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.
Studieoversikt
Status
Forhold
Intervensjon / Behandling
Detaljert beskrivelse
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.
Studietype
Registrering (Antatt)
Kontakter og plasseringer
Studiekontakt
- Navn: Clemens Untersulzner, MD
- Telefonnummer: +43 50504 84848
- E-post: clemens.untersulzner@i-med.ac.at
Studer Kontakt Backup
- Navn: Andreas Kronbichler, MD, PhD
- Telefonnummer: +43 50504 25855
- E-post: andreas.kronbichler@i-med.ac.at
Studiesteder
-
-
Tyrol
-
Innsbruck, Tyrol, Østerrike, 6020
- Rekruttering
- Medical University of Innsbruck, Department of Internal Medicine IV, Nephrology and Hypertension
-
Ta kontakt med:
- Clemens Untersulzner, MD
- Telefonnummer: +43 50504 84848
- E-post: clemens.untersulzner@i-med.ac.at
-
Ta kontakt med:
- Andreas Kronbichler, MD, PhD
- Telefonnummer: +43 50504 25855
- E-post: andreas.kronbichler@i-med.ac.at
-
Hovedetterforsker:
- Andreas Kronbichler, MD, PhD
-
Underetterforsker:
- Clemens Untersulzner, MD
-
-
Deltakelseskriterier
Kvalifikasjonskriterier
Alder som er kvalifisert for studier
Tar imot friske frivillige
Kjønn som er kvalifisert for studier
Prøvetakingsmetode
Studiepopulasjon
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.
Beskrivelse
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
Studieplan
Hvordan er studiet utformet?
Designdetaljer
- Observasjonsmodeller: COHORT
- Tidsperspektiver: PROSPECTIVE
Kohorter og intervensjoner
Gruppe / Kohort |
Intervensjon / Behandling |
|---|---|
|
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.
Andre navn:
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. |
Hva måler studien?
Primære resultatmål
Resultatmål |
Tiltaksbeskrivelse |
Tidsramme |
|---|---|---|
|
Proportion of Participants With Clinically Relevant Skeletal Deterioration on HR-pQCT
Tidsramme: 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
Tidsramme: 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
|
Sekundære resultatmål
Resultatmål |
Tiltaksbeskrivelse |
Tidsramme |
|---|---|---|
|
Change in Cortical Thickness
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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)
Tidsramme: 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
Tidsramme: 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
Tidsramme: 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
|
Andre resultatmål
Resultatmål |
Tiltaksbeskrivelse |
Tidsramme |
|---|---|---|
|
Discordance Between DXA and HR-pQCT Classification
Tidsramme: 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
Tidsramme: 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
Tidsramme: Up to 5 years after transplantation
|
Fragility fractures retrieved from routine clinical records without participant contact. |
Up to 5 years after transplantation
|
Samarbeidspartnere og etterforskere
Sponsor
Etterforskere
- Hovedetterforsker: Andreas Kronbichler, MD, PhD, Medical University Innsbruck
Publikasjoner og nyttige lenker
Generelle publikasjoner
- 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.
Studierekorddatoer
Studer hoveddatoer
Studiestart (Faktiske)
Primær fullføring (Antatt)
Studiet fullført (Antatt)
Datoer for studieregistrering
Først innsendt
Først innsendt som oppfylte QC-kriteriene
Først lagt ut (Faktiske)
Oppdateringer av studieposter
Sist oppdatering lagt ut (Faktiske)
Siste oppdatering sendt inn som oppfylte QC-kriteriene
Sist bekreftet
Mer informasjon
Begreper knyttet til denne studien
Nøkkelord
Ytterligere relevante MeSH-vilkår
- Urogenitale sykdommer
- Sykdommer i det endokrine systemet
- Muskel- og skjelettsykdommer
- Patologiske prosesser
- Ernæringsforstyrrelser
- Mannlige urogenitale sykdommer
- Nyresykdommer
- Urologiske sykdommer
- Kvinnelige urogenitale sykdommer
- Kvinnelige urogenitale sykdommer og graviditetskomplikasjoner
- Kronisk sykdom
- Sykdomsattributter
- Metabolske sykdommer
- Parathyreoidea sykdommer
- Avitaminose
- Mangelsykdommer
- Underernæring
- Rakitt
- Forstyrrelser i kalsiummetabolisme
- Vitamin D-mangel
- Hyperparathyroidisme, sekundær
- Hyperparatyreose
- Patologiske tilstander, tegn og symptomer
- Ernæringsmessige og metabolske sykdommer
- Osteoporose
- Beinsykdommer
- Bensykdommer, metabolske
- Kronisk nyresykdom-Mineral- og beinlidelse
- Undersøkelsesteknikker
- Prøvehåndtering
- Kliniske laboratorieteknikker
- Diagnostiske teknikker og prosedyrer
- Diagnose
- Punkteringer
- Kirurgiske prosedyrer, operativ
- Diagnostisk avbildning
- Kjemisteknikker, analytisk
- Radiografi
- Densitometri
- Fotometri
- Absorptiometri, Photon
- Blodprøveinnsamling
Andre studie-ID-numre
- DXACT-003
- 1140/2026 (Annen identifikator: Ethics Committee of the Medical University of Innsbruck)
Plan for individuelle deltakerdata (IPD)
Planlegger du å dele individuelle deltakerdata (IPD)?
IPD-planbeskrivelse
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.
Legemiddel- og utstyrsinformasjon, studiedokumenter
Studerer et amerikansk FDA-regulert medikamentprodukt
Studerer et amerikansk FDA-regulert enhetsprodukt
Denne informasjonen ble hentet direkte fra nettstedet clinicaltrials.gov uten noen endringer. Hvis du har noen forespørsler om å endre, fjerne eller oppdatere studiedetaljene dine, vennligst kontakt register@clinicaltrials.gov. Så snart en endring er implementert på clinicaltrials.gov, vil denne også bli oppdatert automatisk på nettstedet vårt. .