Investigation of the Optimal Calcium Supplement Following Roux-en-Y Gastric Bypass

Study Overview
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Brief Summary
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This study investigates whether calcium citrate or calcium carbonate are the optimal supplement to treat secondary hyperparathyroidism following Roux-en-Y gastric bypass operation. Half of the participants will be randomized to receive calcium citrate, while the other half will receive calcium carbonate. The study will be double blinded.

Official Title
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Investigation of the Optimal Calcium Supplement Following Roux-en-Y Gastric Bypass in Order to Treat Secondary Hyperparathyroidism: A Clinical Randomized Trial

Conditions
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Roux-en-Y Gastric Bypass, Hyperparathyroidism, Secondary

Intervention / Treatment
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* Dietary Supplement: Calcium Carbonate
* Dietary Supplement: Calcium Citrate
* Dietary Supplement: Placebo
* Procedure: Roux-en-Y gastric bypass


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Roux-en-Y gastric bypass operation ≥12 months ago Parathyroid hormone > 6.9 pmol/l Vitamin D > 50 nmol/l P-Calcium [1.18-1.32] mmol/l Exclusion Criteria: Liver disease Renal disease Hypercalcemia Untreated thyroid disease Parathyroid disease except secondary hyperparathyroidism Use of diuretics, bisphosphonates, calcitonin, teriparatide, oral corticosteroids, anabolic steroids, calcimimetics, lithium, strontium, denosumab or anticonvulsants within 1 year of inclusion abusing alcohol

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Calcium Carbonate<br>1 tablet Unikalk Forte + 1 placebo tablet by mouth three times daily equal to 1200 mg elementary calcium and 57 µg Vitamin D3 | Dietary Supplement: Calcium Carbonate<br> <br> * Other names: Unikalk Forte;Dietary Supplement: Placebo<br>* Tablet manufactured to mimic a calcium carbonate tablet<br>Procedure: Roux-en-Y gastric bypass<br>* Roux-en-Y gastric bypass surgery at least 12 months before study inclusion<br>|
| Experimental: Calcium Citrate<br>2 tablets Unikalk Citrat by mouth three times daily equal to 1200 mg elementary calcium and 60 µg Vitamin D3 | Dietary Supplement: Calcium Citrate<br> <br> * Other names: Unikalk Citrat;Procedure: Roux-en-Y gastric bypass<br>* Roux-en-Y gastric bypass surgery at least 12 months before study inclusion<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Parathyroid Hormone |  | Change from baseline at 6 weeks and 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Se-ion-calcium |  | Change from baseline at 6 weeks and 12 weeks | 
| P-magnesium |  | Change from baseline at 6 weeks and 12 weeks | 
| P-phosphate |  | Change from baseline at 6 weeks and 12 weeks | 
| P-25-OH-vitamin D |  | Change from baseline at 6 weeks and 12 weeks | 
| P-calcitriol |  | Change from baseline at 6 weeks and 12 weeks | 
| P-24,25-(OH)2-vitamin D |  | Change from baseline at 6 weeks and 12 weeks | 
| Vitamin D binding protein |  | Change from baseline at 6 weeks and 12 weeks | 
| Procollagen type 1 N-terminal propeptide (P1NP) |  | Change from baseline at 6 weeks and 12 weeks | 
| P-bone specific alkaline phosphatase |  | Change from baseline at 6 weeks and 12 weeks | 
| Cross-linked C-telopeptide (CTX) |  | Change from baseline at 6 weeks and 12 weeks | 
| 24h U-calcium |  | Change from baseline at 12 weeks | 
| 24h U-phosphate |  | Change from baseline at 12 weeks |