When the analysis was restricted to those with biopsy-proven KS (n = 378), the results were largely unchanged, with the exception that CD4 count ≤50 cells/mm3 was significantly associated with loss to follow-up (HR 2.35, 95 % CI: 1.29–4.27, p < 0.01). Here, CD4 is linked to Kaposi's sarcoma.