Senescent CD4 (KLRG1+/CD28−) and CD8 T cells were also associated with readmission (p = 0.014 and p = 0.013, respectively), and senescent CD4 T cells were predictive of total hospital time (p = 0.003). TEMRA CD4 T cells were significantly associated with frailty (p = 0.015) and sarcopenia (p = 0.011). Here, CD4 is linked to sarcopenia.