Adding Phosphorus to Osteoporosis Drug Treatment

Study Overview
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Brief Summary
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Osteoporosis causes bones to weaken and break more easily. Calcium and phosphorus are two minerals that are essential for normal bone formation. Unfortunately, calcium salts commonly prescribed in anti-osteoporosis treatment bind phosphorus from food and restrict phosphorus available for bone building. Teriparatide is a drug that reduces the risk of fractures by increasing bone thickness and strength. Vitamin D is also necessary for strong bones and teeth. The purpose of this study is to evaluate the bone-building effectiveness of two calcium supplements, one with a source of phosphorus and one without, in combination with teriparatide and vitamin D in women with osteoporosis.

Detailed Description
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Osteoporosis is the most common type of bone disease. Calcium supplements normally used in anti-osteoporosis treatment are calcium salts of carbonate or citrate; however, these salts bind phosphorus from food in the intestine and restrict phosphorus available for bone building. This study will evaluate the efficacy of adding calcium phosphate to a regimen of teriparatide and vitamin D in increasing bone mineral density in women with osteoporosis. It is hypothesized that the group taking the phosphate-containing calcium supplement will have greater gains in bone mineral density (BMD) during the course of the study than the group not receiving phosphate. All participants will receive teriparatide and vitamin D during the course of the 12-month study. Participants will be randomly assigned to one of two groups. One group will receive calcium phosphate and the other will receive calcium carbonate. BMD will be measured at spine and hip at baseline and at 3, 6, and 12 months of treatment.

Official Title
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Bone Sparing by Calcium Salts With and Without Extra Phosphorus

Conditions
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Osteoporosis, Osteopenia

Intervention / Treatment
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* Drug: Calcium carbonate
* Drug: Calcium Phosphate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Bone mineral density (BMD) T-score less than -1.0 One or more vertebral fractures Serum creatinine less than 1.3 mg/dL Serum phosphorus less than 3.6 mg/dL Daily phosphorus intake below NHANES-III median Body mass index (BMI) less than 30 kg/m2 Exclusion Criteria: Paget's disease or history of osteosarcoma Systemic corticosteroid therapy Hyperparathyroidism Recent history of kidney stone Anticonvulsant therapy known to alter vitamin D metabolism Radiation therapy to bone

Ages Eligible for Study
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Minimum Age: 60 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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Female

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: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Calcium Phosphate Treatment Group<br>Participants will receive teriparatide and vitamin D during the course of the 12-month study. They will also receive calcium phosphate. | Drug: Calcium Phosphate<br>* Participants will receive teriparatide and vitamin D during the course of the 12-month study. They will also receive calcium phosphate.<br>|
| Active Comparator: Calcium Carbonate Treatment Group<br>Participants will receive teriparatide and vitamin D during the course of the 12-month study. They will also receive calcium carbonate. | Drug: Calcium carbonate<br>* Participants will receive teriparatide and vitamin D during the course of the 12-month study. They will also receive calcium carbonate.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lumbar Spine and Hip BMD, Measured as Grams Per Square Centimeter. | Bone mineral density (BMD, measured by dual X-ray absorptiometry - DEXA) measured at several intervals during the study. BMD measured as grams per square centimeter (g/cm2). | Measured at Baseline | 
| Bone Mineral Density (BMD) Under Treatment With an Anabolic Agent (Teriparatide). | The principle outcome measure was change in bone mineral density (BMD) under treatment with an anabolic agent (teriparatide). | 12 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change From Baseline in Serum Phosphorus, Serum Creatinine, Serum Calcium at 12 Months |  | Measured at baseline and 12 months | 
| Change From Baseline in Urinary Calcium to Creatinine Ratio, Urinary Phosphorus to Creatinine Ratio at 12 Months |  | Measured at baseline and 12 months | 
| Change From Baseline in Urinary N-telopeptide at 12 Months |  | Measured at baseline and 12 months | 
| Change From Baseline in Urinary Hydroxyproline to Creatinine Ratio at 12 Months |  | Measured at baseline and 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Bone Mineral Density, Calcium