Objective  To examine the incidence rate and influencing factors of virologic failure (VF) among human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) patients after antiretroviral therapy (ART) in Chengdu city from 2008 to 2018.

  Methods  The data on all HIV/AIDS patients receiving initial ART from 2008 through 2017 were extracted from the National Integrated HIV/AIDS Prevention and Control Information System and the patients were retrospectively followed-up till December 31, 2018. Cox proportional hazard model was used to explore factors associated with VF after ART treatment.

  Results  Among 19 945 HIV/AIDS patients included in the study, 2 500 individuals experienced VF, with an incidence rate of 4.45 per 100 person-years. Multivariate Cox proportional hazard analysis demonstrated that the level of pre-ART CD₄⁺ T cell count (CD₄) were significantly associated with VF. Compared to the patients with the baseline CD₄ count of ≥ 500 cells/μL, the adjusted hazard ratio (aHR) of VF was 11.908 (95% confidence interval 95% CI: 9.838 – 14.412), 2.824 (95% CI: 2.484 – 3.212), and 1.586 (95% CI: 1.420 – 1.771) for the patients with the baseline CD₄ count of 0 – 49, 50 – 199, and 200 – 349 cells /μL, respectively (P < 0.01 for all); in contrast to the patients with delayed ART (the time from the diagnosis to the initial treatment: ≥ 366 days), the aHR of VF was 0.829 (95% CI: 0.734 – 0.935) and 0.840 (95% CI: 0.755 – 0.934) for the patients with immediate ART (the time from the diagnosis to the initial treatment: ≤ 30 days and 31 – 365 days ); the analysis also revealed that in comparison with the female patients, the male patients were more likely to have VF (aHR = 1.216, 95% CI: 1.090 – 1.356); the patients with initial ART regimen of zidovudine + lamivudine + efavirenz/nevirapine (AZT + 3TC + EFV/NVP) were more likely to have VF (aHR = 1.272, 95% CI: 1.153 – 1.402) compared to the patients with the initial ART regimen of tenofovir (TDF) + 3TC + EFV/NVP.

  Conclusion  Lower baseline CD₄, delayed initial ART after HIV diagnosis, male gender and AZT + 3TC + EFV/NVP regimen are significantly associated with increased risk of VF among HIV/AIDS patients in Chengdu city.