CD4 and AIDS: A higher CD4+ T-cell count (HR, 0.99 per 50 cells/mm3 increase [95% CI, .98–.99]), coadministration of TDF with an NNRTI (HR, 0.56 [95% CI, .50–.63]), and a previous AIDS-defining event (HR, 0.83 [95% CI, .77–.90]) were associated with a decreased likelihood of discontinuing TDF therapy (Supplementary Table 1).