Parathyroidectomy After Kidney Transplantation (Para-KiT)

February 16, 2026 updated by: Aarhus University Hospital

Subtotal Parathyroidectomy for the Treatment of Persistent Hyperparathyroidism After Kidney Transplantation

This study aims to clarify whether surgical treatment of persistent hyperparathyroidism after kidney transplantation offers clinically meaningful benefits compared with a conservative treatment strategy.

Kidney transplant recipients (>6 mo after transplantation) with persistent hyperparathyroidism (elevated PTH and either hypercalcemia or hypophosphatemia) will be randomized in a 1:1 ratio to either subtotal parathyroidectomy or conservative management according to standard clinical practice. The study is conducted as an open-label, randomized controlled pilot trial with a 12-month follow-up period.

Outcomes include bone density, physical function, quality of life and symptom burden.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Persistent hyperparathyroidism is a frequent complication after kidney transplantation. Despite improved kidney function, many transplant recipients continue to have elevated parathyroid hormone (PTH) levels, often accompanied by hypercalcemia and/or hypophosphatemia. These disturbances are associated with adverse effects on skeletal health and have been linked to increased risk of fractures, graft dysfunction, and mortality.

Currently, there are no evidence-based guidelines for the optimal management of persistent hyperparathyroidism after kidney transplantation. Conservative management with biochemical monitoring and supportive medical therapy is commonly used, while surgical parathyroidectomy is typically reserved for patients with severe biochemical abnormalities. Although parathyroidectomy is effective in normalizing PTH, calcium, and phosphate levels, and observational data suggest beneficial effects on bone mineral density, randomized controlled trials comparing surgical and conservative management strategies in this population are lacking.

The purpose of this study is to evaluate the safety and efficacy of subtotal parathyroidectomy compared with conservative management in kidney transplant recipients with persistent hyperparathyroidism.

The study is conducted as an open-label, randomized controlled pilot trial with a 12-month follow-up period. Kidney transplant recipients (>6 mo after transplantation, no upper limit) with persistent hyperparathyroidism (elevated PTH and either hypercalcemia or hypophosphatemia) will be randomized in a 1:1 ratio to either subtotal parathyroidectomy or conservative management according to standard clinical practice. Controls will be treated with calcium, vitamin D and phosphate supplements as needed. Calcimimetic use is not mandated for controls, but can be utilized at the discretion of the treating physician.

The primary objective is to assess the change in bone mineral density at the total hip after 12 months.

Secondary objectives include evaluation of changes in mineral metabolism parameters, bone turnover markers, bone microarchitecture, physical function and muscle strength, quality of life and symptom burden, kidney graft function, and safety outcomes.

Study Type

Interventional

Enrollment (Estimated)

85

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

  • Name: Amal Derai, MD
  • Phone Number: +45 51 36 03 80
  • Email: amader@rm.dk

Study Locations

  • Denmark
    • Central Jutland
      • Aarhus, Central Jutland, Denmark, 8200
        • Recruiting
        • Departement of Nephrology, Aarhus University hospital
        • Contact:
        • Contact:
          • Amal Derai, MD, PhD
          • Phone Number: +45 51 36 03 80
          • Email: amader@rm.dk

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age > 18 years and legally competent and able to understand spoken and written Danish
  • Kidney transplantation ≥ 6 months prior (no upper limit of time after transplantation)
  • Stable kidney graft function, defined as estimated GFR ≥ 30 ml/min/1.73m3
  • On two consecutive biochemical measurements: PTH ≥1.5 times normal limit of assay and ionized calcium ≥1.35 mmol/L or albumin-corrected calcium ≥2.70 mmol/L or phosphate ≤0.50 mmol/L

Exclusion Criteria:

