Calcium Replacement Therapy in Postoperative Hypoparathyroidism

A Pilot Study of Calcium Replacement Therapy in Postoperative Hypoparathyroidism

The goal of this clinical trial is to evaluate whether a lower-dose calcium replacement therapy is non-inferior to a higher-dose regimen in preventing symptomatic hypoparathyroidism in patients following thyroidectomy. The hypothesis is:

• lower-dose calcium replacement therapy is non-inferior to higher-dose therapy in preventing symptomatic hypoparathyroidism during the first two postoperative weeks

Researchers will compare patients receiving a lower-dose calcium replacement regimen with those receiving a higher-dose regimen to assess whether the lower dose is not associated with a higher incidence of symptomatic hypoparathyroidism.

Patients who develop post-thyroidectomy hypoparathyroidism are divided into groups for calcium replacement therapy. If they are asymptomatic, they will be scheduled for a follow-up visit at two weeks after surgery. During the follow-up visit, calcium metabolism will be evaluated, and treatment adjusted if necessary.

Study Overview

• Status: Recruiting
• Conditions: Post-Thyroidectomy Hypoparathyroidism Treatment
• Intervention / Treatment: Drug: Calcium carbonate 1250 mg (500 mg elemental calcium) twice a day; Drug: Calcium carbonate 1250 mg (500 mg elemental calcium) 4 times a day

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Hanna Hollman; Phone Number: +37259037517; Email: hanna.hollman@ut.ee
• Study Contact Backup: Name: Ceith Nikkolo; Phone Number: +372 53318092

Study Locations

• Estonia
  • Tartu, Estonia
    • Recruiting
    • Tartu University Hospital
    • Contact: Ceith Nikkolo, PhD; Phone Number: +372 53319082; Email: ceith.nikkolo@kliinikum.ee
  • Other
    • Tallinn, Other, Estonia, 11914
      • Recruiting
      • East Tallinn Central Hospital
      • Contact: Hanna Hollman, MD; Phone Number: + 372 59037517; Email: hanna.hollman@itk.ee

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• patients over the age of 18 undergoing surgery involving both lobes of the thyroid gland (thyroidectomy, "near-total" thyroidectomy, subtotal thyroidectomy, and "completed" thyroidectomy)
• Based on the first post-operative day analysis, PTH levels are below the normal range (in our hospitals 1.8-7.8 pmol/l), but not so low (below 1.06 pmol/L) as to require calcium replacement therapy with calcitriol (rocaltrol)

Exclusion Criteria:

• previously diagnosed osteoporosis; the patient is already taking calcium and vitamin D supplements prior to thyroid surgery
• renal insufficiency (eGFR < 30)
• patients with concomitant hyperparathyroidism undergoing simultaneous thyroidectomy and parathyroidectomy for a parathyroid adenoma

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Lower dose calcium replacement; calcium carbonate 1250 mg x 2	Drug: Calcium carbonate 1250 mg (500 mg elemental calcium) twice a day; One study group takes calcium carbonate 1250 mg (500 mg elemental calcium) twice a day (at lunchtime and in the evening)
Active Comparator: Higher dose calcium replacement; calcium carbonate 1250 mg x 4	Drug: Calcium carbonate 1250 mg (500 mg elemental calcium) 4 times a day; The second study group takes 1250 mg of calcium carbonate (500 mg of elemental calcium) four times a day (starting at noon, at approximately 4-hour intervals: at noon, in the early afternoon, in the evening, and before bedtime). This dosage regimen is prescribed because 500 mg of calcium can be absorbed at a time.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Occurence of symptomatic hypoparathyroidism	Occurrence of symptomatic hypoparathyroidism within 14 days postoperatively	2 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Serum calcium levels at 2 week follow-up	Comparison of serum calcium levels at the 2-week follow-up between lower- and higher-dose calcium replacement groups.	2 weeks
Duration and permanence of hypoparathyroidism	Assessment of whether postoperative hypoparathyroidism resolves (transient) or persists (permanent) during follow-up.	Up to 12 months postoperatively
Serum parathyroid hormone (PTH) levels at 2 week follow-up	Comparison of serum parathyroid hormone (PTH) levels at the 2-week follow-up between lower- and higher-dose calcium replacement groups.	2 weeks

Collaborators and Investigators

• Sponsor: Tartu University Hospital
• Collaborators: East Tallinn Central Hospital

Study record dates

Study Major Dates

• Study Start (Actual): November 18, 2025
• Primary Completion (Estimated): October 1, 2027
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: April 21, 2026
• First Submitted That Met QC Criteria: May 5, 2026
• First Posted (Actual): May 11, 2026

Study Record Updates

• Last Update Posted (Actual): May 11, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: thyroidectomy; postoperative hypoparathyroidism; calcium replacement therapy
• Additional Relevant MeSH Terms: Biological Factors; Inorganic Chemicals; Elements; Metals; Minerals; Blood Coagulation Factors; Calcium Compounds; Metals, Alkaline Earth; Carbon Compounds, Inorganic; Carbonates; Carbonic Acid; Calcium; Calcium Carbonate
• Other Study ID Numbers: TartuUH-ETCH_403/T-13_2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No