An interventional study of Subtotal Parathyroidectomy and Conservative Management in Hyperparathyroidism and Kidney Transplantation Recipients, sponsored by Aarhus University Hospital. Recruiting at 1 site in Denmark. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-06-26.
Sponsored by Aarhus University Hospital · Not applicable, Interventional, and Treatment
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.
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.
110 studies on the registry are indexed under Hyperparathyroidism; 12 are open to participants now.
This study's planned enrollment of 85 is above the median of 53 across 67 interventional studies indexed under Hyperparathyroidism.
Browse Hyperparathyroidism studies →Aarhus University Hospital is the lead sponsor of 298 studies on the registry; 80 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
PTH > upper normal limit of assay and
with measurements obtained within
and not attributable to calcium supplementation or treatment with thiazide diuretics or lithium.
Exclusion criteria
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
GFR and eGFR (kidney filtering)
GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².
Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
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
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
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.
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.
Change in bone mineral density (BMD) at the total hip
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.
Time frame: From baseline to end of study at 12 months
Changes in cortical and trabecular bone microarchitecture
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.
Time frame: From baseline to end of study at 12 months
Mineral metabolism: Change in plasma parathyroid hormone (PTH)
Plasma plasma parathyroid hormone PTH \[pmol/L\] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
Time frame: From baseline to end of study at 12 months
Mineral metabolism: Changes in serum ionized calcium and phosphate
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.
Time frame: From baseline to end of study at 12 months
Mineral metabolism: Change in plasma fibroblast growth factor 23 (FGF23)
Plasma fibroblast growth factor 23 FGF23 \[ng/L\] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months
Time frame: From baseline to end of study at 12 months
Bone turnover marker: Change in bone-specific alkaline phosphatase (BALP)
Bone-specific alkaline phosphataseBALP \[µg/l\] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
Time frame: From baseline to end of study at 12 months
Bone turnover marker: Change in plasma C-terminal crosslinks (CTX)
CTX \[µg/L\] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months.
Time frame: 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)
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.
Time frame: From baseline to end of study at 12 months
Bone turnover marker: Change in plasma tartrate-resistant acid phosphatase isoform 5b (TRAP5b).
Plasma TRAP5b \[U/L\] will be measured at baseline and 12 months. Outcome is change from baseline to 12 months
Time frame: 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
Change in lower extremity function measured by the 30-second Chair Stand Test 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.
Time frame: From baseline to end of study at 12 months.
Change in isometric lower extremity muscle strength
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.
Time frame: From baseline to end of study at 12 months
Change in mobility measured by the Timed Up and Go (TUG) test
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.
Time frame: From baseline to end of study at 12 months.
Change in handgrip strength
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.
Time frame: From baseline to end of study at 12 months.
Change in quality of life measured by the Primary Hyperparathyroidism Quality of Life questionnaire (PHPQoL)
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.
Time frame: From baseline to end of study at 12 months.
Change in symptom burden measured by the Parathyroidectomy Assessment of Symptoms (PAS) score
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.
Time frame: 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
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.
Time frame: From baseline to end of study at 12 months.
Plan to share: Yes — 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.
Supporting information: Study protocol, Statistical analysis plan, Analytic code
Time frame: Beginning after publication of the primary study results and available until December 2035.
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.
Started Mar 2026 (actual). Primary completion is estimated for Dec 2030, 57 months after the start.
Of 18 interventional studies with no phase under Hyperparathyroidism, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 11 and three quarters within 46. This study's planned 57 months is above that.
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