  • Inability to provide written, informed consent
  • Current anti-resorptive therapy (bisphosphonate, denosumab)
  • Current bone anabolic therapy (teriparatide, romosozumab)
  • Previous surgical parathyroidectomy
  • Not considered fit for surgery (including pregnancy)
  • Ionized calcium ≥1.50 mmol/L or albumin-corrected calcium ≥3.00 mmol/L despite discontinuation of calcium supplements.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Surgery group
Participants assigned to this arm will undergo subtotal parathyroidectomy performed according to standard surgical practice. The procedure involves removal of the majority of parathyroid tissue with preservation of a small remnant. Intraoperative parathyroid hormone (PTH) measurements will be used to guide the extent of resection, in accordance with standard surgical principles. Surgery will be performed by experienced ear, nose and throat (ENT) surgeons. Participants will receive standard perioperative care and postoperative follow-up.
Procedure: Subtotal Parathyroidectomy
Subtotal parathyroidectomy performed according to standard surgical practice. The procedure involves removal of the majority of parathyroid tissue with preservation of a small remnant. Intraoperative parathyroid hormone (PTH) measurements are used to guide the extent of resection. Standard perioperative care and postoperative follow-up are provided.
Active Comparator: Control group
Participants assigned to this arm will receive conservative management according to standard clinical practice. This includes regular clinical follow-up and biochemical monitoring of calcium, phosphate, and parathyroid hormone levels. Medical treatment, such as calcium or vitamin D supplementation and/or calcimimetic therapy, may be initiated or adjusted at the discretion of the treating physician. No parathyroid surgery will be performed during the 12-month study period.
Other: Conservative Management
Conservative management according to standard clinical practice, including regular clinical follow-up and biochemical monitoring of calcium, phosphate, and parathyroid hormone levels. Medical treatment, such as calcium or vitamin D supplementation and/or calcimimetic therapy, may be initiated or adjusted based on clinical judgment.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in bone mineral density (BMD) at the total hip
Time Frame: From baseline to end of study at 12 months
Bone mineral density (BMD) at the total hip will be measured using dual-energy X-ray absorptiometry (DXA) according to standardized procedures. Measurements will be performed at baseline and after 12 months. The primary outcome is the change in bone mineral density from baseline to 12 months.
From baseline to end of study at 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Changes in cortical and trabecular bone microarchitecture
Time Frame: From baseline to end of study at 12 months
Bone microarchitecture will be assessed using high-resolution peripheral quantitative computed tomography (HR-pQCT) at baseline and after 12 months. Parameters will include measures of trabecular and cortical bone structure. The outcome is the change in these parameters from baseline to 12 months.
From baseline to end of study at 12 months
Mineral metabolism: Change in plasma parathyroid hormone (PTH)
Time Frame: From baseline to end of study at 12 months
Plasma plasma parathyroid hormone PTH [pmol/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
From baseline to end of study at 12 months
Mineral metabolism: Changes in serum ionized calcium and phosphate
Time Frame: From baseline to end of study at 12 months
Serum ionized calcium [mmol/L] and phosphate [mmol/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
From baseline to end of study at 12 months
Mineral metabolism: Change in plasma fibroblast growth factor 23 (FGF23)
Time Frame: From baseline to end of study at 12 months
Plasma fibroblast growth factor 23 FGF23 [ng/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months
From baseline to end of study at 12 months
Bone turnover marker: Change in bone-specific alkaline phosphatase (BALP)
Time Frame: From baseline to end of study at 12 months
Bone-specific alkaline phosphataseBALP [µg/l] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
From baseline to end of study at 12 months
Bone turnover marker: Change in plasma C-terminal crosslinks (CTX)
Time Frame: From baseline to end of study at 12 months
CTX [µg/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
From baseline to end of study at 12 months
Bone turnover marker: Change in plasma procollagen type I N-terminal propeptide (PINP, intact and total forms)
Time Frame: From baseline to end of study at 12 months
Plasma procollagen type I N-terminal propeptide (PINP, intact and total forms) [µg/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
From baseline to end of study at 12 months
Bone turnover marker: Change in plasma tartrate-resistant acid phosphatase isoform 5b (TRAP5b).
Time Frame: From baseline to end of study at 12 months
Plasma TRAP5b [U/L] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months
From baseline to end of study at 12 months
Kidney function: Stability of kidney graft function based on estimated glomerular filtration rate (GFR) slope
Time Frame: From baseline to end of study at 12 months
From baseline to end of study at 12 months
Change in lower extremity function measured by the 30-second Chair Stand Test at 12 months
Time Frame: From baseline to end of study at 12 months.
Lower extremity function will be assessed using the 30-second Chair Stand Test at baseline and after 12 months. The outcome is the change in the number of repetitions from baseline to 12 months, where a higher number of repetitions indicates better performance.
From baseline to end of study at 12 months.
Change in isometric lower extremity muscle strength
Time Frame: From baseline to end of study at 12 months
Isometric lower extremity muscle strength will be assessed using a dynamometer chair at baseline and after 12 months. The outcome is the change in maximal isometric strength from baseline to 12 months, where higher values indicate greater muscle strength.
From baseline to end of study at 12 months
Change in mobility measured by the Timed Up and Go (TUG) test
Time Frame: From baseline to end of study at 12 months.
Mobility will be assessed using the Timed Up and Go (TUG) test at baseline and after 12 months. The outcome is the change in time (seconds) from baseline to 12 months, where a shorter time indicates better performance.
From baseline to end of study at 12 months.
Change in handgrip strength
Time Frame: From baseline to end of study at 12 months.
Handgrip strength (HGS) test will be performed using a hand dynamometer at baseline and after 12 months. Handgrip strength will be measured in kilograms. The outcome is the change in handgrip strength from baseline to 12 months, where higher values indicate greater muscle strength.
From baseline to end of study at 12 months.
Change in quality of life measured by the Primary Hyperparathyroidism Quality of Life questionnaire (PHPQoL)
Time Frame: From baseline to end of study at 12 months.
Quality of life will be assessed using the Primary Hyperparathyroidism Quality of Life questionnaire (PHPQoL) at baseline and after 12 months. The PHPQoL consists of 16 items assessing health-related quality of life in patients with hyperparathyroidism. Items are scored from 0 to 4 and summed to a total score of 0-64, which is subsequently normalized to a 0-100 scale, where higher scores indicate better quality of life. The outcome is the change in normalized PHPQoL total score from baseline to 12 months.
From baseline to end of study at 12 months.
Change in symptom burden measured by the Parathyroidectomy Assessment of Symptoms (PAS) score
Time Frame: From baseline to end of study at 12 months.
Symptom burden will be assessed using the Parathyroidectomy Assessment of Symptoms (PAS) score at baseline and after 12 months. The PAS score consists of 13 symptom items, each scored from 0 (no symptoms) to 100 (maximum symptom severity), where higher scores indicate greater symptom burden. The outcome is the change in PAS total score from baseline to 12 months.
From baseline to end of study at 12 months.
Change in post-transplant quality of life measured by a SONG (Standardised Outcomes in Nephrology) -based questionnaire
Time Frame: From baseline to end of study at 12 months.
Post-transplant quality of life will be assessed using a questionnaire developed for the post-transplant setting in collaboration with patient representatives (SONG initiative) at baseline and after 12 months. Items are scored using a five-point Likert scale with the response options: Never, Rarely, Sometimes, Usually, Always, with an additional Not applicable option. The outcome is the change in questionnaire score from baseline to 12 months.
From baseline to end of study at 12 months.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Aarhus University Hospital

