The results of increasing HIV drug resistance in patients who are starting Antiretroviral has been linked to increased management failure rates due to treatment interruptions, weak drug supply chains and drug stock-outs, writes DR KIZITO LUBANO

The widespread use of antiretroviral  (ART) drugs and scale up to over one million individuals in Eastern Africa infected with HIV over the last decade has led to tremendous improvements in survival and quality of life.

An inevitable consequence of the widespread availability of ART is treatment failure that selects strains of drug-resistant virus. A subset of individuals who acquire drug-resistant HIV will transmit their drug-resistant virus to others. This scenario, which is well documented in Europe and North America, has been repeated in resource-limited settings.

A recent publication suggests a significant increase in prevalence of drug resistance over time since antiretroviral rollout.

In East Africa, resistance increased at almost 30 per cent yearly, representing the highest increase as compared to other regions. Southern Africa, for instance, was 14 per cent per year, and no increase over time was noted in West and Central Africa as well as in Latin America.

The consequences of increasing HIV drug resistance in patients who are starting ART are substantial and include increased treatment failure rates with greater morbidity and mortality, increased need for more expensive second-line regimens, and costs associated with further transmission of more highly resistant and potentially untreatable viruses.

Among the current first-line drugs, there is an estimated 36 per cent increase in prevalence of resistance mutations per year in East Africa, and 23 per cent in southern Africa every year.  Resistance was noted in recently infected adults as well, indicating transmission of resistant virus.

The contributing factors

Experts in a medical journal, Lancet, say they have assessed data from more than 2000 clinics in 50 countries worldwide between 2004 and 2009 by means of World Health Organisation-defined early warning indicators for drug resistance.

This study documented stock-outs of antiretroviral drugs in about 40 per cent of monitored sites in sub-Saharan Africa. This problem could be addressed through improved supply management systems that would ensure uninterrupted availability of ART.

In the survey, 40 per cent of ART programmes in sub-Saharan Africa were reported to have more than 20 per cent loss to follow-up, indicating that problems with retention of patients are further barriers to successful, sustained viral suppression at the population level.

This optimisation would involve the establishment of robust supply chains to prevent drug stock-outs and treatment interruptions, scale-up of routine viral load monitoring to detect early failures, expanded access to alternative drug regimens, and the development of meaningful and sustainable strategies to overcome structural barriers to adherence and routine defaulter tracing to maximise retention.

Treatment interruption accounts for treatment failure and several recognised causes could be addressed.  Weak drug supply chains and drug stock-outs jeopardise the treatment of even highly adherent patients. Patients lost to follow-up, in part attributable to poor access to clinics, contributes to failure.

Limited resources also constrain approaches to reduce the risk of acquired and transmitted drug resistance. The cost and restricted availability of second-line regimens in resource-limited settings diminish the ability to manage both acquired and transmitted drug resistance.

Now, more than ever, investment and political will are urgently needed to sustain and expand global HIV drug resistance surveillance efforts. Such investments are essential to maximise the effectiveness of treatment scale-up.

Although still within expected levels, further increases in the prevalence of HIV drug resistance might jeopardize the global HIV response and curb a decade-long trend of decreasing HIV-related morbidity and mortality in low-income and middle-income countries.

However, no changes in antiretroviral treatment guidelines are warranted at the moment.