Methods and analysis: Observational and translational open cohort study with prospective collection of clinical data and biological materials in patients with inflammatory rheumatic diseases treated in routine care. Patients contribute one cross-sectional blood sample (i.e. whole blood, serum, EDTA-plasma and -buffy coat, and blood in PAXgene RNA tubes) and/or are enrolled for longitudinal follow-up upon start of new DMARD (blood sampling after 0/3/6/12/24/36/48/60 months' treatment). Demographics, disease characteristics, comorbidities and lifestyle factors are registered at inclusion; DMARD treatment and outcomes are collected repeatedly during follow-up. Currently (June 2017) >5,000 samples from ≈3,000 patients have been collected. Data will be analysed using appropriate statistical analyses.