Aim: To evaluate the parathyroid ultrasonography and define parameters that can predict poor response to treatment in patients with secondary hyperparathyroidism due to renal failure.
Methods: This cohort study evaluated 85 patients with chronic kidney disease stage V with parathyroid hormone levels above 800 pg/mL. All patients underwent ultrasonography of the parathyroids and the following parameters were analyzed: Demographic characteristics (etiology of chronic kidney disease, gender, age, dialysis vintage, vascular access, use of vitamin D), laboratory (calcium, phosphorus, parathyroid hormone, alkaline phosphatase, bone alkaline phosphatase), and the occurrence of bone changes, cardiovascular events and death. The χ(2) test were used to compare proportions or the Fisher exact test for small sample frequencies. Student t-test was used to detect differences between the two groups regarding continuous variables.
Results: Fifty-three patients (66.4%) had parathyroid nodules with higher levels of parathyroid hormone, calcium and phosphorus. Sixteen patients underwent parathyroidectomy and had higher levels of phosphorus and calcium × phosphorus product (P = 0.03 and P = 0.006, respectively). They also had lower mortality (32% vs 68%, P = 0.01) and lower incidence of cardiovascular or cerebrovascular events (27% vs 73%, P = 0.02). Calcium × phosphorus product above 55 mg(2)/dL(2) [RR 1.48 (1.06, 2.08), P = 0.03], presence of vascular calcification [1.33 (1.01, 1.76), P = 0.015] and previous occurrence of vascular events [RR 2.25 (1.27, 3.98), P < 0.001] were risk factors for mortality in this population. There was no association between the occurrence of nodules and mortality.
Conclusion: The identification of nodules at ultrasonography strengthens the indication for parathyroidectomy in patients with secondary hyperparathyroidism due to renal failure.
Keywords: Alkaline phosphatase; Bone alkaline phosphatase; Calcium; Chronic kidney disease; Parathyroid hormone; Parathyroid ultrasonography; Phosphorus; Secondary hyperparathyroidism.