The sub-hazard ratio of attrition was lower amongst those who had a CD4 cell count recorded at baseline (cSHR = 0.63, 95%CI: 0.46–0.85) and in those in the later stages of HIV infection (stages II, III and IV versus stage I: cSHR = 0.60, 95%CI: 0.45–0.80). Here, CD4 is linked to HIV infectious disease.