Rates of emergence of HIV drug resistance in resource-limited settings: a systematic review.
BACKGROUND
The increasing availability of antiretroviral therapy (ART) has improved survival and quality of life for many infected with HIV, but can also engender drug resistance. This review summarizes the available information on drug resistance in adults in resource-limited settings.


METHODS
The online databases PubMed and Google Scholar, pertinent conference abstracts and references from relevant articles were searched for publications available before November 2011. Data collected after ART rollout were reviewed.


RESULTS
A total of 7 studies fulfilled the criteria for the analysis of acquired drug resistance and 22 fulfilled the criteria for the analysis of transmitted drug resistance (TDR). Acquired resistance was detected in 7.2% of patients on ART for 6-11 months, 11.1% at 12-23 months, 15.0% at 24-35 months, and 20.7% at ≥ 36 months. Multi-class drug resistance increased steadily with time on ART. The overall rate of TDR in all resource-limited countries studied was 6.6% (469/7,063). Patients in countries in which ART had been available for ≥ 5 years were 1.7 × more likely to have TDR than those living in a country where ART had been available for <5 years (P<0.001). The reported prevalence of TDR was 5.7% (233/4,069) in Africa, 7.6% (160/2,094) in Asia and 8.4% (76/900) in Brazil.


CONCLUSIONS
The emergence of drug resistance following access to ART in resource-limited settings resembles what was seen in resource-rich countries and highlights the need for virological monitoring for drug failure, drug resistance testing and alternative drug regimens that have proven beneficial in these resource-rich settings.
University of California, San Diego, La Jolla, CA, USA.
Kathryn M
KM
Stadeli
Douglas D
DD
Richman
D000328:Adult; D019380:Anti-HIV Agents / Q000494:pharmacology* / Q000627:therapeutic use; D003906:Developing Countries / Q000706:statistics & numerical data*; D024882:Drug Resistance, Viral; D015658:HIV Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000401:mortality; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D015995:Prevalence
D019380:Anti-HIV Agents