In HD patients, log-transformed ERFE was directly related to age (r = 0.13, p < 0.001), dialysis vintage (r = 0.12, p < 0.001), and PTH (r = 0.06, p = 0.08), and inversely associated with iron (r = −0.17, p < 0.001), hemoglobin (r = −0.16, p < 0.001), albumin (r = −0.13, p < 0.001), ferritin (r = −0.12, p < 0.001), cholesterol (r = −0.08, p = 0.01), and systolic blood pressure (r = −0.08, p = 0.01) but independent of BMI, diabetes, smoking, background CV comorbidities, phosphate, CRP, and Kt/V (P ranging from 0.11 to 0.98). Here, PTH is linked to diabetes mellitus.