Clinical trial NCT03603444: Reliability of Serum Calcium to Phosphorus (Ca/P) Ratio as an Accurate and Inexpensive Tool to Define Disorders of Ca-P Metabolism
Official title: Serum Calcium to Phosphorus (Ca/P) Ratio to Define Disorders of Ca-P Metabolism
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Phosphorus and Calcium Disorders
Lead sponsor: Azienda Ospedaliero-Universitaria di Modena
Sponsor class: OTHER
First posted: 2018-07-27
Enrollment: 606
Sex: ALL
Minimum age (years): 18
Maximum age (years): 90
Standard ages: ADULT
OLDER_ADULT
Observational model: CASE_CONTROL
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Serum Calcium to Phosphorus ratio will be compared among patients with different disorders of calcium-phosphorus metabolism (primary hyperparathyroidism and hypophosphoremia) and controls.

Brief summary: BACKGROUND: Primary hyperparathyroidism (PHPT) is the third most common endocrine disorder. The Ca/P ratio is an accurate tool to differentiate patients with PHPT (\>3.5 if Ca and P are expressed in mg/dl) from healthy subjects. The reliability of this index is based on the fact that serum Ca and P are inversely related together. However, other disorders of the Ca-P metabolism, such as hypophosphoremia (HypoP) not related to PHPT, might also impair the Ca/P ratio.

OBJECTIVE: To validate the accuracy of Ca/P ratio in the diagnosis of Ca-P metabolism disorders, including also patients with documented HypoP not related to PHPT.

METHODS: A single-center, retrospective, case-control study will be carried out.

Biochemical measurements will include parathormone (PTH), vitamin D, serum Ca and P, serum albumin and creatinine.


Eligibility criteria: Inclusion Criteria:

* patients with diagnosis of primary hyperparathyroidism
* HIV-infected patients with reduced phosphorus but normal calcium
* 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.

Primary outcomes:
measure: Serum Calcium to Phosphorus ratio
timeFrame: Assessed only once at the diagnosis (from January 2005 to January 2018)
Secondary outcomes:
measure: Serum Calcium
timeFrame: Assessed only once at the diagnosis (from January 2005 to January 2018)
measure: Serum Phosphorus
timeFrame: Assessed only once at the diagnosis (from January 2005 to January 2018)
measure: Serum Parathormone
timeFrame: Assessed only once at the diagnosis (from January 2005 to January 2018)
Other outcomes:
Locations:
city: Modena
country: Italy
facility: Azienda Ospedaliero - Universitaria di Modena
Study officials:
References: