Background: Emerging HIV drug resistance (HIVDR) poses a growing threat to the long-term success and durability of highly active antiretroviral therapy (HAART).
Objective: To understand the development of HIVDR and estimate the proportion of potential HIVDR and its associated risk factors among the patients on HAART for one year.
Methods: Antiretroviral-naive patients ≥18 years old were invited to participate in this one-year prospective study from seven clinics in Yunnan, Guangxi, and Xinjiang provinces. A questionnaire and blood draw were collected at baseline and 12 month follow-up. The protocol used was modified slightly from the WHO Protocol for Surveys of HIV Drug Resistance Emerging During Treatment and Related Program Factors in Sentinel ART Sites in Resource-limited Settings.
Results: 435 patients were included in the study, of whom 351 (80.7%) were retained at 12 months. The median baseline CD4 cell count of 351 patients retained at 12 months was 132 cells/mm3, which increased to 305 cells/mm3 at 12 months (P < 0.0001), with those from Yunnan and Guangxi receiving d4T/3TC/NVP and Xinjiang receiving AZT/3TC/NVP. Of the total 435 subjects, 417 met the WHO guideline for classification of outcomes based on endpoints, of whom 310 (75.3%) had a viral load < 1000 copies/ml at 12 months (HIVDR prevention), 17 (4.1%) had a viral load ≥ 1000 copies/ml at 12 months and at least one resistance mutation identified, and 90 (21.6%) were classified as potential HIVDR, including 24 with viral loads≥1000 copies/ml at 12 months but no drug resistance mutations, 42 who were lost to followup, and 24 who had discontinued ART by 12 months. In a logistic regression analysis, patients who self-reported missing doses in the previous month were 8.0 fold (95% CI 3.1-20.9) more likely to develop virologic failure than those who did not. and those from Xinjiang were 12.6 fold (95% CI 5.3-29.8) more likely to fail compared to those from Yunnan and Guangxi. Patients with baseline viral load > 100000 were 3.2 fold (95% CI 1.4-6.9) more likely to fail than those whose baseline viral load≤100000. Why Xinjiang was associated with virologic failure was not clear but may be related to the demographics of the participants from Xinjiang, being significantly more IDUs, poorer, and less adherent than those from Yunnan and Guangxi.
Conclusions: Although successful virologic outcomes were seen in the vast majority (75.3%) of those treated at one year, virologic failure continues to be a problem particularly among those less adherent and from Xinjiang. Additional data are needed to understand the generalizability of these results, particularly those related to Xinjiang. For IDUs, enhancing adherence to HAART and considering the treatment of drug addiction as an integral part of the treatment for HIV infection should be considered. As Chinas National Free Antiretroviral Treatment Program continues to mature and improve, ramping up treatment in these settings may be important considerations to the long-term success of the program.