or Afrikaans (28%), but this was unrelated to socio-economic status.

Overall, sixty three percent of the patients maintained adherence of ³ 90% to the prescribed tablets. Adherence was significantly associated with the reduction in viral load at 48 weeks. Of those that reached 48 weeks of therapy (n = 242), 66.1% had a viral load of

The rate of adherence and viral suppression was similar to or better than that reported in developed countries where patients on similar regimens take about 70% of their HIV antiretroviral medications and the rate of viral load suppression is around 50% - 60% after 48 weeks. The high proportion of adherence in the Somerset study is particularly noteworthy because there was no dedicated adherence counselling service, structured adherence support or formal adherence intervention as part of treatment. The patients only had access to the trial site for one to two hours every two or three months and there were no off-site visits by health care staff to encourage adherence.

The Somerset team admits that there may be some selection bias in their study — patients had to be highly motivated to get into a trial, and — given the scarcity of anti-HIV treatment in South Africa — doctors may have more motivated to enroll patients they felt would closely adhere to treatment. Dr Orrell partly attributes the high rate of adherence to the fact that there is such limited access to antiretroviral therapy in South Africa. “There’s an element of desperation for people who know that they are very fortunate to be in a program offering free antiretroviral treatment. Also a number of these patients have been unwell, and have then responded to treatment. They have seen where they would be going without treatment — and I think that contributes to their adherence to therapy.”

These findings dispute the essentially unsubstantiated view that sub-Saharan Africans are unable to adhere to antiretroviral treatment. In the paper, Orrell cited a statement once made by Andrew Natsios of USAID: “Ask Africans to take their drugs at a certain time of day, and they do not know what you are talking about” (Attaran A, Washington Post 2001; June 15).

But the data tell a different story: “Our results which indicate that poor patients in sub-Saharan Africa can achieve high rates of adherence and viral suppression even without direct observed therapy or other formal adherence interventions.”

But are the results from a semi-urban setting pertinent to rural Africa? “To me, if people can access services in their home language, they should do just as well,” said Dr Orrell. “The hold-up to implementing effective treatment in Africa, is the infrastructure and resources, it is not the people.

“I agree” says Dr Douglas Wilson who is working with indigent semi-urban and rural patients living around Pietermaritzburg in KwaZulu-Natal. "These very encouraging results shows that African patients living in difficult circumstances can achieve good adherence and viral suppression. The next challenge is to demonstrate similar outcomes in community-based antiretroviral projects.”