Optimal HCTZ Cessation for Diagnosis of Hyperparathyroidism

Optimal Hydrochlorothiazide Cessation in 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.

Study Overview

• Status: Completed
• Conditions: Hyperparathyroidism
• Intervention / Treatment: Procedure: HCTZ cessation

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 2
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Missouri
    • Columbia, Missouri, United States, 65212
      • University of Missouri

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

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

Exclusion Criteria:

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: HCTZ cessation; Patients will stop taking HCTZ for 3 months while submitting serial blood and 24 hour urine samples	Procedure: HCTZ cessation; Patients will stop taking their HCTZ for 3 months

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of days for Calcium/Creatinine Clearance to normalize after stopping HCTZ	Determination of the HCTZ cessation window	2-3 years

Collaborators and Investigators

• Sponsor: University of Missouri-Columbia
• Investigators: Principal Investigator: Robert P Zitsch, MD, University of Missouri-Columbia

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2015
• Primary Completion (Actual): September 13, 2017
• Study Completion (Actual): September 13, 2017

Study Registration Dates

• First Submitted: October 27, 2015
• First Submitted That Met QC Criteria: October 28, 2015
• First Posted (Estimate): October 29, 2015

Study Record Updates

• Last Update Posted (Actual): January 8, 2018
• Last Update Submitted That Met QC Criteria: January 4, 2018
• Last Verified: January 1, 2018

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Endocrine System Diseases; Parathyroid Diseases; Hyperparathyroidism
• Other Study ID Numbers: 1213821

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared.