AUTHOR=Daimon Makoto , Fujita Tomoyuki , Murabayashi Masaya , Mizushiri Satoru , Murakami Hiroshi , Nishiya Yuki , Tanabe Jutaro , Matsuhashi Yuki , Yanagimachi Miyuki , Tokuda Itoyo , Sawada Kaori , Ihara Kazushige
TITLE=Exacerbation of Hyperparathyroidism, Secondary to a Reduction in Kidney Function, in Individuals With Vitamin D Deficiency
JOURNAL=Frontiers in Medicine
VOLUME=7
YEAR=2020
URL=https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2020.00221
DOI=10.3389/fmed.2020.00221
ISSN=2296-858X
ABSTRACT=Aims/Introduction: Chronic kidney disease (CKD)-mineral and bone disorders (CKD-MBD) are an adverse outcome derived from decreases in kidney function, where abnormality of serum concentrations of calcium (Ca), phosphorus, parathyroid hormone (PTH), and vitamin D can be seen simultaneously. To identify individuals at risk for CKD-MBD or secondary hyperparathyroidism, the relationships between estimated glomerular filtration rate (eGFR) and serum PTH concentration were evaluated, allowing for confounding factors, in particular vitamin D status, in a general Japanese population.
Materials and Methods: Nine-hundred-and-thirty participants in the population-based Iwaki study conducted in 2016 who were not on drugs affecting mineral metabolism nor hemodialysis, were included in the study (326 men and 604 women; age: 55.4 ± 15.9 years).
Results: Regression analysis showed a significant correlation between eGFR and serum intact PTH concentration, after adjustment for possible confounding factors (β = −0.122, p < 0.001). The smoothed spline curve applied for the correlation analysis revealed a biphasic correlation, with a division at an eGFR of ~60 mL/min/1.73 m2, below which the correlation coefficient was higher (β = −0.405, p < 0.001). Stratification on the basis of vitamin D status showed that the correlation was present only in participants with vitamin D deficiency (25-dihydroxyvitamin D3: <15 pg/mL) (β = −0.154, p < 0.001).
Conclusions: These results indicate that a reduction in eGFR is a significant risk factor for an increase in serum PTH concentration when it is <60 mL/min/1.73 m2 and vitamin D is deficient, in the general Japanese population.