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.
調査の概要
状態
詳細な説明
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.
研究の種類
入学 (推定)
連絡先と場所
研究連絡先
- 名前：Clemens Untersulzner, MD
- 電話番号：+43 50504 84848
- メール：clemens.untersulzner@i-med.ac.at
研究連絡先のバックアップ
- 名前：Andreas Kronbichler, MD, PhD
- 電話番号：+43 50504 25855
- メール：andreas.kronbichler@i-med.ac.at
研究場所
-
-
Tyrol
-
Innsbruck、Tyrol、オーストリア、6020
- 募集
- Medical University of Innsbruck, Department of Internal Medicine IV, Nephrology and Hypertension
-
コンタクト：
- Clemens Untersulzner, MD
- 電話番号：+43 50504 84848
- メール：clemens.untersulzner@i-med.ac.at
-
コンタクト：
- Andreas Kronbichler, MD, PhD
- 電話番号：+43 50504 25855
- メール：andreas.kronbichler@i-med.ac.at
-
主任研究者：
- Andreas Kronbichler, MD, PhD
-
副調査官：
- Clemens Untersulzner, MD
-
-
参加基準
適格基準
就学可能な年齢
健康ボランティアの受け入れ
受講資格のある性別
サンプリング方法
調査対象母集団
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.
説明
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
研究計画
研究はどのように設計されていますか？
デザインの詳細
- 観測モデル：COHORT
- 時間の展望：PROSPECTIVE
コホートと介入
グループ/コホート |
介入・治療 |
|---|---|
|
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.
他の名前：
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. |
この研究は何を測定していますか？
主要な結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
|---|---|---|
|
Proportion of Participants With Clinically Relevant Skeletal Deterioration on HR-pQCT
時間枠：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
時間枠：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
|
二次結果の測定
結果測定 |
メジャーの説明 |
時間枠 |
|---|---|---|
|
Change in Cortical Thickness
時間枠：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
時間枠：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
時間枠：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
時間枠：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
時間枠：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
時間枠：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
時間枠：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
時間枠：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
時間枠：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)
時間枠：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
時間枠：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
時間枠：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
|
その他の成果指標
結果測定 |
メジャーの説明 |
時間枠 |
|---|---|---|
|
Discordance Between DXA and HR-pQCT Classification
時間枠：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
時間枠：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
時間枠：Up to 5 years after transplantation
|
Fragility fractures retrieved from routine clinical records without participant contact. |
Up to 5 years after transplantation
|
協力者と研究者
捜査官
- 主任研究者：Andreas Kronbichler, MD, PhD、Medical University Innsbruck
出版物と役立つリンク
一般刊行物
- 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.
研究記録日
主要日程の研究
研究開始 (実際)
一次修了 (推定)
研究の完了 (推定)
試験登録日
最初に提出
QC基準を満たした最初の提出物
最初の投稿 (実際)
学習記録の更新
投稿された最後の更新 (実際)
QC基準を満たした最後の更新が送信されました
最終確認日
詳しくは
本研究に関する用語
追加の関連 MeSH 用語
- 泌尿生殖器疾患
- 内分泌系疾患
- 筋骨格疾患
- 病理学的プロセス
- 栄養障害
- 男性の泌尿生殖器疾患
- 腎臓病
- 泌尿器疾患
- 女性の泌尿生殖器疾患
- 女性の泌尿生殖器疾患と妊娠合併症
- 慢性疾患
- 疾患の属性
- 代謝疾患
- 副甲状腺疾患
- ビタミン欠乏症
- 欠乏症
- 栄養失調
- くる病
- カルシウム代謝障害
- ビタミンD欠乏症
- 二次性副甲状腺機能亢進症
- 副甲状腺機能亢進症
- 病理学的状態、徴候および症状
- 栄養および代謝疾患
- 骨粗鬆症
- 骨の病気
- 骨疾患、代謝
- 慢性腎臓病 - ミネラルと骨の障害
- 調査手法
- 標本処理
- 臨床検査技術
- 診断技術と手順
- 診断
- パンク
- 外科的処置、手術
- 診断イメージング
- 化学技術、分析
- X線撮影
- 濃度測定
- 測光
- 吸収測定、光子
- 血液標本コレクション
その他の研究ID番号
- DXACT-003
- 1140/2026 (その他の識別子：Ethics Committee of the Medical University of Innsbruck)
個々の参加者データ (IPD) の計画
個々の参加者データ (IPD) を共有する予定はありますか?
IPD プランの説明
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.
医薬品およびデバイス情報、研究文書
米国FDA規制医薬品の研究
米国FDA規制機器製品の研究
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