Emergence of drug resistance
Kelly Safreed-Harmon for Aidsmap (22 September 2010 )
A pilot project using “early warning indicators” (EWIs) to minimize antiretroviral (ART) resistance in Namibia has provided further evidence of the potential value of this strategy in settings where routine viral load monitoring is not feasible.
The World Health Organization (WHO) has encouraged resource-limited countries to integrate EWIs into their monitoring activities. EWIs measure how well ART programs are performing in terms of factors associated with the emergence of drug resistance, such as clinic appointment-keeping and loss to follow-up.
With more than four million people in the developing world now receiving antiretroviral therapy, but few of those people able to access the relatively costly laboratory tests that are a standard component of HIV medical care in wealthy countries, there is ongoing concern that high rates of undetected treatment failure could cause widespread drug resistance.
In Namibia, which has an 18% adult HIV prevalence rate, ART is free of charge at public-sector clinics. Namibia has one of the highest ART coverage rates in sub-Saharan Africa, with treatment being provided to 88% of people for whom treatment is indicated. That figure represents 40,000 public-sector patients and 12,000 private-sector patients.
Public health planners in Namibia implemented the EWI approach using data from a sample of 3,240 patients attending nine public-sector HIV treatment centers. Their analysis, presented as an advance online publication of the Journal of Acquired Immune Deficiency Syndromes, highlighted strengths and weakness of the national ART treatment program. It also called attention to data gaps that hampered program monitoring.
WHO describes the use of EWIs as a key element in the global HIV drug resistance strategy it introduced in 2008.
WHO has selected six core EWIs and two optional EWIs partly on the basis of how feasible it is thought to be for countries to use existing electronic and paper-based records for monitoring.