Temporal changes in the epidemiology of transmission of drug-resistant HIV-1 across the world.

A substantial number of studies have been performed across the world to determine transmitted drug resistance. Large variations between different parts of the world can be expected because of differences in availability over time of treatment. Time trend analyses are often not possible because of small numbers of included patients. In this review, we present the available data on the transmission of drug-resistant HIV, with a major emphasis on the time trends of drug resistance prevalences. We identified relevant literature by searching in PubMed through September 2009. Studies were grouped, according to the year of data collection, into the following time periods: < 2001, 2001-2003, > 2003. We selected a total of 215 studies, which included 43,170 patients. The following prevalences of transmission of drug-resistant HIV were found, in rank order: North America (12.9%), Europe (10.9%), Latin America (6.3%), Africa (4.7%), and Asia (4.2%). Changes over time in particular drugs classes were found in all parts of the world. Nucleoside reverse transcriptase inhibitor resistance declined over time in North America (p = 0.03), Europe (p < 0.001), and Latin America (p < 0.001). The decline in nucleoside reverse transcriptase inhibitor resistance reflects the improvement of treatment regimens in resource-rich settings. In contrast the resistance prevalence increased in Asia (p = 0.047) and Africa (p < 0.001). This can be explained by the antiretrovirals becoming more available during recent years in these continents. Nonnucleoside reverse transcriptase inhibitor resistance rose over time in North America (p < 0.001), Europe (p < 0.001), Latin America (p < 0.001), and Asia (p = 0.01). This paper gives a complete overview of the epidemiology of resistance of antiretroviral drugs in drug-naive patients worldwide. The time trends that were observed seem to reflect changes in describing prescriptions over time. Changes include the more wide-spread use of antiretroviral drugs in developing countries and the development of therapies from low-active mono-therapies to highly active antiretroviral regimens in the industrialized countries.