Critical Illness Myopathy and Trajectory of Recovery in AKI Requiring CRRT

Study Overview
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Brief Summary
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The purpose of this study is to determine whether patients with acute kidney injury requiring renal replacement therapy have a higher incidence of muscle wasting than controls and whether the course of recovery is longer compared to controls.

Detailed Description
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Acute kidney injury (AKI), the abrupt loss of kidney function, is a common complication that affects more than half of all intensive care unit (ICU) admissions, and it is associated with substantially higher rates of morbidity and mortality in both the short- and the long-term. This is especially true in patients with AKI requiring renal replacement therapy (AKI-RRT), also known as dialysis. An understudied mechanism by which AKI-RRT may contribute to poor clinical outcomes, both in the hospital and after discharge, is through its impact on muscle mass and muscle function. AKI of any severity is known to alter tissue utilization of amino acids, and preliminary data suggest that RRT in the ICU may exacerbate muscle dysfunction through the removal of large quantities of amino acids from the patient's plasma. This study will determine whether patients with AKI-RRT have greater lean muscle loss over 1 week than historical critically ill controls, whether patients with AKI-RRT have diminished recovery of muscle mass and function at 1-3 months following discharge compared to controls, and whether changes in plasma levels of amino acids during hospitalization correlate with loss of muscle function or lack of recovery.

Official Title
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Critical Illness Myopathy and Trajectory of Recovery in Acute Kidney Injury (AKI) Requiring Continuous Renal Replacement Therapy (CRRT): A Prospective Observational Trial

Conditions
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Acute Kidney Injury, Critical Illness Myopathy, Dialysis; Complications

Intervention / Treatment
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* Diagnostic Test: Musculoskeletal ultrasound
* Diagnostic Test: Assessments of muscle strength and physical function
* Diagnostic Test: Metabolomics


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: >18 years old AKI requiring CRRT, with enrollment within 48 hours of CRRT initiation Exclusion Criteria: ICU admission for >7 days RRT of any kind at any time prior to ICU admission Chronic kidney disease (CKD) with estimated glomerular filtration rate <20 mL/min/1.73 m2 as calculated by the 2021 CKD-EPI equation underlying muscle disorders or muscle atrophy such as quadriplegia or hemiplegia, stroke with residual motor deficits, end-stage liver disease, active alcohol use disorder, active malignancy (other than non-melanoma skin cancer) within 1 year, burns, or other baseline neuromuscular disease pregnancy concomitant use of other extracorporeal support devices such as ventricular assist devices or extracorporeal membrane oxygenation anticipated inability to engage in weight-bearing testing after discharge (e.g., trauma or orthopedic surgery) subjects will be ineligible for outpatient testing if they remain on RRT in the week prior to the research appointment

