Time to Viral Re-suppression and Its Predictors among Adults on Second-Line Antiretroviral Therapy in South Wollo Zone Public Hospitals: Stratified Cox Model.

Background: Even though there are many patients on second-line antiretroviral therapy (ART) in Ethiopia, there is a paucity of evidence on the rate of viral resuppression and its predictors. Therefore, this study aimed to determine a time to viral resuppression and identify predictors among adults on second-line ART in South Wollo public hospitals, northeast Ethiopia. Methods: A retrospective-cohort study design was employed using patients enrolled in second-line ART from August 28, 2016 to April 10, 2021. Data were collected using a structured data-extraction checklist with a sample size of 364 second-line ART patients from February 16 to March 30, 2021. EpiData 4.6 was used for data entry and Stata 14.2 was used for analysis. The Kaplan-Meier method was used for estimating time to viral resuppression. The Shönfield test was used to check the proportional-hazard assumption, and the "no interaction" stratified Cox assumption was checked using the likelihood-ratio test. A stratified Cox model was applied to identify predictors of viral resuppression. Results: Median time to viral re-suppression in patients on a second-line regimen was 10 (IQR 7-12) months. BeingFemale (AHR 1.31, 95% CI 1.01-1.69), low viral load count at switch (AHR 1.98, 95% CI 1.26-3.11), normal-range BMI at switch (AHR 1.42, 95% CI 1.03-1.95), and lopinavir-based second-line regimen (AHR 1.72, 95% CI 1.15-2.57) were significant predictors of early time to viral resuppression after stratification by WHO stage and adherence level. Conclusion: Median time to viral re-suppression after switching to second-line ART was 10 months. In the stratified Cox model, female sex, baseline viral copies, second-line regimen type, and BMI at switch were statistically significant predictors of time to viral resuppression. Different stakeholders working on the HIV program should maintain viral resuppression by addressing significant predictors, and ART clinicians should consider ritonavir-boosted lopinavir based second-line ART for newly switched patients.