Practice patterns for chronic hypoparathyroidism: data from patients and physicians in France

Context. Recent guidelines have provided recommendations for the care of patients with chronic hypoparathyroidism. Very little is known about actual physicians’ practices or their adherence to such guidelines. Objective. To describe the practice patterns and their compliance with international guidelines. Design. Cohort studies: Épi-Hypo (118 Physicians and 107 patients, from 09/2016 to 12/2019) and ePatients (110 patients, November 2019). Methods. Internet-based cohorts involving all settings at a nationwide level (France). Participants were i) physicians treating patients with chronic hypoparathyroidism and patients with chronic hypoparathyroidism either participating in the ii) Épi-Hypo study (Épi-Hypo 2019 patients) or iii) Hypoparathyroidism France, the national representative association (ePatients). Results. The physicians’ specialties were mainly endocrinology (61%), nephrology (28%), family medicine (2.5%), pediatrics (2.5%), rheumatology (2%) or miscellaneous (4%). Forty-five percent were practicing in public universities. The median number of pharmaceutical drug classes prescribed was 3 per patient. The combination of active vitamin D and calcium salt was given to 59% and 58% of ePatients and Épi-Hypo 2019 patients, respectively. Eighty-five percent of ePatients and 87% of physicians reported monitoring plasma calcium concentrations at a steady state at least twice a year. In 32% and 26% of cases, respectively, ePatients and physicians reported being fully in accordance with international guidelines that recommend targeting symptoms, plasma calcium and phosphate values, and urine calcium excretion. Conclusions. The care of patients with chronic hypoparathyroidism involves physicians with very different practices, so guidelines should include and target not only endocrinologists. Full adherence to the guidelines is low in France.

Urinary calcium indices in primary hyperparathyroidism (PHPT) and familial hypocalciuric hypercalcaemia (FHH): which test performs best?

AimPrimary hyperparathyroidism (PHPT) is much more common than familial hypocalciuric hypercalcaemia (FHH), but there is considerable overlap in biochemical features. Urine calcium indices help with the differential diagnosis, but their reliability in making this distinction is not clear. The aim of this study was to compare urinary calcium values in patients with PHPT and FHH.MethodsThis was a case–control study of patients with PHPT who had successful surgery and genetically proven FHH between 2011 and 2016. Due to low FHH numbers, patients from neighbouring hospitals and outside study period (2017–2019) were allowed to improve power. Data on demographics and urinary calcium were obtained from electronic records and compared between the two groups.ResultsDuring the study period, 250 patients underwent successful PHPT surgery, while in the FHH arm, 19 genetically proven cases were included. The median (IQR) 24-hour urine calcium excretion (UCE) in the PHPT group was 8.3 (5.6–11.2) mmol/24 hours compared with 3.2 (2.1–6.1) mmol/24 hour in the FHH group (p<0.001). Median (IQR) calcium to creatinine clearance ratio (CCCR) in the PHPT and FHH groups was 0.020 (0.013–0.026) and 0.01 (0.002–0.02), respectively (p=0.001). The sensitivity of urinary tests for PHPT was 96% for UCE (cut-off ≥2.5 mmol/24 hour) and 47% for CCCR (cut-off >0.02). The specificity of the urinary tests for FHH was 29.4% for UCE (cut-off <2.5 mmol/24 hour) and 93% for CCCR (cut-off <0.02).Conclusions24-hour UCE is more sensitive in diagnosing PHPT; however, it is less specific in ruling out FHH as compared with CCCR, when the cut-offs suggested by the International guidelines from the fourth international workshop are used. A significant proportion of patients with PHPT would have also required genetic studies if the guidelines were followed.

Safety of High-Dose Vitamin D Supplementation: Secondary Analysis of a Randomized Controlled Trial

