title: The clinical status and economic savings associated with remission among patients with rheumatoid arthritis: leveraging linked registry and claims data for synergistic insights.
abstract: BACKGROUND
  Treat to target guidelines recommend achieving remission or low disease activity in rheumatoid arthritis (RA). However, the reduction in adverse events and costs associated with lower disease activity is unclear.
  
  
  METHODS
  We used Corrona linked to Medicare data to identify RA patients. Time varying disease activity was measured using Clinical Disease Activity Index (CDAI); outcomes included all-cause hospitalization, a composite of hospitalization or emergency department (ED) visits, mortality, and medical costs. Outcome-specific Cox proportional models evaluated the adjusted hazard ratios between disease activity and outcomes, controlling for potential confounders including comorbidities grouped into four patient phenotypes. Costs were analyzed with mixed models using a Gaussian distribution with log transformation.
  
  
  RESULTS
  Depending on outcome, 4593 RA patients contributed up to 12 001 person years. Median age was 71 years, 75% women. At baseline, approximately 50-60% of patients were in remission or low disease activity. There was a dose-response relationship between RA disease activity (remission, low, moderate, and high) and the incidence of hospitalizations (13.1, 17.8, 21.2, 27.5 per 100 py, respectively); all adjusted hazard ratios were significant: 0.68 (remission), 0.87 (low), and 1.24 (high) compared with moderate disease activity. Similar trends were observed for ED visits and mortality. The crude difference in annual medical costs between remission ($11 145) and moderate disease activity ($17 646) was $-6 500; the adjusted difference (95%CI) was $-3133 (-4737.72, -1528.43).
  
  
  CONCLUSIONS
  Leveraging the benefits of linking registry and administrative data together, lower disease activity in RA was associated with incrementally reduced risks of all-cause hospitalization, ED visits, mortality, and medical costs in a dose-dependent fashion. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Curtis
authors.affiliation: University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Lang
authors.initials: L
authors.lastname: Chen
authors.affiliation: NYU School of Medicine, New York, NY.
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Greenberg
authors.affiliation: University of Massachusetts, Worcester, MA, USA.
authors.forename: Leslie
authors.initials: L
authors.lastname: Harrold
authors.affiliation: University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Meredith L
authors.initials: ML
authors.lastname: Kilgore
authors.affiliation: Albany Medical College, The Center for Rheumatology.
authors.forename: Joel M
authors.initials: JM
authors.lastname: Kremer
authors.affiliation: Brigham and Women's Hospital, Boston, MA, USA.
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Solomon
authors.affiliation: University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Huifeng
authors.initials: H
authors.lastname: Yun
mesh_terms: D000368:Aged; D018501:Antirheumatic Agents / Q000008:administration & dosage / Q000191:economics / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000191:economics / Q000503:physiopathology; D004305:Dose-Response Relationship, Drug; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data; D005260:Female; D017048:Health Care Costs / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D016016:Proportional Hazards Models; D012042:Registries; D012074:Remission Induction; D013997:Time Factors
chemical_list: D018501:Antirheumatic Agents
keywords: Medicare; administrative claims; disease activity; pharmacoepidemiology; registry; rheumatoid arthritis