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 89 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| AKI-RRT<br>Adults admitted to the ICU with AKI requiring CRRT with study enrollment within 48 hours of CRRT initiation. | Diagnostic Test: Musculoskeletal ultrasound<br>* Ultrasound of rectus femoris to determine cross-sectional area, muscle thickness, echo intensity.<br>Diagnostic Test: Assessments of muscle strength and physical function<br>* A battery of tests of physical function and muscle strength (see outcomes section for details).<br>Diagnostic Test: Metabolomics<br>* Using metabolomic analysis, concentrations of amino acids and other important analytes will be measured in patient plasma and CRRT effluent<br>|
| Historical Controls<br>The controls for the ICU phase will be 41 critically ill adults without AKI-RRT in whom similar measurements of muscle size, quality, and function were collected in a recent prior study [PubMed ID: 33148301]. The controls for the recovery phase will come from an ongoing prospective observational study being performed at the University of Kentucky, which will include outpatient functional assessments performed on 200 ICU survivors (NCT05537298). | Diagnostic Test: Musculoskeletal ultrasound<br>* Ultrasound of rectus femoris to determine cross-sectional area, muscle thickness, echo intensity.<br>Diagnostic Test: Assessments of muscle strength and physical function<br>* A battery of tests of physical function and muscle strength (see outcomes section for details).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ICU Stage: rectus femoris (RF) cross-sectional area (CSA) | RF CSA as assessed by musculoskeletal ultrasound (MSKUS) will be measured at day 0 (study enrollment within 48 hours of CRRT initiation), at day 3, and at day 7 (or at ICU discharge if before day 7). | 7 days | 
| ICU Stage: RF muscle thickness (mT) | RF mT as assessed by MSKUS will be measured at day 0 (study enrollment within 48 hours of CRRT initiation), at day 3, and at day 7 (or at ICU discharge if before day 7). | 7 days | 
| ICU Stage: RF echo intensity (EI) | RF EI as assessed by MSKUS will be measured at day 0 (study enrollment within 48 hours of CRRT initiation), at day 3, and at day 7 (or at ICU discharge if before day 7). | 7 days | 
| RF CSA at discharge | RF CSA as assessed by MSKUS will be measured at hospital discharge. | 1 month | 
| RF mT at discharge | RF mT as assessed by MSKUS will be measured at hospital discharge. | 1 month | 
| RF EI at discharge | RF EI as assessed by MSKUS will be measured at hospital discharge. | 1 month | 
| RF CSA at post-discharge outpatient visit | RF CSA as assessed by MSKUS will be measured at outpatient follow-up visit. | 1-3 months | 
| RF mT at post-discharge outpatient visit | RF mT as assessed by MSKUS will be measured at outpatient follow-up visit. | 1-3 months | 
| RF EI at post-discharge outpatient visit | RF mT as assessed by MSKUS will be measured at outpatient follow-up visit. | 1-3 months | 
| ICU Stage: ICU Mobility Scale | The ICU Mobility Scale is an 11-point scale ranging from 0-10 which involves scoring a patient's maximum level of mobility in the prior 24-hour period. The ICU Mobility Scale will be performed at the same 3 time points as the MSKUS assessments. | 7 days | 
| Muscle Strength - Medical Research Council Sum-score (MRC-ss) at discharge | MRC-ss is a measure of global peripheral muscle strength that is the current clinical standard for diagnosing ICU-acquired weakness. Muscle strength is assessed by physical exam and rated on an ordinal scale (0-5) at six bilateral muscle groups: shoulder abductors, elbow flexors, wrist extensors, hip flexors, knee extensors, and ankle dorsiflexors. | 1 month | 
| Muscle Strength - MRC-ss at post-discharge outpatient visit | MRC-ss is a measure of global peripheral muscle strength that is the current clinical standard for diagnosing ICU-acquired weakness. Muscle strength is assessed by physical exam and rated on an ordinal scale (0-5) at six bilateral muscle groups: shoulder abductors, elbow flexors, wrist extensors, hip flexors, knee extensors, and ankle dorsiflexors. | 1-3 months | 
| Muscle Strength - knee extension by hand-held dynamometry (HHD) at hospital discharge | Maximal isometric knee extensor muscle strength as measured by HHD. | 1 month | 
| Muscle Strength - knee extension by HHD at post-discharge outpatient visit | Maximal isometric knee extensor muscle strength as measured by HHD. | 1-3 months | 
| Muscle Strength - Grip Strength at hospital discharge | Maximal isometric grip strength as measured by hand-grip dynamometry (HGD) | 1 month | 
| Muscle Strength - Grip Strength at post-discharge outpatient visit | Maximal isometric grip strength as measured by HGD | 1-3 months | 
| Physical Function - Short Physical Performance Battery (SPPB) at discharge | SPPB is a performance-based composite test with a total of 12 points including components of balance (side-by-side stand, semi-tandem stand, and full-tandem stand), chair-to-stand test, and 4-meter habitual gait speed used to assess physical function and physical frailty. | 1 month | 
| Physical Function - SPPB at post-discharge outpatient visit | SPPB is a performance-based composite test with a total of 12 points including components of balance (side-by-side stand, semi-tandem stand, and full-tandem stand), chair-to-stand test, and 4-meter habitual gait speed used to assess physical function and physical frailty. | 1-3 months | 
| TUG Test at post-discharge outpatient visit | The Timed Up and Go (TUG) test assesses the time (in seconds) for a subject to stand on command from a seated position, walk 3 meters, turn around, walk back to the chair, and sit down, thereby assessing mobility, physical function, and fall risk. | 1-3 months | 
| Physical Function - 6-minute walk test (6MWT) at post-discharge outpatient visit | The 6MWT assesses the distance a subject can walk in six minutes, providing a global representation of physical function and cardiopulmonary endurance. | 1-3 months | 
| Quality of Life testing using EuroQol Group 5-dimension 5-level (EQ-5D-5L) questionnaire at post-discharge outpatient visit | The EQ-5D-5L is a standardized measure of health status developed by the Euro-Qol Group to provide an assessment of health for clinical and economic appraisal. | 1-3 months | 
| Physical Function - Clinical Frailty Scale (CFS) at post-discharge outpatient visit | CFS is a widely adopted judgement-based tool to screen for frailty and to broadly stratify degrees of fitness and frailty. | 1-3 months | 
| Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) Questionnaire at post-discharge outpatient visit | The FACIT-F scale is a 13-item measure that assesses self-reported fatigue and its impact upon daily activities and function. | 1-3 months | 
| 36-Item Short Form Health Survey Physical Function Scale (SF-36) at post-discharge outpatient visit | The SF-36 is a 36-item patient-reported survey of health commonly used to evaluate adult patients which contains 8 domains, including a physical function scale based on 10 of the 36 items which has been shown to have high reliability. | 1-3 months | 
| Return to driving | Yes / No outcome assessed at the outpatient follow-up visit | 1-3 months | 
| Return to work or hobby | Yes / No outcome assessed at the outpatient follow-up visit | 1-3 months | 
| Hospital Readmission | Yes / No outcome assessed at the outpatient follow-up visit | 1-3 months | 
| Emergency Department Visit | Yes / No outcome assessed at the outpatient follow-up visit | 1-3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| ICU Stage: Changes in Plasma Metabolome | Plasma samples will be obtained at day 0 (study enrollment within 48 hours of CRRT initiation), at day 3, and at day 7 (or at ICU discharge if before day 7) and metabolomic analysis will be performed to determine if changes in the plasma metabolome with CRRT initiation correlate with parameters of muscle wasting and/or trajectory of recovery of muscle weakness. | 7 days | 
| ICU Stage: Changes in CRRT Effluent Metabolome | CRRT effluent samples will be obtained at day 0 (study enrollment within 48 hours of CRRT initiation), at day 3, and at day 7 (or at ICU discharge if before day 7) and metabolomic analysis will be performed to determine if changes in the effluent metabolome with CRRT initiation correlate with parameters of muscle wasting and/or trajectory of recovery of muscle weakness. | 7 days |