A meta-analysis of these two studies found that antiretroviral therapy is strongly associated with a reduction in tuberculosis incidence in adults with baseline CD4 counts less than 200 cells/μl (HR 0.16, 95% CI 0.07 to 0.36; p-value for effect <0.001; p-value for heterogeneity = 0.609). Here, CD4 is linked to tuberculosis.