Serum 1,25-dihydroxyvitamin D as a biomarker of the absence of hypercalciuria in postsurgical hypoparathyroidism.

Serum 1,25-dihydroxyvitamin D as a biomarker of the absence of hypercalciuria in postsurgical hypoparathyroidism.

J Clin Endocrinol Metab. 2016 Nov 4;:jc20162987

Authors: García-Pascual L, Barahona MJ, Perea V, Simó R

Abstract
CONTEXT: Hypercalciuria is an adverse event of postsurgical hypoparathyroidism treatment which can lead to renal complications. The collection of 24-hour urine to detect hypercalciuria is often considered unreliable.
OBJECTIVE: To find useful predictive biomarkers of hypercalciuria in patients with permanent postsurgical hypoparathyroidism under treatment with oral calcium and calcitriol supplements.
DESIGN: Prospective cross-sectional study.
SETTING: Outpatient hospital clinic.
PATIENTS: Fifty-four consecutive observations from 34 stable outpatients with postsurgical hypoparathyroidism taking oral calcium and calcitriol supplements, and 17 adult controls without hypoparathyroidism.
INTERVENTION: There were no interventions.
MAIN OUTCOME MEASURE: Hypercalciuria was defined as 24-hour urine calcium above 300 mg.
RESULTS: Patients without hypercalciuria (n=21) vs. those with hypercalciuria (n=33) had lower levels of serum 1,25-dihydroxyvitamin D (33.5+11.9 pg/ml vs. 45.8+9.5 pg/ml; p<0.001), similar albumin-corrected serum calcium (8.3+0.5 mg/dl vs. 8.6+0.5 mg/dl; p:ns), and serum parathyroid hormone (12.5+5.7 vs. 10.7+6.8; p:ns). Multiple linear regression analysis showed an independent relationship between 1,25-dihydroxyvitamin D and urinary calcium excretion (B= 6.2+1.423; p<0.001). A cut-off value of 33.5 pg/ml for serum 1,25-dihydroxyvitamin D to predict the absence of hypercalciuria had 100% sensitivity and 63.6% specificity, and the area under the ROC curve was 0.797. No patients with serum 1,25-dihydroxyvitamin D under 33.5 pg/ml presented hypercalciuria, whatever the level of albumin-corrected serum calcium.
CONCLUSIONS: Routine measurement of serum 1,25-dihydroxyvitamin D may be useful as a biomarker to predict the absence of hypercalciuria in patients with permanent postsurgical hypoparathyroidism under treatment with oral calcium and calcitriol supplements.

PMID: 27813709 [PubMed - as supplied by publisher]

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