Postoperative Hypocalcemia After Thyroidectomy

A Ten-Year Cohort Study of Clinical and Surgical Predictors for Hypocalcemia Post-Thyroidectomy

This retrospective cohort study investigates predictors of postoperative hypocalcemia following thyroidectomy procedures at Minia University Hospital over a 10-year period (2014-2024). Postthyroidectomy hypocalcemia is one of the most common complications of thyroid surgery, affecting 20-50% of patients. The study aims to identify demographic, clinical, laboratory, and surgical factors associated with the development of both transient and permanent hypocalcemia. Results will inform risk stratification, patient counseling, and perioperative management strategies.

Study Overview

• Status: Recruiting
• Conditions: Postoperative Complications; Hypocalcemia; Thyroid Cancer; Thyroid Nodule; Thyroid Dysfunction

Detailed Description

Hypocalcemia is a frequent complication following thyroidectomy, resulting from inadvertent parathyroid gland injury, removal, or devascularization. While most cases resolve within 6 months (transient hypocalcemia),permanent hypocalcemia occurs in 1-3% of patients and requires lifelong calcium and vitamin D supplementation, significantly impacting quality of life.

This single-center retrospective study will systematically review medical records of all patients who underwent thyroidectomy (total, subtotal, or completion) at Minia University Hospital between January 1, 2014, andDecember 31, 2024. The primary objective is to identify independent predictors of postoperative hypocalcemia using multiple logistic regression analysis.

Data extraction will include:

Demographics: age, gender, BMI Clinical factors: indication for surgery, thyroid disease type, presence of Graves' disease, substernal extension Preoperative laboratory values: calcium, vitamin D, PTH, thyroid function tests Surgical details: extent of thyroidectomy, central/lateral lymph node dissection, surgeon experience,operative time, parathyroid gland identification and autotransplantation Postoperative data: calcium levels (24h, 48h, 1 week, 6 weeks, 3 months, 6 months), PTH levels,supplementation requirements Pathology: thyroid weight, presence of parathyroid tissue in specimen, thyroiditis, malignancy The study will employ robust statistical methods including univariate analysis to screen potential predictors and multiple logistic regression to identify independent risk factors. A clinical risk prediction score will be developed and internally validated using split-sample methodology. Subgroup analyses will examine differences between transient and permanent hypocalcemia and stratify results by extent of surgery and surgeon experience.

Target sample size of 500-600 patients was calculated using G*Power to ensure adequate statistical power(>80%) .

Findings will contribute to evidence-based perioperative protocols, improved patient selection for outpatient thyroidectomy, tailored monitoring strategies, and informed decision-making regarding prophylactic calcium supplementation.

• Study Type: Observational
• Enrollment (Estimated): 600

Contacts and Locations

• Study Contact: Name: Saleh K Saleh, MD; Phone Number: +2 01201765401; Email: salehkhairy@mu.edu.eg

Study Locations

• Egypt
  • Minya Governorate
    • Minya, Minya Governorate, Egypt, 61519
      • Recruiting
      • Minia University Hospital
      • Contact: Saleh K Saleh, MD; Phone Number: +2 01201765401; Email: salehkhairy@mu.edu.eg
      • Sub-Investigator: Rabeh K Saleh, MD
      • Contact: Email: salehkhairy@mu.edu.eg

Participation Criteria

Eligibility Criteria

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

• Sampling Method: Non-Probability Sample

Study Population

This retrospective cohort study will include adult patients (aged 18 years and older) who underwent a thyroidectomy procedure at Minia University Hospital, a tertiary care centre in Egypt, between January 1, 2014, and December 31, 2024. The target population consists of approximately 600 consecutive patients who meet the eligibility criteria. This includes patients with available medical records containing complete surgical and postoperative data, documented postoperative serum calcium levels, and a minimum of 6 months of follow-up or a documented outcome status. Patients will be excluded if they have preoperative hypocalcemia, pre-existing parathyroid disorders, chronic kidney disease (Stage 3 or higher), or other conditions that significantly affect calcium metabolism. The study population represents a consecutive sample of all patients meeting these criteria over the 10-year study period at this single academic center.

Description

Inclusion Criteria:

• Adult patients aged 18 years or older at time of surgery
• Underwent thyroidectomy at Minia University Hospital
• Availability of medical records with complete surgical and postoperative data
• Documented serum calcium levels measured postoperatively
• Minimum follow-up of 6 months postoperatively or documented outcome status

Exclusion Criteria:

• Age less than 18 years at time of surgery
• Preoperative hypocalcemia (serum calcium <8.0 mg/dL or ionized calcium <1.0 mmol/L)
• Pre-existing parathyroid disorders (primary hyperparathyroidism, hypoparathyroidism, secondary or tertiary hyperparathyroidism)
• Chronic kidney disease Stage 3 or higher (estimated glomerular filtration rate <60 mL/min/1.73m²)
• Malabsorption syndromes affecting calcium metabolism (celiac disease, inflammatory bowel disease,short bowel syndrome)
• Concurrent planned parathyroidectomy
• History of neck irradiation
• Chronic use of medications significantly affecting calcium metabolism (bisphosphonates, denosumab,cinacalcet, chronic corticosteroids)
• Incomplete medical records lacking essential data including surgical details, postoperative calcium levels,or follow-up data
• Patients lost to follow-up before 6-month endpoint without documented outcome status

