Assessment of Nutritional Status in Rheumatic Diseases and Association to Disease Activity

This observational study is investigating nutritional status (including muscle mass and diet) in people with rheumatic diseases to see whether poor nutrition is linked to more severe disease activity. **You may be eligible if...** - You have been diagnosed with a rheumatic disease, including rheumatoid arthritis (RA), spondyloarthritis (SpA), lupus (SLE), or systemic sclerosis (SSc) **You may NOT be eligible if...** - You are unable to participate in physician assessments - You have other connective tissue diseases, neurological conditions, active cancer, heart failure, or severe kidney disease (as these affect muscle mass) - You have advanced liver disease Talk to your doctor to see if this trial is right for you.