Table 1 Eligibility criteria for participants with chronic liver disease, rheumatoid arthritis or inflammatory bowel disease

CLD, IBD and RA

1. A formal confirmed diagnosis of their underlying chronic inflammatory condition:

IBD cohort patients will have endoscopic or radiological evidence.

Some of the CLD cohorts will have had a liver biopsy, serological and radiological confirmation will be sufficient.

 a. RA cohort, clinical, serological and radiological confirmation will be sufficient.

 b. Biologic therapy naïve on recruitment or commencing a new biologic if in the IBD or IA cohort.

2. Adults aged ≥ 18 years

3. Able to confirm written consent to the study

4. Biologic therapy naïve on recruitment or commencing a new biologic if in the IBD or RA cohort

Pre-existing or current use of immunosuppressant agents or Disease Modifying Antirheumatic Drugs (DMARDs) are acceptable in all cohorts.

5. Meeting ACR (American College of Rheumatology)/EULAR (European League Against Rheumatism) 2010 or ACR 1987 Criteria for rheumatoid arthritis and starting DMARD therapy.

6. Meeting criteria of an inflammatory arthritis as per the American College of Rheumatology

7. Meeting criteria of liver cirrhosis including all Child Pugh scores from A-C as per British Association for the Study of the Liver guidance.

8. Meeting criteria for IBD as per the British Society of Gastroenterology guidance.

9. For muscle biopsy sampling (does not preclude patients from participating if they do not meet the below criteria)

INR ≤ 1.6

Platelet count > 30

1. Refusal or lack capacity to give informed consent.

2. Currently enrolled in an interventional trial with active treatment for their chronic disease condition.

3. Previously undergone LT or biliary intervention in the CLD cohort.

4. Underlying or active cancer.

5. Biliary intervention if CLD

6. For Muscle biopsies only (able to continue in study):

 a. Obvious injury to both thighs.

 b. Active bleeding of site, pre-procedure,

 c. Abnormal observation parameters.

 d. Acute illness.

 e. INR > 1.6.

 f. Platelet count < 30.

 g. Anticoagulation which cannot be paused due to increased risk to pre-existing comorbidity.

7. For undergoing an MRI

 a. Pacemaker.

 b. Metal work inserted that is not MRI compatible or further information cannot be obtained.

Healthy controls

1. Adults aged ≥ 18 years.

2. Able to confirm written consent to the study.

3. No co-existing chronic inflammatory condition, cancer or significant premorbid disease pathology.

4. No suspicion or evidence of sarcopenia.

5. No previous transplantation.

1. Refusal or lack capacity to give informed consent.

2. Pregnancy.

3. Any recent acute illness or surgery requiring significant treatment or hospitalisation (within the last 12 weeks).

4. Any systemic corticosteroid use or replacement.

5. For muscle biopsies only:

 a. Obvious injury to both thighs.

 b. Active bleeding of site, pre-procedure.

 c. Abnormal observation parameters.

 d. Acute illness.

 e. INR > 1.6.

 f. Platelet count < 30.

 g. Anticoagulation which cannot be paused due to increased risk to pre-existing comorbidity.