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of Postoperative Hypocalcemia	Development of hypocalcemia defined as: Serum total calcium <8.0 mg/dL (2.0 mmol/L) OR Ionized calcium <1.0 mmol/L OR Symptomatic hypocalcemia (perioral numbness, paresthesias, carpopedal spasm, positive Chvostek's orTrousseau's sign) requiring calcium supplementation Measured at: 24 hours, 48 hours, 1 week, 6 weeks, 3 months, and 6 months postoperatively	Within 6 months post-surgery

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hospital Length of Stay	Duration of hospitalization in days following thyroidectomy, measured from date of surgery to date of hospital discharge	From surgery to discharge, typically 2-5 days
Calcium and Vitamin D Supplementation Requirement	Need for oral calcium supplementation (yes/no and total daily dose in mg) Need for vitamin D supplementation (yes/no and total daily dose in IU) Duration of supplementation (days/weeks) Need for intravenous calcium administration (yes/no)	Up to 6 months post-surgery
Emergency Department Visits for Hypocalcemia	Unplanned emergency department visits related to symptoms of hypocalcemia or complications of calcium/vitamin D therapy	Within 30 days post-discharge
Hospital Readmission Related to Hypocalcemia	Unplanned hospital readmission related to symptomatic hypocalcemia or its complications	Within 30 days post-discharge
Postoperative Parathyroid Hormone (PTH) Level	Serum intact parathyroid hormone level measured within 24 hours postoperatively (pg/mL), used as predictor of sustained hypocalcemia	24 hours post-surgery
Nadir Calcium Level	Lowest serum calcium level (total or ionized) recorded during initial hospitalization or within first week postoperatively	Within 7 days post-surgery
Time to Calcium Normalization	Duration in days from surgery to sustained normalization of serum calcium levels without supplementation (for those who develop hypocalcemia)	Up to 6 months post-surgery
Incidence of Transient Hypocalcemia	Hypocalcemia that resolves within 6 months of surgery without need for continued calcium and/or vitamin D supplementation beyond 6-month follow-up	Up to 6 months post-surgery
Incidence of Permanent Hypocalcemia	Hypocalcemia requiring ongoing calcium and/or vitamin D supplementation persisting beyond 6months postoperatively, indicating permanent hypoparathyroidism	6 months post-surgery
Incidence of Symptomatic Hypocalcemia	Clinical manifestations of hypocalcemia including: Neuromuscular irritability (perioral tingling, paresthesias) Tetany or carpopedal spasm Positive Chvostek's sign (facial nerve twitching) Positive Trousseau's sign (carpal spasm with blood pressure cuff inflation) Seizures (rare) Cardiac manifestations: prolonged QT interval, arrhythmias (rare)	Within 2 weeks post-surgery

Collaborators and Investigators

• Sponsor: Minia University
• Investigators: Principal Investigator: Saleh K Saleh, MD, Minia University

Publications and helpful links

General Publications

• Edafe O, Antakia R, Laskar N, Uttley L, Balasubramanian SP. Systematic review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia. Br J Surg. 2014 Mar;101(4):307-20. doi: 10.1002/bjs.9384. Epub 2014 Jan 9.
• Thomusch O, Machens A, Sekulla C, Ukkat J, Brauckhoff M, Dralle H. The impact of surgical technique on postoperative hypoparathyroidism in bilateral thyroid surgery: a multivariate analysis of 5846 consecutive patients. Surgery. 2003 Feb;133(2):180-5. doi: 10.1067/msy.2003.61.
• Lorente-Poch L, Sancho JJ, Ruiz S, Sitges-Serra A. Importance of in situ preservation of parathyroid glands during total thyroidectomy. Br J Surg. 2015 Mar;102(4):359-67. doi: 10.1002/bjs.9676. Epub 2015 Jan 20.

Study record dates

Study Major Dates

• Study Start (Actual): March 4, 2026
• Primary Completion (Estimated): May 1, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: February 17, 2026
• First Submitted That Met QC Criteria: February 17, 2026
• First Posted (Actual): February 23, 2026

Study Record Updates

• Last Update Posted (Actual): March 6, 2026
• Last Update Submitted That Met QC Criteria: March 4, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Thyroidectomy; Hypoparathyroidism; Total thyroidectomy; Postoperative hypocalcemia; Parathyroid gland injury
• Additional Relevant MeSH Terms: Endocrine System Diseases; Pathologic Processes; Neoplasms by Site; Neoplasms; Metabolic Diseases; Endocrine Gland Neoplasms; Head and Neck Neoplasms; Water-Electrolyte Imbalance; Parathyroid Diseases; Thyroid Diseases; Calcium Metabolism Disorders; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Thyroid Nodule; Hypoparathyroidism; Thyroid Neoplasms; Postoperative Complications; Hypocalcemia
• Other Study ID Numbers: 1878/02/2026

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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