Characterization of Genotypic Mutations and Antiretroviral Resistance among Viremic HIV-Infected Patients in a High HIV Prevalence Area: Treatment Challenge and Transmission Risk

There have been few reports evaluating the prevalence of genotypic mutations and antiretroviral resistance among chronic HIV-infected Veterans within the United States. This retrospective cross-sectional study characterizes the rates and changes in HIV genotypic mutations and antiretroviral resistance among viremic patients from 2001 to 2006 at the VA Medical Center located in Washington, DC. The District of Columbia is the metropolitan area with the highest HIV prevalence within the United States. De-identified, linked HIV RNA, genotypic reverse transcriptase (RT) and protease (Pr) mutations and antiretroviral resistance results were assessed for changes during the 6-year period. Aggregated clinic and antiretroviral utilization, and HIV acquisition risk data were evaluated for patients in care during this time. Among 990 viremic samples, the rate of any detected RT or Pr mutation fell from 100% in 2001 to 95% in 2006. This was primarily attributable to the 15% - 20% decrease seen for RT gene mutations against nucleoside/nucleotide class and non-nucleoside class during this period. Resistance to didanosine, stavudine, zidovudine, nevirapine and efavirenz decreased, and tenofovir resistance increased. Despite stable rates of Pr gene mutations, atazanavir resistance increased by 22% from 2003 to 2006. Some but not all changes in genotypic mutations and resistance patterns reflected our patients’ antiretroviral drug utilization. As sexual contacts (77%) and injection drug use (22%) were the leading acquisition risks disclosed by our HIV-infected patients, the high prevalence and changing patterns of HIV genotypic mutations and drug resistance among these patients have had pivotal impacts not only on HIV treatment but potential transmission into our community.