title: Evidence for interaction between disease severity and comorbidity in rheumatoid arthritis? comment on the article by Navarro-Cano et al.
authors.forename: Maarten
authors.initials: M
authors.lastname: Boers
mesh_terms: D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000401:mortality*; D015897:Comorbidity; D006801:Humans; D012720:Severity of Illness Index