Magnitude and correlates of virological failure among adult HIV patients receiving PI based second line ART regimens in north western Tanzania; a case control study

BACKGROUND: With a growing access to free ART, switching of ART to second line regimen has also become common following failure of first line ART regimens. Patients failing on first line ART regimens have been shown to stand a high risk of failing on subsequent second line ART regimens. The magnitude of those who are failing virologicaly on second line ART is not documented in our setting. This study was designed to assess the magnitude and correlates of second line ART treatment failure. METHODS: A retrospective analysis of patients on second line ART for at least 1 year was done at Bugando care and treatment center. Information on demographic, clinical and laboratory data were collected and analyzed using STATA 11. The proportion of patients with Virological failure was calculated and potential correlates of virological failure were determined by logistic regression model. RESULTS: In total 197 patients on second line ART were included in this study and 24 (12.18%) of them met criteria for virological failure. The odds of having virological failure on second line ART were independently associated with age of less than 30 years (AOR = 12.5, p = 0.001), being on first line for less than 3 years (AOR = 6.1, p = 0.002) and CD4 at switch to second line ART of less than 200cells/μl (AOR = 16.3, p < 0.001). CONCLUSION: Virological failure among patients on second line ART is common. Predictors of virological failure in this study could assist in planning for strategies to improve the outcome of this subgroup of patients including close clinical follow up of patients at risk, a continued adherence intensification and a targeted resistance testing before switching to second line ART.