Predictors of treatment failure on second-line antiretroviral therapy among adults in northwest Ethiopia: a multicentre retrospective follow-up study

Background: The number of patients using second-line antiretroviral therapy (ART) has increased over time. In Ethiopia, 1.5% of HIV infected patients on ART are using a second-line regimen and little is known about its effect in this setting. Objective: To estimate the rate and predictors of treatment failure on second-line ART among adults living with HIV in northwest Ethiopia. Setting: An institution-based retrospective follow-up study was conducted at three tertiary hospitals in northwest Ethiopia from March to May 2015. Participants: 356 adult patients participated and 198 (55.6%) were males. Individuals who were on second-line ART for at least 6 months of treatment were included and the data were collected by reviewing their records. Primary outcome measure: The primary outcome was treatment failure defined as immunological failure, clinical failure, death, or lost to follow-up. To assess our outcome, we used the definitions of the WHO 2010 guideline. Result: The mean +/- SD age of participants at switch was 36 +/- 8.9 years. The incidence rate of failure was 61.7/1000 person years. The probability of failure at the end of 12 and 24 months were 5.6% and 13.6%, respectively. Out of 67 total failures, 42 (62.7%) occurred in the first 2 years. The significant predictors of failure were found to be: WHO clinical stage IV at switch (adjusted HR (AHR) 2.1, 95% CI 1.1 to 4.1); CD4 count <100 cells/mm(3) at switch (AHR 2.0, 95% CI 1.2 to 3.5); and weight change (AHR 0.92, 95% CI 0.88 to 0.95). Conclusions: The rate of treatment failure was highest during the first 2 years of treatment. WHO clinical stage, CD4 count at switch, and change in weight were found to be predictors of treatment failure.