Risk Factors for Hypoparathyroidism Following Thyroidectomy

A Prospective Study to Assess Risk Factors for Hypoparathyroidism Following Thyroidectomy

The goal of this observational study is to identify the risk factors for post-thyroidectomy hypoparathyroidism in Estonia and to determine whether the magnesium level plays a significant role in the development of hypoparathyroidism. The main questions it aims to answer are:

• How common is post-thyroidectomy hypoparathyroidism in Estonia?
• What are the most significant risk factors for the development of post-thyroidectomy hypoparathyroidism in Estonia?
• Are magnesium levels a risk factor for the development of hypoparathyroidism? Participants will be asked to answer a questionnaire about risk factors. The study collects data on risk factors for hypoparathyroidism following thyroid surgery, including patient questionnaires and comorbidities, pre- and postoperative laboratory tests and surgery-related risk factors.

Study Overview

• Status: Recruiting
• Conditions: Post-Surgical Hypoparathyroidism

• Study Type: Observational
• Enrollment (Estimated): 300

Contacts and Locations

• Study Contact: Name: Hanna Hollman, MD; Phone Number: +37259037517; Email: hanna.hollman@ut.ee

Study Locations

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

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Probability Sample

Study Population

Patients over the age of 18 at Tartu University Hospital and East Tallinn Central Hospital who are undergoing surgery involving both lobes of the thyroid gland (thyroidectomy, "near-total" thyroidectomy, subtotal thyroidectomy, and "completed" thyroidectomy), and who provide informed consent for this.

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)
• patients who are capable of giving informed consent

Exclusion Criteria:

• patients undergoing unilateral thyroid lobectomy only
• patients with concomitant hyperparathyroidism undergoing simultaneous thyroidectomy and parathyroidectomy for a parathyroid adenoma

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
postoperative early hypoparathyroidism	Incidence of early post-thyroidectomy hypoparathyroidism, based on serum PTH levels measured on the morning of the first postoperative day	first postoperative day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Risk factor assessment of post-thyroidectomy hypoparathyroidism	Risk factors will be categorized as patient-related, disease-related, and surgery-related variables. Risk factors will be assessed using multivariable logistic regression analysis, and results will be reported as odds ratios with 95% confidence intervals. Patient-related risk factors will be assessed using a structured study-specific questionnaire (including demographic and clinical history variables) and review of electronic medical records. Disease-related risk factors will be assessed using also preoperative laboratory measurements. Surgery-related risk factors will be assessed using standardized operative reports, including variables such as extent of thyroidectomy, identification and preservation of parathyroid glands, and intraoperative findings, recorded according to institutional surgical protocols. Patient- and disease-related variables will be assessed preoperatively, while surgery-related variables will be assessed intraoperatively.	Preoperative and intraoperative periods
Serum magnesium levels as predictors of post-thyroidectomy hypoparathyroidism	Serum magnesium levels will be measured preoperatively (baseline, prior to surgery) and on postoperative day 1. The predictive value of preoperative and postoperative day 1 serum magnesium levels for early post-thyroidectomy hypoparathyroidism will be assessed using univariable and multivariable logistic regression analysis, with results reported as odds ratios and 95% confidence intervals.	Preoperative (baseline) and postoperative day 1; hypoparathyroidism assessed within 24 hours postoperatively
Postoperative permanent hypoparathyroidism	Incidence of permanent post-thyroidectomy hypoparathyroidism, defined as persistently low serum PTH levels and/or ongoing requirement for calcium and/or vitamin D supplementation at 12 months after surgery.	12 months after surgery

Collaborators and Investigators

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

Study record dates

Study Major Dates

• Study Start (Actual): October 13, 2025
• Primary Completion (Estimated): August 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 13, 2026

Study Record Updates

• Last Update Posted (Actual): May 13, 2026
• Last Update Submitted That Met QC Criteria: May 5, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: risk factors; thyroidectomy; hypoparathyroidism
• Additional Relevant MeSH Terms: Endocrine System Diseases; Parathyroid Diseases; Hypoparathyroidism
• Other Study ID Numbers: TartuUH-ETCH_403/T-13_1

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