Secondary hyperparathyroidism is a common complication found in patients with end-stage renal disease. High serum phosphate (PO4) content markedly influences synthesis and secretion of parathyroid hormone from parathyroid gland. To evaluate the relationships between serum phosphate reduction and changing of parathyroid hormone in hemodialysis patients, a perspective correlation study was conducted. Patients who undergoing hemodialysis at hemodialysis unit, the kidney foundation of Thailand at galayanivadhana building the Priests hospital participated in this study. The study was carried out from September 2002 to March 2003. Hemodialysis patients with parathyroid hormone (iPTH) level > 200 pg/ml and PO4 levels > 5.5 mg/dl were included in this study. There were 19 patients, aged 22-53 years old. The guidelines for hyperphosphatemia management were developed and used in these patients. The mean PO4 level decreased significantly from 7.05 ± 1.56 mg/dl to 4.19 ± 1.50 mg/dl (p < 0.05) at 3 months and decrease to 4.22 ± 1.42 mg/dl at 6 months after guideline implementation. However, significant reduction (40% from baseline) of mean iPTH from 549.85 ± 219.91 pg/ml to313.93 ± 166.16 pg/ml was seen after 6 months of guideline application. Using linear regression analysis, percent reduction of PO4 from baseline correlated with percent change of iPTH from baseline, r = 0.478, R2 = 0.228 (p < 0.05) at 3 months and r = 0.473, R2 = 0.224 (p < 0.05) at 6 months after guideline implementation. The linear equations are %changing of iPTH = 0.796 x (%reducing of PO4) -24.02 and %changing of iPTH = 0.658 x (%reducing of PO4) + 16.35, respectively.
