title: The impact of multimorbidity status on treatment response in rheumatoid arthritis patients initiating disease-modifying anti-rheumatic drugs.
abstract: OBJECTIVE
  When treating RA patients, remission (REM) or at least low disease activity (LDA) is the ultimate therapeutic goal. The aim of this study was to assess the impact of multimorbidity on achieving REM or LDA.
  
  
  METHODS
  In a prospective RA cohort, we identified patients initiating any DMARD with follow-up data 1 year after. Treatment effects were measured using the clinical disease activity index (CDAI) and the modified health assessment questionnaire (MHAQ); multimorbidity status was assessed using a counted multimorbidity index (cMMI). The proportion of patients reaching REM or LDA 1 year after DMARD commencement with respect to the cMMI was evaluated. In regression models, we calculated the odds ratio of achieving REM or LDA, and predicted CDAI and MHAQ 1 year after DMARD commencement for various levels of cMMI, adjusting for age, sex, disease duration, serostatus, disease activity at DMARD commencement, number of previous DMARDs, and type of DMARD, steroid and NSAID use.
  
  
  RESULTS
  A total of 815 patients started DMARDs; 414 were on the same DMARD after 1 year. The proportion of these patients achieving REM or LDA after 1 year was significantly lower in the patients with higher cMMI, following a linear trend (P < 0.01). After accounting for covariates, the odds ratio for REM associated with each additional morbidity in the cMMI was 0.72 (95% CI 0.55, 0.97) and 0.81 (95% CI 0.70, 0.94) for LDA. One year after DMARD initiation, CDAI (+0.16 per additional morbidity) and MHAQ scores (+0.15 per additional morbidity) were significantly worse (both P < 0.05).
  
  
  CONCLUSIONS
  Increased multimorbidity negatively affects the therapeutic goal of REM and LDA.
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA, Department of Internal Medicine III, Division of Rheumatology, Medical University Vienna, Vienna, Austria and hradner@partners.org.
authors.forename: Helga
authors.initials: H
authors.lastname: Radner
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA, Department of Epidemiology, Harvard School of Public Health, Boston, MA, USA.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Michelle
authors.initials: M
authors.lastname: Frits
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Christine
authors.initials: C
authors.lastname: Iannaccone
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Nancy A
authors.initials: NA
authors.lastname: Shadick
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Weinblatt
authors.affiliation: Department of Internal Medicine III, Division of Rheumatology, Medical University Vienna, Vienna, Austria and.
authors.forename: Josef S
authors.initials: JS
authors.lastname: Smolen
authors.affiliation: Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Solomon
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000503:physiopathology*; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D011446:Prospective Studies; D012044:Regression Analysis; D012074:Remission Induction; D012720:Severity of Illness Index; D013256:Steroids / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D013256:Steroids
keywords: multimorbidity; rheumatoid arthritis; treatment response