**5.4 PTH and mortality rate in patients with CKD**

The triad of altered calcium and phosphorus metabolism and high plasma PTH level represents one of the major challenges during the management of patients with CKD due to their adjuvant harmful consequences on various body tissues and their correlation to the high mortality rate commonly observed in patients with CKD with the leading cause being the cardiovascular disease. These disorders of metabolism are associated with accelerated vascular calcification involving various arteries including coronary arteries. Both hypercalcemia and hyperphosphatemia that are present in patients with prolonged secondary hyperparathyroidism seen in patients with CKD are associated with medial calcification. Furthermore, skin and soft tissue necrosis and ulceration, known as uremic arteriolopathy or calciphylaxis, is an uncommon serious complication of secondary hyperparathyroidism and has an eight-fold increase in mortality [54]. Many studies have suggested PTH as an independent risk factor for renal death in patients with CKD whether on renal replacement therapy or not [55, 56]. The severity of increase of PTH prior to hemodialysis has been shown to predict more difficulty in decreasing PTH afterwards [57]. It is of great importance to notify that a low or even normal concentration of PTH is thought to be associated with poor prognosis as well. KDIGO recommend

### *Prognostic Value of Serum Parathyroid Hormone in Patients with End-Stage Renal Disease DOI: http://dx.doi.org/10.5772/intechopen.100229*

plasma concentration of PTH to be 2–9 times the upper normal limit [57]. A gradual decrease of PTH to the target level has been associated with a significant decrease in mortality rate. Patients with concomitant high plasma concentrations of PTH and phosphorus have shown a higher risk of mortality [58]. The residual renal function seems to be a determinant factor for the risk of mortality in patients with high plasma PTH. Many clinicians are attracted to normalize PTH using various modalities including vitamin D, phosphate binders and calcimimetics but their benefit in reducing the mortality rate is questioned depending on various clinical studies that failed to confirm an association between the improvement in biochemical and hematological parameters and reduction of the risk of mortality rate suggesting more precautions for the use of these modalities in an attempt to reduce the risk of renal death [59]. In contrast, a recent meta-analysis study enrolling around 25000 patients has suggested a significant beneficial effect of parathyroidectomy in reducing mortality rate explained by controlling blood pressure and improvement of left ventricular hypertrophy [60].

All these findings highlight the importance of plasma PTH in the management of patients with CKD making it a cornerstone in the course of the illness as it affects various tissues and organs in the body in addition to its confirmed correlation with the risk of mortality in such patients.
