Bone Deterioration After Kidney Transplantation Assessed by DXA and HR-pQCT (DXACT)
Prospective Imaging-based Assessment of Skeletal Deterioration After Kidney Transplantation Using DXA and HR-pQCT (DXACT Study)
The goal of this observational study is to learn how bone health changes during the first year after kidney transplantation in adults receiving their first kidney transplant.
The main questions it aims to answer are:
- How many patients show a clinically relevant decline in bone density or bone structure within 12 months after transplantation?
- Does a standard bone density scan (DXA) detect these changes as well as a high-resolution scan of bone structure (HR-pQCT)?
Participants will:
- Have a DXA scan of the lower spine, hip and forearm and an HR-pQCT scan of the forearm and lower leg shortly after transplantation and again after 12 months. Participants followed up in Innsbruck may also have these scans after 6 months.
- Give blood and urine samples at the same visits, taken together with routine blood tests whenever possible, for bone and mineral markers and storage in a biobank.
The study does not change any treatment. All treatment decisions remain with the patients' physicians.
Panoramica dello studio
Stato
Stato
Condizioni
Condizioni
Intervento / Trattamento
Intervento / Trattamento
Descrizione dettagliata
Bone mineral density declines rapidly during the first 6-12 months after kidney transplantation, driven by glucocorticoid exposure, persistent chronic kidney disease-mineral and bone disorder (CKD-MBD) and changes in bone turnover. This period coincides with the highest fracture risk. DXA-scans provide areal bone mineral density only and cannot distinguish cortical from trabecular bone or assess microarchitecture, so it may underestimate early cortical deterioration. HR-pQCT measures volumetric bone mineral density, cortical and trabecular microarchitecture and, by finite element analysis, estimated bone strength.
DXACT is an investigator-initiated, prospective, single-centre observational cohort study at the Medical University of Innsbruck. Baseline clinical and laboratory assessment is performed 7 +/- 2 days and imaging 10 +/- 7 days after transplantation; assessments are repeated at 12 months, with an optional 6-month visit for participants followed locally. HR-pQCT is performed at the distal radius and distal tibia of the dominant side (contralateral side if a vascular access or implant is present); DXA at the lumbar spine (L1-L4), hip and distal radius (33%).
Clinically relevant skeletal deterioration is defined as a change exceeding the least significant change (LSC = 2.77 x precision CV) of the respective modality and parameter. Laboratory assessments include parathyroid hormone, 25-hydroxy- and 1,25-dihydroxyvitamin D, calcium, phosphate, P1NP, bone-specific alkaline phosphatase, TRAP5b, CTX, osteocalcin and osteoprotegerin. EDTA plasma and urine are stored in a pseudonymised biobank at -80 °C.
Analyses are primarily descriptive and exploratory. Planned analyses include agreement and discordance between DXA- and HR-pQCT-based classification, associations of imaging changes with biochemical markers and clinical factors (age, sex, dialysis vintage, cumulative glucocorticoid dose, rejection, graft function), and comparison by graft function at 12 months. Incident fragility fractures beyond 12 months may be retrieved from routine clinical records without further participant contact.
Tipo di studio
Tipo di studio
Iscrizione (Stimato)
Iscrizione
Contatti e Sedi
Contatto studio
Contatto studio
- Nome: Clemens Untersulzner, MD
- Numero di telefono: +43 50504 84848
- Email: clemens.untersulzner@i-med.ac.at
Backup dei contatti dello studio
- Nome: Andreas Kronbichler, MD, PhD
- Numero di telefono: +43 50504 25855
- Email: andreas.kronbichler@i-med.ac.at
Luoghi di studio
-
-
Tyrol
-
Innsbruck, Tyrol, Austria, 6020
- Reclutamento
- Medical University of Innsbruck, Department of Internal Medicine IV, Nephrology and Hypertension
-
Contatto:
- Clemens Untersulzner, MD
- Numero di telefono: +43 50504 84848
- Email: clemens.untersulzner@i-med.ac.at
-
Contatto:
- Andreas Kronbichler, MD, PhD
- Numero di telefono: +43 50504 25855
- Email: andreas.kronbichler@i-med.ac.at
-
Investigatore principale:
- Andreas Kronbichler, MD, PhD
-
Sub-investigatore:
- Clemens Untersulzner, MD
-
-
Criteri di partecipazione
Criteri di ammissibilità
Criteri di ammissibilità
Età idonea allo studio
Accetta volontari sani
Sessi ammissibili allo studio
Metodo di campionamento
Popolazione di studio
Adult recipients of a first kidney transplant (living or deceased donor) treated at the Medical University of Innsbruck, Austria, who are approached by the study team within 10 days after transplantation.