Context More than 3% of adults report vitamin D intakes of 4000 IU/day or more, but the safety of this practice is unknown. Objective The objective of this work is to establish whether vitamin D doses up to 10 000 IU/day are safe and well tolerated. Design The Calgary Vitamin D Study was a 3-year, double-blind, randomized controlled trial. Setting A single-center study was conducted at the University of Calgary, Canada. Participants Participants included healthy adults (n = 373) ages 55 to 70 years with serum 25-hydroxyvitamin D 30 to 125 nmol/L. Interventions Participants were randomly assigned 1:1:1 to vitamin D3 400, 40 000, or 10 000 IU/day. Calcium supplementation was initiated if dietary calcium intake was less than 1200 mg/day. Main Outcome Measures In these prespecified secondary analyses, changes in serum 25-hydroxyvitamin D, calcium, creatinine, 24-hour urine calcium excretion, and incidence of adverse events were assessed. Between-group differences in adverse events were examined using incident rate differences and logistic regression. Results Of 373 participants (400: 124, 4000: 125, 10 000: 124), 49% were male, mean (SD) age was 64 (4) years, and 25-hydroxyvitamin D 78.0 (19.5) nmol/L. Serum calcium, creatinine, and 24-hour urine calcium excretion did not differ between treatments. Mild hypercalcemia (2.56-2.64 mmol/L) occurred in 15 (4%) participants (400: 0%, 4000: 3%, 10 000: 9%, P = .002); all cases resolved on repeat testing. Hypercalciuria occurred in 87 (23%) participants (400: 17%, 4000: 22%, 10 000: 31%, P = .01). Clinical adverse events were experienced by 365 (97.9%) participants and were balanced across treatment arms. Conclusions The safety profile of vitamin D supplementation is similar for doses of 400, 4000, and 10 000 IU/day. Hypercalciuria was common and occurred more frequently with higher doses. Hypercalcemia occurred more frequently with higher doses but was rare, mild, and transient.

Claudin-14 Gene Polymorphisms and Urine Calcium Excretion

Background and objectivesClaudin-16 and -19 are proteins forming pores for the paracellular reabsorption of divalent cations in the ascending limb of Henle loop; conversely, claudin-14 decreases ion permeability of these pores. Single-nucleotide polymorphisms in gene coding for claudin-14 were associated with kidney stones and calcium excretion. This study aimed to explore the association of claudin-14, claudin-16, and claudin-19 single-nucleotide polymorphisms with calcium excretion.Design, setting, participants, & measurementsWe performed a retrospective observational study of 393 patients with hypertension who were naïve to antihypertensive drugs, in whom we measured 24-hour urine calcium excretion; history of kidney stones was ascertained by interview; 370 of these patients underwent an intravenous 0.9% sodium chloride infusion (2 L in 2 hours) to evaluate the response of calcium excretion in three different 2-hour urine samples collected before, during, and after saline infusion. Genotypes of claudin-14, claudin-16, and claudin-19 were obtained from data of a previous genome-wide association study in the same patients.ResultsThirty-one single-nucleotide polymorphisms of the 3′ region of the claudin-14 gene were significantly associated with 24-hour calcium excretion and calcium excretion after saline infusion. The most significant associated single-nucleotide polymorphism was rs219755 (24-hour calcium excretion in GG, 225±124 mg/24 hours; 24-hour calcium excretion in GA, 194±100 mg/24 hours; 24-hour calcium excretion in AA, 124±73 mg/24 hours; P<0.001; calcium excretion during saline infusion in GG, 30±21 mg/2 hours; calcium excretion during saline infusion in GA, 29±18 mg/2 hours; calcium excretion during saline infusion in AA, 17±11 mg/2 hours; P=0.03). No significant associations were found among claudin-16 and claudin-19 single-nucleotide polymorphisms and calcium excretion and between claudin-14, claudin-16, and claudin-19 single-nucleotide polymorphisms and stones. Bioinformatic analysis showed that one single-nucleotide polymorphism at claudin-14 among those associated with calcium excretion may potentially influence splicing of transcript.ConclusionsClaudin-14 genotype at the 3′ region is associated with calcium excretion in 24-hour urine and after the calciuretic stimulus of saline infusion.

Urinary Calcium Excretion Pattern in Preeclampsia

Aim: This study aimed to evaluate the urinary calcium excretion pattern in preeclampsia and to establish the relation between severity of preeclampsia and urinary calcium excretionMethods: This was a case-control study conducted at Paropakar Maternity and Women’s Hospital, Kathmandu from January to June 2015. There were 88 patients equally divided in each group. 24 hours urine calcium was analyzed by ortho-cresophthalin-complexone method (OCPC) and urinary proteinuria was analyzed bedside by sulphosalicylic acid. Results were analyzed using SPSS 17. P value of < 0.05 was considered as significant.Results: Preeclampsia was found to occur commonly among the nulliparous patients (59%). The patients with MAP with ≥ 110mmHg excreted less calcium in their urine in comparison to the patient with MAP < 110mmHg (73.55mg/24 hrs VS 92.79 mg/24 hr). Daily calciuria was decreased with the increase in proteinuria (91.43 mg, 76.19mg and 54.02mg in 1+, 2+ and 3+ respectively). The 24 hours urine calcium excretion in term preeclamptic patient was significantly reduced in compared to the normotensive term pregnant women (77.92 mg ± 48.61mg VS 117.66mg ±69.21 mg, p <0.001).Conclusion: Preeclamptic patients excrete significantly lower amounts of calcium in urine and it may be a marker of the severity of preeclampsia.