Incidence and Determinants of Lost to Follow Up Among Patients on Antiretroviral Therapy

Abstract

Death is ofttimes ignored in lost to follow up studies yet it is a competing event in such cases as it is informative of its probability.A couple of studies have been done on incidence and determinants of lost to follow up however solid estimates may be found if death as a competing event is taken into account rather than censoring. The goal of the study seeks to nd out the incidence and determinants of lost to follow up with and without death as a competing event. Cox proportional hazards model and Fine-Gray’s subdistribution hazards model were employed to model the outcome of the determinants on lost to follow up. Kaplan-Meier graph was done to describe the probability of lost to follow up in the cox proportional hazards model while cumulative incidence function was done to describe the incidence of lost to follow up while taking death as competing event into account.Each variable was tested for the assumption of proportional hazards before inclusion in the nal model using Schoenfeld residuals. 1047 patients ( 15 years) were included in the study. The overall lost to follow up rate was 14% with 2.4 per 100-person years incidence rate. Being male, having CD4 count of < 200 mm3 and a younger age (15-30 years) were signi cant determinants of lost to follow up, hence there is need to give extra attention to these groups of people in order to improve HIV care service delivery