CST4 and coinfection: Among the 12 included indicators, 9 were laboratory examination indicators, including CD4+ T cell count, serum cystatin (Cys-C), standard bicarbonate (HCO3std), low-density lipoprotein cholesterol (LDL-C), creatinine clearance (Ccr), chloride (Cl), glutamyltransferase (GGT), monocytes-to-lymphocites ratio (Mono/Lymph) and hemoglobin-to-RDW ratio (HGB/RDW), 3 clinical comorbidity/co-infection including electrolyte disturbances, hypoproteinemia and cancer.