Factors often reported to increase risk anemia include ART regimens containing zidovudine, more advanced disease stage or low CD4+ count, nutritional status or body mass index <18.5 kg/M2, female sex, duration of HAART, presence of opportunistic infections, and low baseline hemoglobin level [8, 12, 13, 15–18, 21, 30, 39–42]. This evidence concerns the gene CD4 and anemia (phenotype).