Modelling Trends of Cd4 Counts for Patients on Antiretroviral Therapy (Art) : After a Change in Who Guidelines in Kenya

Abstract

Background In resource-limited settings, changes in CD4 counts constitute an important component in patient monitoring and evaluation of treatment response as these patients do not have access to routine viral load testing. In this study, we quantified trends on CD4 counts in patients on highly active antiretroviral therapy (HAART) in a comprehensive health care clinic in Kenya between 2011 and 2017.We evaluated the rate of change in CD4 cell count in response to antiretroviral treatment. We further assessed factors that influenced time to treatment change focusing on baseline characteristics of the patients and different initial drug regimens used. The study involved 529 naïve HIV patients that had at least two CD4 count measurements for the period. The relationship between CD4 cell count and time was modeled using a semi parametric mixed effects model while the Cox proportional hazards model was used to assess factors associated with the first regimen change. Results The results demonstrated that CD4 counts increased over time and these trends were similar regardless of the treatment regimen used. Males were less likely to have drug regimens switch (adjusted hazard ratio (aHR) 0.5101, 95% CI: 0.1906 -1.3647) compared to females.Tenoforvir (TDF) based regimens had a lower drug substitution (aHR 0.2796, 95% CI: 0.0961-0.8629) compared to Zinovudine (AZT). Conclusion The backbone used was found to be associated with regimen changes among the patients with fewer switches being observed, with the use of TDF when compared to AZT. There was however no significant difference between TDF and AZT in terms of the change in CD4 count over time.