Abstract:

Objective: To analyze the associations of intact parathyroid hormone (iPTH) in patients with refractory secondary hyperparathyroidism (SHPT).  Methodology：One hundred and thirty four cases with end-stage renal disease and refractory SHPT treated with parathyroidectomy (PTX) were retrospectively studied. They were 67 males and 67 females with an average age of 49.5 ± 11.8 years old. Their clinical data including age, gender, primary causes of renal disease, therapeutic modalities, dialysis vintage of the patients before PTX were collected. The average dialysis vintage was 112±55.9 (0~252 months). The levels of serum iPTH, calcium, phosphorus and alkaline phosphatase (ALP) were detected before PTX. Multivariate linear regression was used to analyze the relationship between serum iPTH levels and age, gender, vintage, corrected serum calcium, serum phosphorus and ALP levels. Results：Of the 134 cases, 15(11.2%) were 15 years or more , 23 (17.2%)  were 10-15 years, 75 (55.9%) were 5~10 years, and 21 (15.7%）were 5 years or less of dialysis vintage. The level of serum iPTH (mean±SD) before PTX was (1958±785) pg/ml (479~4200 pg/ml). The level of serum phosphorus (mean±SD) before PTX was (2.27±0.59) mmol/L (0.64~4.17 mmol/L). The corrected serum calcium levels (mean±SD) before PTX was (2.56±0.22) mmol/L (1.96~3.35 mmol/L). The median value for serum ALP concentrations before PTX was 373 IU/L (41~2752 IU/L). Multivariate linear regression showed that dialysis vintage [B=4.8, 95% confidence interval (CI) 2.31~7.36, P=0.000], serum phosphorus levels (B=437, 95% CI 154.16~719.92，P=0.003), serum ALP concentrations (B=0.5, 95% CI 0.23~0.80，P=0.000) were associated with serum iPTH before PTX. That meant before PTX, serum iPTH was increased by 4.8 pg/ml with increasing of one month of dialysis vintage. The level of serum iPTH was increased by 437 pg/ml with increasing of one mmol/L of serum phosphorus. The serum iPTH was increased by 0.5 pg/ml with increasing of one IU/L of serum ALP. Conclusion：The serum iPTH in patients with refractory SHP was correlated with dialysis vintage, serum phosphorus and ALP levels before PTX, while it was not correlated with gender, age and corrected serum calcium levels. Strictly control of serum phosphorus might be more important to prevent refractory SHPT.