PTH and chronic kidney disease: In the CKD cohort, log-transformed serum ERFE was directly related to PTH (r = 0.13, p = 0.002), age (r = 0.11, p = 0.002), CRP (r = 0.10, p = 0.009), and background CV comorbidities (r = 0.09, p = 0.02) and inversely related to iron (r = −0.18, p < 0.001), hemoglobin (r = −0.12, p = 0.002), and cholesterol (r = −0.11, p = 0.003).