Comparative study of secondary hyperparthyroidism according to the mode of dialysis in patients with end-stage renal disease

Jung, In Hyun; Lee, Ho Yung; Lim, Sung Kil; Choi, Kyu Hun; Yoon, Soo Young; Han, Dae Suk; Kang, Shin Wook

Abstract

BACKGROUND: It has been well known that parathyroid hormone (PTH) plays an important role as a uremic toxin in patients with end-stage renal disease, and develops many abnormalities in musculo-skeletal, nervous, cardiovascular and immune systems, which contributes mortalities and morbidities of the patients. Recently, many researches have reported various clinical significances of PTH. Especially, there is some suggestion that parathyroid hormone level could be used as a new marker of survival in uremic patients. The purpose of this study was to assess the prevalence of secondary hyperparathyroidism according to the modality and duration of dialysis in patients with ESRD and to determine the factors that attribute to increasing iPTH levels.
METHODS
From January 1996 to June 2001, 328 dialysis patients who have received maintenance hemodialysis or peritoneal dialysis more than 6 months in Severance Hospital were included in this study. We studied retrospectively by reviewing their medical records and defined hyperparathyroidism, if iPTH level was increased more than three times of upper normal limit.
RESULTS
The number of patients with iPTH level greater than 195 pg/mL was 170(49.8%): HD 76 (53.9%), CAPD 94 (50.2%). The average level of iPTH was increased with dialysis duration in both groups, and also, significantly more increased in hemodialysis group than CAPD more than 40months after the beginning of dialysis. The iPTH level was negatively correlated with age and creatinine clearance by simple and multiple regression analysis in both dialysis groups. Alkaline phosphatase and serum phosphorus levels had positive correlation with the level of iPTH in both CAPD and HD patients. Cox regression analysis showed an increment of development of secondary hyperparathyroidism with duration of dialysis. In patients on HD, the prevalence of secondary hyperparathyroidism was much higher than those on CAPD with statistical significance in patients on dialysis more than 40 months.
CONCLUSION
In this study, iPTH level was correlated with age, serum phosphorus level and residual renal function at the initiation of dialysis in both groups. And also, in patients on HD, the average level of iPTH and the prevalence of secondary hyperparathyroidism were much higher than those on CAPD with statistical significance. So, we suggest that early dialysis and intensive attention to serum phosphorus level would be required in patients with ESRD for preventing the secondary hyperparathyroidism and more careful monitoring for serum calcium, phosphorus and parathyroid hormone with adequate treatments would be needed especially in hemodialysis patients.