Serum 1,25-Dihydroxyvitamin D as a Biomarker of the Absence of Hypercalciuria in Postsurgical Hypoparathyroidism.
Hypercalciuria is an adverse event of postsurgical hypoparathyroidism treatment that can lead to renal complications. The collection of 24-hour urine to detect hypercalciuria is often considered unreliable.



The purpose of this study was to find useful predictive biomarkers of hypercalciuria in patients with permanent postsurgical hypoparathyroidism receiving treatment with oral calcium and calcitriol supplements.



The investigation was designed as a prospective cross-sectional study. An outpatient hospital clinic served as the study setting.



Fifty-four consecutive observations were made of 34 stable outpatients with postsurgical hypoparathyroidism taking oral calcium and calcitriol supplements, and 17 adult controls without hypoparathyroidism.



There were no interventions.



Hypercalciuria was defined as 24-hour urine calcium >300 mg.



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 vs 8.6 ± 0.5 mg/dL; P = nonsignificant), and serum parathyroid hormone (12.5 ± 5.7 vs 10.7 ± 6.8 pg/mL; P = nonsignificant). 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 cutoff 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 receiver operating characteristic curve was 0.797. No patients with serum 1,25-dihydroxyvitamin D levels of <33.5 pg/mL presented with hypercalciuria, regardless of the level of albumin-corrected serum calcium.



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 who are receiving treatment with oral calcium and calcitriol supplements.
Service of Endocrinology, Hospital Universitari Mútua de Terrassa, Terrassa, 08221 Spain.
Luis
L
García-Pascual
Service of Endocrinology, Hospital Universitari Mútua de Terrassa, Terrassa, 08221 Spain.
María José
MJ
Barahona
Service of Endocrinology, Hospital Universitari Mútua de Terrassa, Terrassa, 08221 Spain.
Verónica
V
Perea
Diabetes Research and Metabolism Unit, Institut de Recerca Hospital Universitari Vall d'Hebron, Barcelona, 08035 Spain; and.|Department of Medicine, Autonomous University of Barcelona, Barcelona, 08193 Spain.
Rafael
R
Simó
D000328:Adult; D015415:Biomarkers / Q000097:blood; D002118:Calcium / Q000097:blood*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053565:Hypercalciuria / Q000097:blood* / Q000175:diagnosis* / Q000209:etiology; D007011:Hypoparathyroidism / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016105:Parathyroidectomy / Q000009:adverse effects*; D011183:Postoperative Complications; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D015415:Biomarkers; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D002118:Calcium