Increase in CD4 cell counts between 2 and 3.5 years after initiation of antiretroviral therapy and determinants of CD4 progression in India

Background : Estimation of CD4 cell count remains the primary monitoring tool in assessing efficacy or failure of Anti Retroviral Therapy (ART) under national program conditions in India. Aims : To study the average trajectory of CD4 cell count after two years of initiation of potent ART and to find the determinants of CD4 progression over time.
Settings and Design : A prospective cohort study under program conditions.
Materials and Methods : Adult ART naïve patients, receiving drug regimens consisting of two NRTIs and one NNRTI were studied for CD4 progression. Laboratory monitoring included the baseline and follow-up CD4 cell count, hemoglobin level and absolute lymphocyte count estimation. The change in CD4 cell count, hemoglobin and bodyweight was calculated from the baseline to the latest follow up measurements.
Statistical Analysis : Survival curve using Life table methods was plotted. Comparison between survival curves was done using Tarone-Ware statistics. Generalized estimating equation with exchangeable correlation structure was done to find the risk factors for CD4 progression.
Results : Among 7,934 HIV positive patients in the ART program, one-year cohort of 714 adult patients who had completed two consecutive follow-up CD4 values were assessed. Those with baseline CD4 < 100 had cumulative probability of survival 85%, 82%, 82% and 82% at 12, 24, 36 and 42 months respectively. Those who had baseline CD4 count between 100-199 had cumulative probability of survival 96%, 93%, 92% and 90% at 12, 24, 36 and 42 months respectively (P < 001). Lower the CD4 count ( < 100) lower the hemoglobin values.
Conclusions : CD4 progression continues two years after ART in patients who had base level > 100 cells. Early initiation of ART is necessary before CD4 crashing to < 100 cells for increasing the survival function.