Adherence to antiretroviral therapy in Africa - Wiley Online Library

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Tropical Medicine and International Health

doi:10.1111/j.1365-3156.2008.02131.x

volume 13 no 9 pp 1096–1097 september 2008

Editorial

Adherence to antiretroviral therapy in Africa: how high is it really? Shabbar Jaffar1, Paula Munderi2 and Heiner Grosskurth1,2 1 Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK 2 Medical Research Council/Uganda Virus Research Institute (MRC/UVRI) Research Unit on AIDS in Uganda, Entebbe, Uganda

keywords adherence, antiretroviral, Africa, survival, RNA viral load More than two million people in Africa are now receiving antiretroviral therapy (ART) compared with just 100,000 in 2003 (WHO 2008), and very high adherence to ART has been reported in a number of different settings. In a metaanalysis, on average, 82% of African patients reported taking 95% or more of their prescribed doses in the last 28 days, whereas only 55% of US patients did (Mills et al. 2006). In the UK, about 70% of patients are thought to be achieving this level of adherence (Brook et al. 2001). At face-value, these findings are very encouraging for the ART roll-out in Africa, but it would be surprising if adherence in Africa was in fact higher than in developed countries. In Africa, access to health care is restricted, monitoring and support of patients is less frequent, fewer antiretrovirals are available and the nature of side-effects and their management are less well understood. Measurement of adherence is subjective and at least in the UK, both self-reports of adherence and physician assessments exaggerate adherence (Gill et al. 2005). We know relatively little about the reliability of adherence measurement in Africa. Differences in the accuracy of measurement may explain the differences in reported rates of adherence between Africa and developed countries. Poor adherence in Africa could threaten the sustainability of ART programmes, and if adherence is indeed a major challenge, it is vitally important that we find out now and target scarce resources accordingly. Many of the studies on adherence in Africa have been conducted in research settings. For example, one of the early reports showing very high adherence comprised subjects who were in clinical trials, who would have received much better care and support than patients in a routine care setting (Orrell et al. 2003). Also, adherence is generally only measured in subjects who attend clinic and are well enough to be interviewed. A recent review suggests that retention of patients in ART programmes in Africa is very low: retention was just 62% by 24 months, with loss to follow-up accounting for 56% of non-retained patients 1096

and death accounting for 40% (Rosen et al. 2007). Death rates are high among subjects lost-to-follow-up (Yu et al. 2007; Dalal et al. 2008); thus, if these findings on retention are true, adherence could have been grossly overestimated through the exclusion of such subjects. Research is needed to identify the reasons why patients do not continue treatment, on the implications of this for ART resistance and on strategies to maximise retention. Plasma RNA viral load should become undetectable within about 4 months in the vast majority of ART naive subjects who adhere adequately (Gazzard 2005) and so could act as an objective marker of adherence. However, because of costs, this is tested in only a few settings in Africa with a good infrastructure. Testing is only possible in subjects who attend clinic and provide blood. Different settings have different monitoring and support of patients and may use different combinations of ART with varying levels of antiviral potency. Thus, comparisons between settings need to be made with caution. Among such selected individuals, plasma RNA