ANGARD, medical articles, study, research Rheumatic diseases, ankylosing spondylitis, rheumatoid arthritis, register, patients database, cohort, anatolian group for the assessment in rheumatic diseases, anadolu romatizmal hastalıklar araştırma grubu, ASAS, spondiloarthritis, spondilit, ankilozan, romatoid artrit, osteoartrit, recommendations, expert opinion