Incidence and determinants of change of initial HAART regimen among outpatient HIV infected adults at the University of Teaching Hospital in Lusaka, Zambia

Abstract

Introduction: Durability of the first highly active antiretroviral therapy (HAART) regimen is a major key to long term access, scalability and sustainability of an HIV treatment program. It is important to know the incidence rate of initial HAART regimen change, the reasons and factors associated with change of the initial HAART regimen in Zambia. This study was designed to determine the incidence rate and factors associated with change of initial HAART regimen at the University Teaching Hospital (UTH) from 1st January 2008 to 31st December 2011.Methodology: This research was a hospital based retrospective cohort study of adult HIV/AIDS patients who were initiated on HAART from 1st January 2008 to 31st December 2011 at UTH adult outpatients ART clinic. Medical charts were reviewed for demographic information, change or no change of initial HAART regimen, type of initial HAART regimen, date of initiation, date of change, and reasons or factors of change. The incidence rate of change of initial HAART regimen was calculated. We assessed characteristics of patients who changed their initial HAART regimen and reasons for change. Cox proportional hazard models were performed to analyze factors associated with change of initial HAART regimen. Results: Incidence rate of change and factors associated with change of initial HAART regimen was obtained from 341 medical charts. 154/341 (45.2%) of patients had their initial HAART regimen changed. The incidence rate of change was 17.5 per 100 person-years. The proportion of change due to treatment failure was 1.8%. The most common reasons for change of initial HAART regimen were drug unavailability (stocks out and drugs cost) 46.1%, non-adherence 19% and renal toxicity 5.2%. The type of initial HAART regimen was significantly associated with change of initial HAART regimen.Conclusions:It is important to evaluate reason-specific trends in the incidence of change of initial HAART regimen in order to better understand the determinants of changes. Given the findings that drug unavailability was responsible for nearly half of all changes of initial HAART regimens, better health systems need to be implemented to ensure steady supply of drugs to patients. Also there is a need for research that helps to develop better screening modalities for renal toxicity, considering that tenofovir is part of the recommended first line regimen in Zambia.