First-Line Antiretroviral Regimen Failure and Determinants in an Urban HIV Clinic at Phramongkutklao Hospital, Bangkok, Thailand: 20 Years Experience

PURPOSE: HIV treatment involves antiretroviral therapy (ART) endeavoring to suppress viral load to an undetectable level. Virologic failure occurs when ART fails to suppress and sustain an individual’s viral load to less than 200 copies/mL after 6 months of therapy. In Thailand, the data among first-line antiretroviral regimen failure and determinants remains limited, especially in urban HIV clinics. We aimed to demonstrate factors of first-line antiretroviral regimen failures in an urban HIV/AIDS clinic at Phramongkutklao Hospital. PATIENTS AND METHODS: A nested case control 1:4 study was conducted. Data were collected from the electronic patient database among naïve people living with HIV/AIDS (PLWHA), aged ≥18 years and receiving ART continuously for at least 2 years at Phramongkutklao Hospital from 1 January 2000 to 31 December 2019. Multiple logistic regression was used to identify the determinants of virologic failure. Adjusted HRs (AHRs) with 95% CIs were used to declare statistical significance. RESULTS: Of 200 PLWHA included in the study, 40 participants experienced HIV virologic failure. The median time after starting ART to virologic failure was 24 months (IQR 7–96.0). Univariate and multivariate analysis showed significant factors affecting first-line antiretroviral regimen failure included being female (37.5 vs 26.88%, adjusted odds ratio 5.08 [1.05–24.6, p-value 0.043], age ≤40 yr. (62.5 vs 49.6%, adjusted odds ratio 4.59 [1.47–14.37], p-value 0.009), CD4+count ≤200 cell/µL (77.5 vs 52.5%, adjusted odds ratio 4.83 [1.28–18.9], p value 0.02), tuberculosis (42.5 vs 7.5%, adjusted odds ratio 8.66 [2.37–31.56], p value <0.001) and initiation of ART at CD4+ count <350 cell/µL (72.5 vs 48.13%, adjusted odds ratio 31.36 [6.51–151.22], p value <0.001). Estimated prevalence of virologic failure in Phramongkutklao Hospital was 5.34%. CONCLUSION: Our study revealed factors favoring virologic failure included being female, younger age, CD4+ count <200 cells/µL, tuberculosis and initiation of ART at CD4+ count <350 cell/µL. Multidisciplinary HIV comprehensive care teams should encourage patient adherence and support patients along HIV continuum of care to prevent virologic failure and drug resistance, especially among patients initiating ART at low CD4+ count and tuberculosis co-infection.