High prevalence of hyperparathyroidism among peritoneal dialysis patients:A review of 176 patients

Objectives: Parathyroid dysfunction continues to produce significant morbid ity in dialysis patients. Since the introduction of low calcium dialysate f or peritoneal dialysis (PD), no large studies have been done to determine t he prevalence of parathyroid dysfunction in these patients. This study was done to assess the prevalence of parathyroid disease in the PD population a nd to determine the risk factors associated with this dysfunction. Design: We analyzed data on 176 patients who received PD at a single center between August 1998 and February 1999. Clinical data, laboratory variables related to parathyroid function, and data pertaining to dialysis treatment and weekly drug dosing were obtained for each patient on two different occ asions, approximately 3 months apart. Variables predictive of the developme nt of parathyroid dysfunction were calculated by univariate and multivariat e logistic regression analysis. Results: Two-thirds of the patients surveyed had an abnormal intact parathy roid hormone (iPTH) level: 47% had an iPTH level more than three times norm al, the mean was 54.6 +/- 35.4 pmol/L; 23% had an iPTH value below the uppe r limit of normal, here the mean was 3.6 +/- 1.8 pmol/L. Diabetic patients had lower iPTH levels (22.2 +/- 28.4 pmol/L) than nondiabetics (33.9 +/- 34 .8 pmol/L) (p = 0.02). On multivariate regression analysis, we found that a ge, duration of dialysis, Kt/V, serum bicarbonate, and serum ionized calciu m levels did not significantly affect parathyroid function. Hyperphosphatem ia was the only factor that was associated with the development of secondar y hyperparathyroidism in this study population (p = 0.029). Conclusion: There is a high prevalence of hyperparathyroidism in the curren t PD population. Phosphate control is suboptimal and hyperphosphatemia is a n independent risk factor for the development of hyperparathyroidism.