Rates of transmitted HIV drug resistance rising in the U.S.
The increase is driven primarily by resistance to nonnucleoside reverse transcriptase inhibitors.
Accurate epidemiologic surveillance of transmitted HIV drug resistance has important implications for both recommendations of first-line antiretroviral therapy (ART) and community efforts to prevent such resistance. Investigators recently evaluated the changing rates of transmitted HIV drug resistance among 720 patients with acute or chronic infection in the southeastern U.S.
All the study participants presented for HIV care in North Carolina between 1999 and 2010 and had an HIV genotyping test prior to ART initiation. They were classified as acutely infected if they had a negative enzyme-linked immunosorbent assay (ELISA) or Western blot (WB) result either in combination with a positive HIV viral-load test or in the 45 days before a positive ELISA or WB.
The overall prevalence of transmitted HIV drug resistance during the 11-year study period was 9.3%, with 1.5% of patients harboring dual-class resistance. Nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance was the most common (5.7% prevalence), and protease inhibitor resistance was the least common (1.5%). Patients with documented acute infection had a significantly higher prevalence of transmitted drug resistance than those with chronic infection (21% vs. 9%; adjusted prevalence ratio, 1.9).
The prevalence of transmitted drug resistance increased over time for both acutely and chronically infected patients, and this increase was driven primarily by a 20% annual increase in the rate of NNRTI resistance. For the most recent calendar years (2006–2010), the prevalence of transmitted drug resistance was 28% for acutely infected patients and 11% for chronically infected patients. The prevalence of transmitted NNRTI resistance in the same period was 24% for acutely infected patients and 7% for chronically infected patients
Comment: Several aspects of these results are noteworthy. First, the rising rates of transmitted HIV drug resistance reported here are likely generalizable outside the Southeast, given how closely they correspond with preliminary national data from the CDC (Abstract 730, CROI 2012). Second, these results highlight the importance of performing HIV resistance genotyping at the time of diagnosis, regardless of whether ART will be initiated. Finally, this study suggests that current estimates of transmitted drug resistance are likely substantial underestimations, given that acutely infected patients represent only a minority of those included in surveillance efforts.
By Jonathan Z. Li, MD
Dr. Li is an Instructor in Medicine at Brigham and Women's Hospital in Boston. He reports no conflicts of interest.
Published in Journal Watch HIV/AIDS Clinical Care October 15, 2012
Yanik EL et al. Prevalence of transmitted antiretroviral drug resistance differs between acutely and chronically HIV-infected patients. J Acquir Immune Defic Syndr 2012 Oct 1; 61:258.
Source: Journal Watch