Older patients had a lower proportion who had extreme immunodeficiency (CD4 cell count <50 cells/μL) at baseline (14.9% vs. 19.6%; P<0.0001) Older patients had a slightly lower proportion with advanced (stage IV) World Health Organization clinical stage disease (10.6% vs. 12.0%; P<0.0001) as well as a lower proportion who were receiving tuberculosis treatment at baseline (11.4% vs. 13.0%; P<0.0001). This evidence concerns the gene CD4 and immune system disorder.