RA patients were consecutively included when initiating biologic disease-modifying anti-rheumatic drugs (DMARDs) and assessed at baseline, 1, 2, 3, 6, and 12 months with investigation of fatigue, patient-reported outcome measures (PROMs; joint pain and patient’s global disease activity, MHAQ, pain catastrophizing, Mental Health score), clinical examinations (examiner’s global disease activity, 28 tender and swollen joint counts), and laboratory variables (ESR, CRP, calprotectin). Here, ESR1 is linked to rheumatoid arthritis.