Serum Calcium to Phosphorous (Ca/P) Ratio in the Diagnosis of Ca-P Metabolism Disorders: a Multicentre Study

Study Overview
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Brief Summary
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Primary hyperparathyroidism (PHPT) and Hypoparathyroidism (HP) are two of the most frequent disorder of Calcium-Phosphorus (Ca-P) metabolism. The Ca/P ratio is an accurate tool to differentiate patients with PHPT from healthy subjects, according to a previous single-centre study. The reliability of this index is based on the fact that serum Ca and P are inversely related together either in healthy subjects or in patients with PHPT and HP.

Detailed Description
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The aim of this study is to investigate the accuracy and diagnostic value of Ca/P ratio in the diagnosis of primary hyperparathyroidism and hypoparathyroidism. The definition of a valid cut-off of serum Ca/P ratio for patients with these disorders will be of help especially in those patients with apparently normal biochemical profile, but suggestive for primary hyperparathyroidism and hypoparathyroidism.

Official Title
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Serum Calcium to Phosphorous (Ca/P) Ratio in the Diagnosis of Ca-P Metabolism Disorders: a Multicentre Study

Conditions
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Phosphorus and Calcium Disorders, Parathyroid Diseases, Hyperparathyroidism, Hypoparathyroidism

Intervention / Treatment
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* Other: No intervention is provided


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients with diagnosis of primary hyperparathyroidism patients with diagnosis of hypoparathyroidism subjects with normal Calcium-Phosphorus metabolism Exclusion Criteria for both cases and controls will be: age younger than 18 or older than 90 years severe renal and liver diseases (i.e. glomerular filtration rate (GFR) <30 ml/min) hyperparathyroidism secondary to Vitamin D deficiency active metabolic bone disease (e.g. Paget's disease of the bone, osteomalacia, rickets, etc) any type of cancer malnutrition severe obesity (BMI > 40 kg/m2) a history of gastrointestinal malabsorption sarcoidosis hypercortisolism diabetes insipidus hyperthyroidism pseudohypoparathyroidism familial hypocalciuric hypercalcemia (FHH) treatment with steroids, active forms of vitamin D (calcitriol, ergocalciferol, etc), thiazides, phosphate binders, lithium, cinacalcet, bisphosphonates, and denosumab.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 90 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with hyperparathyroidism<br>Patients aged between 18-90 years old with primary hyperparathyroidism. No intervention is provided. | Other: No intervention is provided<br>* No intervention is provided<br>|
| Patients with hypoparathyroidism<br>Patients aged between 18-90 years old with diagnosed hypoparathyroidism. No intervention is provided. . | Other: No intervention is provided<br>* No intervention is provided<br>|
| Control group<br>Patients that underwent biochemical examination by primary care physician or by endocrinologist in order to assess their calcium-phosphorus metabolism state with normal results. No intervention is provided. | Other: No intervention is provided<br>* No intervention is provided<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum Calcium to Phosphorus ratio | Calculated formula (serum calcium to serum phosphorus ratio) | Assessed only once at the diagnosis (from January 2005 to January 2018) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Serum Calcium | From blood sample - Unit of measurement: mg/dl | Assessed only once at the diagnosis (from January 2005 to January 2018) | 
| Serum Phosphorus | From blood sample - Unit of measurement: mg/dl | Assessed only once at the diagnosis (from January 2005 to January 2018) | 
| Serum Parathormone | From blood sample - Unit of measurement: pg/ml | Assessed only once at the diagnosis (from January 2005 to January 2018) |