Abstract Background: Data on parathyroid hormone (PTH) levels at hemodialysis (HD) initiation and during the first year of therapy are still scarce. We hypothesized that high baseline PTH levels contribute to more severe hyperparathyroidism during this period. Methods: Incident HD patients (n = 1,973) were divided into 3 groups according to PTH values ( 600 pg/mL). Results: PTH levels at baseline and at 1 year were 273 (133–508) and 255 (128–471) pg/mL, respectively (p = 0.291). PTH 600 pg/mL were found in 28.1, 53.5 and 18.4%, respectively, at baseline and 30.7, 52.5 and 16.8% after 1 year (p = 0.015). Younger age, absence of diabetes, high baseline alkaline phosphatase and PTH were independent risk factors for PTH > 600 pg/mL after 1 year of HD. Conclusion: High PTH at the beginning and after 1 year of HD indicate poor conservative management before and during dialysis, and put patients at risk of requiring parathyroidectomy later
