Mp583seasonal Profile of Ipth and Vitamin D in Chronic Hemodialysis Patients: Analysis of the Spanish Fresenius Medical Care Clinics

Abstract

Introduction and Aims:The secondary hyperparathyroidism associated with the CKD is a frequent complication which is modulated by several factors. In the general population it has been shown a seasonal variation of 25(OH)D with a reverse pattern of i-PTH levels. We investigated the seasonal variation of i-PTH and 25(OH)D in chronic hemodialysis patients over a multi-year period using data drawn from a large clinical data base in Spain, a conventional sunny country. Methods: All patients on chronic hemodialysis in any of the FMC Spanish facilities which had at least 2 i-PTH measurements between July 2011 and March 2015 were screened for their inclusion in this study. During this observational period serum levels of 25(OH)D, calcium and phosphorus were also recorded. The quarterly results were expressed as means ± SD and were compared using the ANOVA test plus the post-hoc Scheffé analysis. Further exponential smoothing models were used to study the i-PTH and 25(OH)D seasonal profile, adjusting this parameter by a simple seasonal model for i-PTH and by the Winters multiplicative seasonal model for 25(OH)D. Results: A total of 14.4 ± 10.1 and 4.9 ± 2.9, i-PTH and 25(OH)D determinations per patient were examined from 8670 patients treated in 64 Spanish FMC clinics. The i-PTH showed the higher levels during the winter (361±322) and the minimum during the summer (327±305; p<0.001) while 25(OH)D showed a reverse pattern (figure 1).