Durability of switched therapy after failure of WHO-recommended antiretroviral therapy regimens in a resource-limited setting.

OBJECTIVE

The study investigated the durability of switched therapy and factors associated with the viral rebound among patients on second-line antiretroviral therapy (ART) in Uganda.

DESIGN

A retrospective dynamic cohort of adults initiated on second-line ART after virological failure to first-line ART.

METHODS

Patients on second-line treatment for at least 6 months between 2007 and 2017 were included. Patients were followed, until they experienced a viral rebound (viral load ≥200 copies/ml). Cumulative probability of viral rebounds and factors associated with viral rebound were determined using Kaplan-Meier methods and Cox proportional hazard models.

RESULTS

One thousand, one hundred and one participants were enrolled of which 64% were women, the median age was 37 years [interquartile range (IQR) 31-43]. The preswitch median CD4 + cell count and viral load were 128 cells/μl (IQR 58-244) and 45 978 copies/ml (IQR 13 827-139 583), respectively. During the 4190.37 person-years, the incidence rate of viral rebound was 83.29 [95% confidence interval (CI) 74.99-92.49] per 1000 person-years. The probability of viral rebound at 5 and 10 years was 0.29 (95% CI 0.26-0.32) and 0.62 (95% CI 0.55-0.69), respectively. The median rebound-free survival was 8.7 years. Young adults (18-24 years) [adjusted hazard ratio (aHR) 2.49, 95% CI 1.32-4.67], preswitch viral load at least 100 000 copies/ml (aHR 1.53, 95% CI 1.22-1.92), and atazanavir/ritonavir (ATV/r)-based second-line (aHR 1.73, 95% CI 1.29-2.32) were associated with an increased risk of viral rebound.

CONCLUSION

Switched therapies are durable for 8 years after failure of recommended regimens. A high preswitch viral load, ATV/r-based regimens, and young adulthood are risk factors for viral rebound, which underscores the need for more durable regimens and differentiated care services.