Laboratory criteria for the persistence of secondary hyperparathyroidism in patients with chronic kidney disease

Abstract

Secondary hyperparathyroidism is a complication of chronic kidney disease in both the non-dialysis and dialysis stages. Even modern advances in drug therapy cannot change the fact that most CKD patients require surgical treatment. The purpose of the treatment of SHPT is to normalize mineral metabolism, prevent bone diseases and prevent extraosseous manifestations. One of the methods of surgical treatment is subtotal parathyroidectomy. Persistence or recurrence of the disease occurs in 5-30% of cases.

Purpose of the study. To determine laboratory criteria for the persistence of SHPT in patients with chronic kidney disease on the second day after parathyroidectomy.

Materials and methods. The study involved 118 patients with end-stage CKD with prolonged renal replacement therapy. All patients had clinical and laboratory signs of secondary hyperparathyroidism. In the period from 2009 to 2019, patients underwent subtotal parathyroidectomy. The patients were divided into two groups. This division was based on the presence of persistence or recurrence of the disease. The main group included 20 patients with laboratory signs of SHPT persistence; the comparison group included 98 patients without signs of disease’s persistence.

Results. Analysis of changes in laboratory parameters in patients with persistence and in patients without signs of disease’s persistence revealed certain differences in their postoperative level. In all 118 cases, there was a significant decrease in PTH in the postoperative period - from 31.5 to 99.6%. Using ROC-analysis, a study was carried out of the possibility of using the degree of PTH reduction as a predictor of the persistent course of SHPT and the optimal cut-off thresholds were established. A decrease in the postoperative level of PTH by 90.9% or more indicates an effective PTE. The maximum value of the test specificity (1.000 (0.968; 1.000)) is achieved when the PTH reduction is 76.0%. At the same time, the maximum value - 1.000 (0.968; 1.000) - reaches the predictive value of a positive test result.

Conclusions. Using the subtotal parathyroidectomy in our study, the persistent of SHPT occurred in 16.9% of cases. A decrease in PTH levels on the second day after surgery less than 76% comparatively to the preoperative level should be considered as a predictor of the development of disease persistence. A reduction in PTH of more than 90.9% may be an indication of sustained remission.