Pretreatment HIV-1 drug resistance to first-line drugs: results from a baseline assessment of a large cohort initiating ART in Vietnam, 2009-10.

OBJECTIVES: The objective of this study was to determine the prevalence and correlates of pretreatment drug resistance (PDR) to first-line antiretroviral drugs among people initiating therapy for HIV in Vietnam. METHODS: Blood was collected during November 2009 to October 2010 from people consecutively initiating ART in four purposively selected public outpatient clinics in three Vietnamese cities. At each study site, recruitment lasted for 6-10 months until the target sample size (range 120-130 individuals) had been reached. The viral load was measured in 501 samples; 490 samples (viral load ≥1000 copies/mL) were genotyped using a nucleotide population-based sequencing assay. Self-reported demographic and clinical data were elicited through interviews. We classified drug-resistance-associated mutations (DRMs) according to the 2009 WHO surveillance list. RESULTS: DRMs were identified in 17/490 participants (3.5%; 95% CI 2.2%-5.5%). The prevalence of DRMs was 1.6% (8/490) against NRTIs, 1.6% (8/490) against NNRTIs and 0.8% (4/490) against PIs; three (0.6%) participants were resistant to both NRTIs and NNRTIs. The overall prevalence of PDR to first-line drugs was low [2.7% (13/490); 95% CI 1.6%-4.4%]. The prevalence of PDR to first-line drugs was greater among 198 HIV-infected participants who injected drugs than among 286 participants who reported risks for sexually acquired HIV (4.0% versus 1.4%, P = 0.079). Multivariable logistic regression analysis suggested that PDR to first-line drugs was significantly higher among people who injected drugs (OR = 3.94; 95% CI 1.13-13.68). CONCLUSIONS: With low PDR, first-line ART may be effective in Vietnam and pretreatment genotyping may be unnecessary. Continuing strategies for the prevention and surveillance of antiretroviral resistance are important for maintaining a low prevalence of antiretroviral resistance in Vietnam. The association between resistance and injection drug use warrants further research.

Outcomes of antiretroviral therapy in Vietnam: results from a national evaluation.

OBJECTIVES: Vietnam has significantly scaled up its national antiretroviral therapy (ART) program since 2005. With the aim of improving Vietnam's national ART program, we conducted an outcome evaluation of the first five years of the program in this concentrated HIV epidemic where the majority of persons enrolled in HIV care and treatment services are people who inject drugs (PWID). The results of this evaluation may have relevance for other national ART programs with significant PWID populations. DESIGN: Retrospective cohort analysis of patients at 30 clinics randomly selected with probability proportional to size among 120 clinics with at least 50 patients on ART. METHODS: Charts of patients whose ART initiation was at least 6 months prior to the study date were abstracted. Depending on clinic size, either all charts or a random sample of 300 charts were selected. Analyses were limited to treatment-naïve patients. Multiple imputations were used for missing data. RESULTS: Of 7,587 patient charts sampled, 6,875 were those of treatment-naïve patients (74.4% male, 95% confidence interval [CI]: 72.4-76.5, median age 30, interquartile range [IQR]: 26-34, 62.0% reported a history of intravenous drug use, CI: 58.6-65.3). Median baseline CD4 cell count was 78 cells/mm(3) (IQR: 30-162) and 30.4% (CI: 25.8-35.1) of patients were at WHO stage IV. The majority of patients started d4T/3TC/NVP (74.3%) or d4T/3TC/EFV (18.6%). Retention rates after 6, 12, 24, and 36 months were 88.4% (CI: 86.8-89.9), 84.0% (CI: 81.8-86.0), 78.8% (CI: 75.7-81.6), and 74.6% (CI: 69.6-79.0). Median CD4 cell count gains after 6, 12, 24, and 36 months were 94 (IQR: 45-153), 142 (IQR: 78-217), 213 (IQR: 120-329), and 254 (IQR: 135-391) cells/mm(3). Patients who were PWID showed significantly poorer retention. CONCLUSIONS: The study showed good retention and immunological response to ART among a predominantly PWID group of patients despite advanced HIV infections at baseline.