Optimal HCTZ Cessation for Diagnosis of Hyperparathyroidism

Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia in the ambulatory setting. PHPT may be cured with surgery and indications for intervention have been defined and include urinary calcium/creatinine clearance. Hydrochlorothiazide (HCTZ), the most commonly prescribed medication for hypertension, reduces urinary calcium excretion and confounds urinary testing. As a result, it is universally recommended that thiazide diuretics be stopped in advance of urinary testing. To date, no studies are available to provide evidence-based guidance as to how long HCTZ must be held for urinary calcium excretion to return to steady state in PHPT. The objective of this study is to serially calculate urinary calcium/creatinine clearance ration in patients with suspected PHPT while holding HCTZ to determine the minimum duration of medication cessation necessary for urinary calcium clearance to reach steady state.

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Key information

Conditions

Hyperparathyroidism Endocrine System Diseases Parathyroid Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Missouri

Columbia, Missouri, 65212, United States

About this study

In this study, adult patients will submit serum and 24 hour urine samples prior to HCTZ cessation and at the following intervals after cessation: 4-6 days, 14-16 days, 28-30 days, adn 90-92 days. To minimize confounding variable, patients will take supplemental Vitamin D and Calcium, monitor their daily calcium intake, and monitor blood pressure weekly. Alternative, non-diuretic, antihypertensive medication(s) may be prescribed at the discretion of the enrolling provider.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Elevated calcium on at least two separate draws with coexistent elevated parathyroid hormone (PTH) on at least one occasion.
Taking Hydrochlorothiazide for hypertension
Following a "wash period", patients must have a normal range 25-hydroxy Vitamin D level, thyroid stimulation hormone (TSH) and serum magnesium levels.
Controlled blood pressure
Willingness to comply with serial sampling
English as the primary language
Adults 18 years and older

Exclusion criteria

Unable to cease Hydrochlorothiazide for any reason
Congestive heart failure
Renal insufficiency (GFR <60)
Cardiovascular event in the last 3 months - include myocardial infarction, new onset atrial fibrillation, and new onset bundle branch block
Take lithium or other diuretic medication in last 3 months
Positive family history of familial hypocalciuric hypercalcemia (FHH)

Treatment and study plan

HCTZ cessation

Procedure

Patients will stop taking their HCTZ for 3 months

Primary outcomes

Number of days for Calcium/Creatinine Clearance to normalize after stopping HCTZ

Time frame: 2-3 years

Determination of the HCTZ cessation window

Sponsors and collaborators

Lead sponsor

University of Missouri-Columbia

Other

Registry information

Official study title

Optimal Hydrochlorothiazide Cessation in Diagnosis of Hyperparathyroidism

Important dates

Study start: 2015
Primary completion: 2017
Study completion: 2017
First posted: Oct 29, 2015
Registry last updated: Jan 8, 2018

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Published trials that share one or more normalized conditions with this study.

Completed