HIV-1 drug resistance and associated factors among adults failing first-line highly active antiretroviral therapy in Ho Chi Minh City, Vietnam.

Background & Objectives: Little is known about HIV-1 drug resistance (HIVDR) in people failing first-line highly active antiretroviral therapy (HAART) in Vietnam. The aim of this study was to investigate the frequency of HIV-1 drug resistance mutations (DRMs) and determine correlates of acquiring genotypic HIVDR among Vietnamese adults (age >= 18) who met the immunological or clinical criteria of first-line HAART failure according to the guidelines of the World Health Organization (WHO). Methods: A total of 138 individuals participated in a descriptive study in Ho Chi Minh City between 2006 and 2009. Blood samples were collected for performing HIV-1 viral load (VL) and genotyping for specimens with VL >= 1,000 copies/mL. Stanford algorithm was used to interpret DRMs and multivariate analyses were performed to investigate predictors of HIVDR acquisition. Results: Of the study population, most participants failed either stavudine/lamivudine/nevirapine or stavudine/lamivudine/efavirenz (1.16 individuals). Up to 51 people obtained a VL <1,000 copies/mL. Among 87 participating individuals with VL >= 1,000 copies/mL, 11 people still harbored a wild-type strain, while 76 participants harbored a HIV-1 drug-resistant strain (2 of which were against protease inhibitors); common DRMs were M184I/V (74%), Y181I/C/V (39%), G190A/S (32%), T215Y/F (32%), and K103N (31%). The proportions of K65R, Q151M, and T69 insertion were 13%, 11%, and 5%, respectively. Being antiretroviral-exposed before initiating first-line HAART in a public and free-of-charge outpatient clinic, having nonadherence to first-line HAART, per 12-month increase of duration on first-line HAART, and having clinical failure criteria were significantly associated with a genotypic HIVDR acquisition. Conclusions: In the absence of VL for the population with WHO immunological/clinical treatment failure criteria, a large proportion of people still achieved a VL <1,000 copies/mL, while a high prevalence of HIVDR was observed in those with VL >= 1,000 copies/mL. Thus, VL monitoring should be implemented now for the HAART-treated population in Vietnam.