Comparing Type and Prevalence of HIV Drug Resistance in Treatment Experienced and naïve HIV-infected Adults in Uganda and Switzerland

Background & Rational Uganda and Switzerland are two examples of regions in the world that have experienced the era of antiretroviral treatment (ART) in substantially different ways. While European patients had access to ART from the beginning of drug development, ART was made accessible to patients from sub-Saharan Africa many years later. HIV-infected patients in resource-limited settings were not subjected to the early days of treatment, were mono therapy was tried or combinations of drugs that are off the market nowadays. Furthermore, in contrast to European patients, patients from resource-limited settings were constantly confronted with economic constraints leading to stock-outs for instance. Cultural aspects, such as stigma and fear of disclosure, differ as well, and are well known to influence individual adherence and treatment outcome substantially.

Today similar first-line treatment choices are made by Ugandan and Swiss physicians, but monitoring strategies still differ. As in other countries of sub-Saharan Africa, treatment of HIV-infected patients is monitored immunologically and clinically, while viral load measurement is reserved for selected patients. In accordance with WHO recommendations treatment failure is therefore determined clinically (new or recurrent WHO stage III or IV condition) and/or by the decline of a patient's CD4 cell count to or below baseline, which usually occurs late during insufficient treatment. Viral rebound and emergence of resistance may thereby arise. Moreover, misclassification of treatment failure (e.g. patients with immunological failure in the absence of virological failure or complete non-adherence to treatment) may result in premature switching to more costly second-line treatment options.

The currently available information on transmitted drug resistance (TDR) in Ugandan adults shows lower rates compared to patients from European countries, including Switzerland. Yet, available studies were conducted with small patient numbers. Newer data from Uganda, especially under new WHO treatment recommendations, is not available yet.

To the best of investigators' knowledge, so far no study has directly compared HIV drug resistance data from a resource-limited country to a resource-rich country. Little is known about the effects of historically, culturally and economically different ART experiences on resistance. With the 2013 WHO guidelines, ART roll-out will be enhanced globally and the continued success of these large-scale treatment programs will depend on the prevention of further emergence of drug resistance.

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