Among women, CD4 < 100 as compared with CD4 ≥ 500 was associated with a HR for incident anemia of 10.64 (95% CI 8.41, 13.47), while for men the HR was 4.11 (2.60, 6.52); p-value for low CD4-sex interaction < 0.001; Supplemental Table 1). Here, CD4 is linked to anemia (phenotype).