Adherence is not a barrier to successful antiretroviral therapy in South Africa

1 July 2003. Related: Treatment access.

Polly Clayden, HIV i-Base

It is a widely held assumption that people in resource poor settings will be unable to be adherent to antiretroviral therapy, providing yet another barrier to their access to medicines essential to their care. A paper published in AIDS reports findings from an investigation designed to measure adherence in a cohort of semi-urban South Africans living in extreme poverty.

A total of 289 drug naïve patients were enrolled into this multi centre study recruited from the Cape Town AIDS Cohort receiving ART through phase III trials between January 1996 and May 2001.

All participants were ARV naïve and provided written consent to participate in the trials. Single group education sessions (generally in English) were conducted prior to the consenting process and study entry. No dedicated adherence counselling services, structured treatment support or formal adherence interventions were provided as part of the protocol. There were no off site visits by health care staff.

Patients in two studies in 1996 received dual therapy with an additional concurrent placebo controlled and double blinded drug (placebo vs NNRTI). In four other studies patients received triple therapy. PI containing regimens were used by 120 (41.5%) patients, NNRTI containing by 94 (32.5%), 30 (10.4%) took triple nucleoside regimens and 45 (15.6%) who initiated therapy in 1996 received dual nucleoside therapy. Regimens of 10 tablets or more per day were used by 55% of the cohort and 41% of regimens had some dietary restrictions.

Adherence to ART was determined over 48 weeks by counting tablet returns. Clinic visits were booked in multiples of 28 days and tablets usually dispensed in multiples of 30. Patients were asked to return all medication bottles and unused pills at each visit.

Logistic regression models including age, WHO clinical stage, home language, socio-economic status, baseline CD4 and viral load, complexity and type of regimen were recorded to determine predictors of incomplete adherence and virologic failure at 48 weeks.

The mean age of the cohort at initiation of therapy was 33.4 years and 43% of participants were women. A large proportion of the cohort came from poor socio-economic conditions (defined as approximately US$1,500 per annum per household) and only 20% spoke English as their home language. The majority spoke Xhosa, the local African language (48%) or Afrikaans (28%).

The median adherence of the cohort was 93.5% (mean 87.2%). Three times daily dosing [risk ratio (RR), 3.07; 95% confidence interval (CI), 1.40–6.74], speaking English (RR, 0.41; 95% CI, 0.21–0.80) and age (RR, 0.97; 95% CI, 0.94–0.99) were independent predictors of incomplete adherence. Socio-economic status, sex and HIV stage did not predict adherence.

Independent predictors of virologic failure included baseline viral load (RR, 2.57; 95% CI, 1.57–4.22) and three times daily dosing (RR, 2.64; 95% CI, 1.23–5.66), incomplete adherence (RR, 1.92; 95% CI, 1.10–3.57), younger age (RR, 0.96; 95% CI, 0.92–0.99) and dual nucleoside therapy (RR, 2.69; 95% CI, 1.17–6.15).

The investigators also reported that 70.9% of patients on triple therapy maintained a viral load of <400 copies at one year. These adherence and suppression results match or surpass those reported in most observational or clinical trial cohorts in developed countries, where adherence measures indicate that patients take 70% of their antiretroviral medicines and the rate of viral load suppression is 50%.

They also noted that speaking the same language as site staff and simplified dosing regimens were beneficial to good adherence. But, most importantly, they concluded, “…Low socioeconomic status was not a barrier to success. Individuals with HIV disease who could potentially benefit from ART should not be denied access based on otherwise unsubstantiated expectations of poor adherence.”

Ref: Orrell C, Bangsberga D, Badri M et al. Adherence is not a barrier to successful antiretroviral therapy in South Africa AIDS 2003, 17:1369–1375

Comment

Expectation of poor adherence is a major concern in any discussions around scaling up therapy and this study cites the oft quoted UNAIDS spokesman’s statement “Ask Africans to take their drugs at a certain time of day and they don’t know what you’re talking about” which seems to sum up these widely held assumptions.

Yet in contrast to current expectations of non adherence, as with a previous report from Senegal, this group demonstrates that high levels of adherence required to implement successful therapy can be achieved even in the absence of formal adherence interventions.

[Laurent C, Diakhate N, gueye NFN et al. The Sengalese government’s highly active antiretroviral therapy initiative:18 months follow up AIDS 2002 16:1363-1370]