Descrizione
Inclusion Criteria:
- Age 18 years or older at the time of kidney transplantation
- First kidney transplantation (living or deceased donor)
- Ability and willingness to provide written informed consent
- Enrolment possible within 10 days after kidney transplantation
- Clinical stability sufficient to undergo imaging procedures
Exclusion Criteria:
- Previous kidney transplantation
- Prior or ongoing treatment with antiresorptive or osteoanabolic therapies (e.g. bisphosphonates, denosumab, teriparatide) at the time of transplantation
- Conditions precluding reliable bone imaging, including metal implants at the measurement sites
- Contraindications to HR-pQCT or DXA
- Inability to undergo imaging due to physical or technical limitations
- Known metabolic bone diseases unrelated to chronic kidney disease-mineral and bone disorder (CKD-MBD)
- Any condition that, in the opinion of the investigator, would interfere with study participation, data quality or protocol adherence
Piano di studio
Come è strutturato lo studio?
Dettagli di progettazione
- Modelli osservazionali: COHORT
- Prospettive temporali: PROSPECTIVE
Numero di gruppi/coorti
Coorti e interventi
Gruppo / CoorteGruppo / Coorte |
Intervento / TrattamentoIntervento / Trattamento |
|---|---|
|
Kidney transplant recipients
Adults (18 years or older) who received a first kidney transplant (living or deceased donor) at the Medical University of Innsbruck and are enrolled within 10 days after transplantation. |
Dual-energy X-ray absorptiometry of the lumbar spine (L1-L4), hip and distal radius (33%) and high-resolution peripheral quantitative computed tomography of the distal radius and distal tibia, performed at baseline (10 +/- 7 days after kidney transplantation) and at 12 months, with an optional 6-month visit. Imaging is used for research only; no treatment is assigned.
Altri nomi:
Blood and urine samples at each study visit, taken together with routine blood draws, for markers of bone and mineral metabolism and storage in a biobank. |
Cosa sta misurando lo studio?
Misure di risultato primarie
Misure di risultato primarie
Misura del risultato |
Misura Descrizione |
Lasso di tempo |
|---|---|---|
|
Proportion of Participants With Clinically Relevant Skeletal Deterioration on HR-pQCT
Lasso di tempo: Baseline (10 +/- 7 days after transplantation) to 12 months
|
Deterioration exceeding the least significant change (LSC = 2.77 x precision CV) in at least one of cortical thickness, cortical porosity or finite element-derived failure load at the distal radius or distal tibia. |
Baseline (10 +/- 7 days after transplantation) to 12 months
|
|
Proportion of Participants With Clinically Relevant Skeletal Deterioration on DXA
Lasso di tempo: Baseline (10 +/- 7 days after transplantation) to 12 months
|
Decrease in areal bone mineral density exceeding the site-specific least significant change at the lumbar spine (L1-L4), hip or distal radius (33%). |
Baseline (10 +/- 7 days after transplantation) to 12 months
|
Misure di risultato secondarie
Misure di risultato secondarie
Misura del risultato |
Misura Descrizione |
Lasso di tempo |
|---|---|---|
|
Change in Cortical Thickness
Lasso di tempo: Baseline to 12 months
|
Absolute (mm) and relative (%) change in cortical thickness at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Cortical Porosity
Lasso di tempo: Baseline to 12 months
|
Absolute (percentage points) and relative change in cortical porosity at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Total Volumetric BMD
Lasso di tempo: Baseline to 12 months
|
Absolute (mg HA/cm³) and relative (%) change in total volumetric bone mineral density at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Cortical Volumetric BMD
Lasso di tempo: Baseline to 12 months
|
Absolute (mg HA/cm³) and relative (%) change in cortical volumetric bone mineral density at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Trabecular Volumetric BMD
Lasso di tempo: Baseline to 12 months
|
Absolute (mg HA/cm³) and relative (%) change in trabecular volumetric bone mineral density at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Trabecular Number
Lasso di tempo: Baseline to 12 months
|
Absolute (1/mm) and relative (%) change in trabecular number at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Trabecular Thickness
Lasso di tempo: Baseline to 12 months
|
Absolute (mm) and relative (%) change in trabecular thickness at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Trabecular Separation
Lasso di tempo: Baseline to 12 months
|
Absolute (mm) and relative (%) change in trabecular separation at the distal radius and distal tibia measured by HR-pQCT. |
Baseline to 12 months
|
|
Change in Biochemical Markers of Bone and Mineral Metabolism
Lasso di tempo: Baseline to 12 months
|
Change in parathyroid hormone, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, phosphate, P1NP, bone-specific alkaline phosphatase, TRAP5b, CTX, osteocalcin and osteoprotegerin |
Baseline to 12 months
|
|
Change in Estimated Bone Strength (Failure Load)
Lasso di tempo: Baseline to 12 months
