Speaker Biography

Tilahun Asena

Tilahun Ferede Asena is a PhD candidate at Department of Statistics, College of Natural and Computational Sciences, Hawassa University, Ethiopia.  He holds his Masters in Applied Statistics in 2012 and a Bachelor Degree in Statistics in 2009 at Hawassa University, Ethiopia. Before coming to Hawassa University, he served as a Lecturer from July 2012-October 2014 and worked as a Graduate Assistant from September 2009-June 2010 at Arba Minch University. Tilahun published several papers on international Journals.  His research interests are in Disease Progression Modelling.


The introduction of highly active anti-retroviral therapy (HAART) for the treatment of AIDS patients has made significant improvements in patient survival and quality of life during late 1990 (WHO, 2008). Thus, this work focused on estimation of HIV/AIDS Disease progression using parametric Semi-Markov Models and to assess factors affecting HIV/AIDS Disease progression of individuals who are following ART therapy during 2008-2015 with time-dependent covariates in Yirgalim General Hospital, Ethiopia. The findings of this study indicate that HIV/AIDS Disease progression can vary greatly according to patient’s gender, Body Mass Index, and Weight Gain/Loss during the follow-up, Age of the patient and other unknown factors associated. By including time-dependent covariates, we show that these factors had significant differences in HIV/AIDS Disease progression. Finally, these results underscore the need for selecting appropriate waiting time distribution for each transition in order to accurately estimate disease progression. In our study, we found that Parametric Semi-Markov models are a powerful approach for studying chronic diseases and using appropriate waiting times for specific transitions of disease progression.