Modification of antiretroviral therapy regimen: Incidence and predictors in two major HIV/AIDS treatment centers in the Southwest Region of Cameroon

Abstract

Background: The effectiveness of the first regimen of antiretroviral therapy (ART) is a major key to long-term success and sustainability of HIV treatment program. Aims: The objectives of this study were to determine the incidence rate, reasons, and factors associated with modification of initial ART regimen. Methods: A total of 502 patient files were reviewed. Modification of ART regimen was defined as either substitution or switch of a single drug in the regimen. Results: The total duration of follow-up was 629.8 person-years (PYs) over a median follow-up period of 37 months. About 92 (18.2%) of patients had their initial ART regimen modified, with a resulting incidence rate of modification at 14.6/100 PYs. Drug unavailability 49 (53.3%), drug toxicity 16 (17.4%), treatment failure 10 (10.9%), nonadherence 7 (7.6%), and concomitant condition 7 (7.6%) were common reasons for ART modifications. In the adjusted multivariate Cox proportional hazard model, the type of initial ART regimen (zidovudine/lamivudine (3TC)/efavirenz vs. tenofovir/3TC/nevirapine (NVP), aHR 4.78, 95% confidence interval [CI] [1.42, 16.12], P = 0.012), and duration on regimen (≤1 year vs. >3 years, aHR 4.11, 95% CI [1.02–9.22], P = 0.0001) were significantly associated with modification of initial ART regimen. Conclusion: Our findings indicate that the incidence rate of initial ART regimen modification was high. Hence, implementing better health systems to ensure a steady supply of drugs as well as early HIV diagnosis and ART initiation will reduce the rate of regimen change.