title: How to deal with missing items in BASDAI and BASFI.
authors.affiliation: Department of Clinical Immunology and Rheumatology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands. sofiaramiro@gmail.com.
authors.forename: Sofia
authors.initials: S
authors.lastname: Ramiro
authors.forename: Astrid
authors.initials: A
authors.lastname: van Tubergen
authors.forename: Désirée
authors.initials: D
authors.lastname: van der Heijde
authors.forename: Filip
authors.initials: F
authors.lastname: van den Bosch
authors.forename: Maxime
authors.initials: M
authors.lastname: Dougados
authors.forename: Robert
authors.initials: R
authors.lastname: Landewé
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013167:Spondylitis, Ankylosing / Q000175:diagnosis*; D011795:Surveys and Questionnaires