Serum Biomarkers Analysis in Patients With AR Treated With Anti-TMF

Inclusion Criteria: * Both genders * Over 18 years old * Diagnosis of rheumatoid arthritis according to ACR criteria * Patients that initiate treatment with anti-TNF drugs according to clinical practice, both in naïve anti-TNF patients and patients after first anti-TNF failure * Patients able to follow the protocol requirements * Patients that signed the informed consent Exclusion Criteria: * Patients with known hypersensitivity to investigational products * Patients with tuberculosis, or severe infections like sepsis or opportunistic infections * Patients with moderate/severe cardiac insufficiency (NHYA classification Class III/IV) * Patients that according to the investigator criteria can not participate in the study or complete the study questionnaires * Pregnant or fertile woman that does not use a contraception method