Identification of risk factors on secondary hyperparathyroidism undergoing long-term haemodialysis with vitamin D3

In order to evaluate the clinical outcome as well as the effect of vitamin D3 treatment on secondary hyperparathyroidism (SHPT) in the patients undergoing long-term dialysis therapy, we conducted a long-term follow-up survey on the demographic characteristics of 425 patients who were observed for more than 3 years. All patients were treated with daily 1 alpha (OH)D3 treatment after the initiation of dialysis. Among them the percentage of patients needing parathyroidectomy was 4.9%; aggravation of SHPT, 11.8%; an increase of the parathyroid hormone (PTH) level without radiographical abnormalities, 17.4%; stable, 56.2%; and a decrease of the PTH level, 9.7% at the final observation. The average PTH levels increased year by year irrespective of the difference of original renal disease. Gender, age at the start of dialysis, original renal disease, duration of dialysis treatment, the decade of starting dialysis, the degree of phosphate control, and the PTH level at starting dialysis were analysed as potential risk factors for SHPT, and assessed by multivariate analysis. Multivariate analysis revealed that only the terms of duration of dialysis and the PTH level at starting dialysis were the significant risks for developing overt SHPT. Logistic regression analysis revealed that the relative risk was significantly higher in the patients with more than 10 years history of dialysis and in those with the carboxyterminal PTH levels at the start of dialysis being more than 5 ng/ml. These results suggest that the treatment with daily low-dose vitamin D3 administration after dialysis initiation is imperfect; therefore some prophylactic therapy from the predialysis stage is necessary to prevent overt SHPT, which will occur after long-term haemodialysis.