|
Absolute and relative change in finite element-derived failure load (N) at the distal radius and distal tibia. |
Baseline to 12 months
|
|
Change in Areal Bone Mineral Density
Lasso di tempo: Baseline to 12 months
|
Absolute and relative change in areal BMD (g/cm2) at the lumbar spine (L1-L4), total hip, femoral neck and distal radius (33%) measured by DXA. |
Baseline to 12 months
|
|
Skeletal Changes by Graft Function
Lasso di tempo: 12 months
|
Comparison of HR-pQCT and DXA changes between participants with eGFR >= 60 and < 60 mL/min/1.73 m2 (CKD-EPI 2021) at 12 months. |
12 months
|
Altre misure di risultato
Altre misure di risultato
Misura del risultato |
Misura Descrizione |
Lasso di tempo |
|---|---|---|
|
Discordance Between DXA and HR-pQCT Classification
Lasso di tempo: 12 months
|
Proportion of participants classified differently by DXA and HR-pQCT, in particular stable DXA with deterioration on HR-pQCT. |
12 months
|
|
Association of Dialysis Vintage With Skeletal Deterioration
Lasso di tempo: Baseline to 12 months
|
Pre-transplant dialysis duration (continuous; pre-emptive, < 12, >= 12 months) as predictor of imaging-derived skeletal changes. |
Baseline to 12 months
|
|
Incident Fragility Fractures
Lasso di tempo: Up to 5 years after transplantation
|
Fragility fractures retrieved from routine clinical records without participant contact. |
Up to 5 years after transplantation
|
Collaboratori e investigatori
Sponsor
Sponsor
Investigatori
Investigatori
- Investigatore principale: Andreas Kronbichler, MD, PhD, Medical University Innsbruck
Pubblicazioni e link utili
Pubblicazioni generali
- Jorgensen HS, Behets G, Bammens B, Claes K, Meijers B, Naesens M, Sprangers B, Kuypers DRJ, Cavalier E, D'Haese P, Evenepoel P. Natural History of Bone Disease following Kidney Transplantation. J Am Soc Nephrol. 2022 Mar;33(3):638-652. doi: 10.1681/ASN.2021081081. Epub 2022 Jan 19.
- Evenepoel P, Claes K, Meijers B, Laurent MR, Bammens B, Naesens M, Sprangers B, Pottel H, Cavalier E, Kuypers D. Bone mineral density, bone turnover markers, and incident fractures in de novo kidney transplant recipients. Kidney Int. 2019 Jun;95(6):1461-1470. doi: 10.1016/j.kint.2018.12.024. Epub 2019 Mar 4.
- Untersulzner C, Pirklbauer M, Evenepoel P, Zoller H, Kronbichler A. Bone Mineral Density Loss After Kidney Transplantation: Metabolic Determinants, Diagnostic Approaches, and Preventive Strategies. Kidney Int Rep. 2026 Jun 30;11(9):106685. doi: 10.1016/j.ekir.2026.106685. eCollection 2026 Sep.
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Inizio studio (Effettivo)
Inizio studio
Completamento primario (Stimato)
Completamento primario
Completamento dello studio (Stimato)
Completamento dello studio
Date di iscrizione allo studio
Primo inviato
Primo inviato
Primo inviato che soddisfa i criteri di controllo qualità
Primo inviato che soddisfa i criteri di controllo qualità
Primo Inserito (Effettivo)
Primo Inserito
Aggiornamenti dei record di studio
Ultimo aggiornamento pubblicato (Effettivo)
Ultimo aggiornamento pubblicato
Ultimo aggiornamento inviato che soddisfa i criteri QC
Ultimo aggiornamento inviato che soddisfa i criteri QC
Ultimo verificato
Ultimo verificato
Maggiori informazioni
Termini relativi a questo studio
Parole chiave
Termini MeSH pertinenti aggiuntivi
- Malattie urogenitali
- Malattie del sistema endocrino
- Malattie muscoloscheletriche
- Processi patologici
- Disturbi della nutrizione
- Malattie urogenitali maschili
- Malattie renali
- Malattie urologiche
- Malattie urogenitali femminili
- Malattie urogenitali femminili e complicanze della gravidanza
- Malattia cronica
- Attributi della malattia
- Malattie metaboliche
- Malattie paratiroidee
- Avitaminosi
- Malattie da carenza
- Malnutrizione
- Rachitismo
- Disturbi del metabolismo del calcio
- Carenza di vitamina D
- Iperparatiroidismo, secondario
- Iperparatiroidismo
- Condizioni patologiche, segni e sintomi
- Malattie nutrizionali e metaboliche
- Osteoporosi
- Malattie ossee
- Malattie ossee, metaboliche
- Malattia renale cronica - Disturbo minerale e osseo
- Tecniche investigative
- Gestione dei campioni
- Tecniche di laboratorio clinico
- Tecniche e procedure diagnostiche
- Diagnosi
- Forature
- Procedure chirurgiche, operative
- Imaging diagnostico
- Tecniche di chimica, analitiche
- Radiografia
- Densitometria
- Fotometria
- Assorbtiometria, fotone
- Collezione di campioni di sangue
Altri numeri di identificazione dello studio
Altri numeri di identificazione dello studio
- DXACT-003
- 1140/2026 (Altro identificatore: Ethics Committee of the Medical University of Innsbruck)
Piano per i dati dei singoli partecipanti (IPD)
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Descrizione del piano IPD
Individual participant data will not be shared publicly, as participant consent does not cover transfer to third parties. De-identified data may be made available by the study lead upon reasonable request, subject to approval by the ethics committee and data protection regulations.
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