Collaborators

University of Aarhus

Investigators

  • Principal Investigator: Hanne S Jørgensen, MD, PhD, Department of Nephrology, Aarhus University Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 20, 2026

Primary Completion (Estimated)

December 31, 2030

Study Completion (Estimated)

December 31, 2030

Study Registration Dates

First Submitted

January 23, 2026

First Submitted That Met QC Criteria

February 16, 2026

First Posted (Actual)

February 17, 2026

Study Record Updates

Last Update Posted (Actual)

February 17, 2026

Last Update Submitted That Met QC Criteria

February 16, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 1-10-72-137-25
  • NNF22SA0079901 (Other Grant/Funding Number: the Danish Diabetes and Endocrine Academy, which is funded by the Novo Nordisk Foundation)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data that underlie the results reported in publications will be shared. This includes demographic data, baseline characteristics, outcome measures, and relevant laboratory and imaging data used for primary and secondary analyses. Data will be shared in an anonymized format to protect participant confidentiality. Only data necessary to reproduce the reported results will be made available. Additional data not included in publications will not be routinely shared. Data sharing will be conducted in accordance with applicable data protection regulations and national legislation.

IPD Sharing Time Frame

Beginning after publication of the primary study results and available until December 2035.

IPD Sharing Access Criteria

De-identified (pseudo-anonymized) individual participant data and supporting documents will be made available to qualified researchers upon reasonable request. Requests must include a methodologically sound research proposal. Access will be subject to approval by the principal investigator and relevant institutional authorities. Data sharing will require a data transfer agreement in accordance with the Danish Data Protection Act and the General Data Protection Regulation (GDPR), including Chapter V concerning transfers to third countries. Data will be shared in a secure manner and solely for research purposes.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP
  • ANALYTIC_CODE

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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