Comparison of CD4+ T-Cell changes in response to highly active antiviral therapy (HAART) in adolescents and children enrolled at Parirenyatwa Hospital Family Care Centre (2005-2010) - Secondary Data Analysis

Abstract

Background In general, there is an increase in CD4 cell count after initiating on HAART. Despite an increasing trend of access to HAART there is a paucity of studies examining the changes in CD4 count over time in Zimbabwe and also no study has been done at PHFCC specifically comparing children and adolescents at the clinic. The PAP study data has not been analyzed to compare how CD4 count changes over time between different age groups and to find out the factors which predicts CD4 count response after initiating on HAART. The study aims to determine the factors associated with changes in CD4 count in adolescents and children and to compare the changes between these two age groups over time. Methodology Out of 2200 HIV infected children and adolescents who have been enrolled into HIV/AIDS care between January 2004 and December 2012, a total of 512 subjects who met the inclusion criteria were selected for this secondary data analysis study. Differences between groups in CD4 cell response at different time points was assessed using Wilcoxon rank-sum test. Mixed effects model was used to compare the pattern of changes in CD4 count over time between adolescents and children and to identify the factors which are associated with changes in CD4 count after HAART initiation. iii Results A total of 512 subjects were selected for the study. More (59.6 %) of the subjects were adolescents and the female gender (52.3%) was mostly represented. The change in CD4 count in response to HAART between adolescents and children was different. The median (IQR) baseline CD4 count for children was 171.5 (51-298) cells/mm3 and 145 (50-254) cells/mm3 for adolescents (p=0.087). The response in children was significantly higher after 18 months on treatment compared to adolescents (p=0.004). Baseline CD4 counts and age group was found to predict the changes in the square root of CD4 count over time in the multivariate analysis. The increase in the square root of CD4 count over time for those who initiate HAART at adolescence stage were 0.0853 times less when compared to those initiated whilst they were still children (p=0.037) adjusting for other variables. Adjusting for other baseline variables, subjects with CD4 cell count less than 100cells/mm3 had a greater increases (beta=0.501, p<0.001) in the square root of CD4 cell count when compared to those with baseline CD4 count of more than 300cells/mm3. Subjects with baseline CD4 count of 100 to 200 cells/mm3 had a greater increase in the square root of CD4 count over time as compared to those with baseline CD4 count above 300cells/mm3 adjusting for other variables ( beta=0.340, p<0.001). Conclusion The change in CD4 count in response to HAART between adolescents and children was different. The baseline variables which were significantly associated with an increase in CD4 count over time were baseline CD4 cell count and age group after controlling for other independent variables.