No Increase in HIV Drug Resistance Mutations among Injecting Drug Users on Methadone Maintenance Therapy: A Prospective Cohort Study

Background: Whether HIV-positive injecting drug users (IDUs) are at higher risk of developing drug resistance mutations (DRMs) after methadone maintenance therapy (MMT) than any other HIV-positive population is unclear. Objective: To compare the incidence of new DRMs in two population groups: antiretroviraltreatment (ART) HIV-positive IDUs and non-drug users. Methods: A prospective cohort of ART HIV-positive patients including IDUs who received MMT (MMT group) and non-drug users (N-MMT group) was established from April 2016 to December 2017 in Guangxi, China. Results: Of the 80 participants, 43 were in the MMT group and 37 were in the N-MMT group. Compared with the N-MMT group, the HRs of PIs, NRTIs and NNRTIs for new DRMs in the MMT group was 1.55 (95%CI: 0.28-8.64; P = 0.616), 1.51 (95%CI: 0.44-5.20; P = 0.512) and 0.45 (95%CI: 0.15-1.35; P = 0.155), respectively. There was no dose-response relationship between MMT and new DRMs for PIs, NRTIs and NNRTIs (P > 0.05). The new DRM incidence for NRTIs (138.23 per 104 person-months) was higher than for PIs (94.16 per 104 person-months) and NNRTIs (95.41per 104 person-months) in the MMT group, while the new DRM incidence for NNRTIs (208.24 per 104 person-months) was higher than for PIs (44.13 per 104 person-months) and NRTIs (91.78 per 104 person-months) in the N-MMT group. Conclusion: Among ART HIV-positive patients, there is no significant difference in the incidence of new DRMs between IDUs receiving MMT and non-drug users. MMT has little impact on the development of DRMs among IDUs.