Estimating treatment coverage in South African ART clinics based on the time trend of the CD4 count distribution at ART initiation and a dynamical epidemiological model

Mazinu, Mikateko Cynthia (2013-12)

Thesis (MSc)--Stellenbosch University, 2013.

Thesis

ENGLISH ABSTRACT: HIV treatment coverage is currently inferred by dividing the number of people alive and on antiretroviral treatment (ART) by the number of individuals eligible for treatment, and estimates of these numbers are often made using dynamical epidemiological model. However, this approach ignores data on the distribution of CD4 cell counts at the time of ART initiation, and hence the inferred treatment coverage may be inconsistent with these CD4 count data. Here, we present a more inclusive method to estimate treatment coverage by incorporating the time trend of the CD4 count distribution at ART initiation in the dynamic epidemiological model. Data analysis of a cohort of 61 398 HIV infected adult patients who initiated treatment at eight South African ART clinics between 2004-2009 was conducted. Next, we used the results of the statistical analysis to adjust the parameters in the epidemiological model that governs the rate at which people from different CD4 cell count levels initiate ART. Lastly, we calibrate the model to reproduce the number of people alive and on ART. More than 80% of individuals started treatment very late, with CD4 count <200 cells/ L. A maximum of three years were delayed treatment after being eligible in all clinics involved in this study. The treatment coverage reached 61% in the eight clinics in our study. Methods to estimate ART coverage should make maximal use of CD4 cell count data at ART initiation, which may help to improve accuracy of the coverage estimates.

AFRIKAANSE OPSOMMING: Die dekking van HIV behandeling word huidiglik beraam deur die aantal mense op anti-retrovirale middels (ART) te deel deur die aantal mense wat die behandeling benodig, laasgenoemde beraam deur ’n dinamiese, epidemiologiese model. Hierdie benadering ignoreer egter data oor die verspreiding van CD4 tellings ten tyde van ART-inisiasie en dus kan die afgeleide behandeling dekking inkonsekwent wees met daardie CD4 telling data. Hier word ’n metode voorgestel wat behandeling dekking beraam deur die tendens van CD4 tellings ten tyde ART-inisiasie oor kalender tyd in die dinamiese model in te sluit.Data-analise van ’n groep van 61.398 MIV-besmette volwassenes pasiente wat behandeling begin by agt Suid-Afrikaanse kuns klinieke tussen 2004-2009 is uitgevoer. Volgende, ons gebruik die resultate van die statistiese analise die parameters in die epidemiologiese model wat bepaal die tempo waarteen mense van verskillende CD4 selle tel vlakke inisieer ART aan te pas. Ten slotte, ons kalibreer die model om voort te plant die berig aantal mense in die lewe en op die kuns. Meer as 80% individue behandeling begin baie laat, met ’n CD4-telling <200 selle L. ’N Maksimum van drie jaar vertraag behandeling nadat hy in aanmerking kom in alle klinieke betrokke in hierdie studie. Die behandeling dekking bereik 61% in die agt klinieke in ons studie. Metodes ART dekking te skat moet maksimale gebruik van CD4-telling data maak by ART-inisiasie, wat kan help om die akkuraatheid van die dekking skattings te verbeter.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/86774
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