title: Effect of remission definition on healthcare cost savings estimates for patients with rheumatoid arthritis treated with biologic therapies.
abstract: OBJECTIVE
  Sustained remission in rheumatoid arthritis (RA) results in healthcare utilization cost savings. We evaluated the variation in estimates of savings when different definitions of remission [2011 American College of Rheumatology/European League Against Rheumatism Boolean Definition, Simplified Disease Activity Index (SDAI) ≤ 3.3, Clinical Disease Activity Index (CDAI) ≤ 2.8, and Disease Activity Score-28 (DAS28) ≤ 2.6] are applied.
  
  
  METHODS
  The annual mean healthcare service utilization costs were estimated from provincial physician billing claims, outpatient visits, and hospitalizations, with linkage to clinical data from the Alberta Biologics Pharmacosurveillance Program (ABioPharm). Cost savings in patients who had a 1-year continuous period of remission were compared to those who did not, using 4 definitions of remission.
  
  
  RESULTS
  In 1086 patients, sustained remission rates were 16.1% for DAS28, 8.8% for Boolean, 5.5% for CDAI, and 4.2% for SDAI. The estimated mean annual healthcare cost savings per patient achieving remission (relative to not) were SDAI $1928 (95% CI 592, 3264), DAS28 $1676 (95% CI 987, 2365), and Boolean $1259 (95% CI 417, 2100). The annual savings by CDAI remission per patient were not significant at $423 (95% CI -1757, 2602). For patients in DAS28, Boolean, and SDAI remission, savings were seen both in costs directly related to RA and its comorbidities, and in costs for non-RA-related conditions.
  
  
  CONCLUSIONS
  The magnitude of the healthcare cost savings varies according to the remission definition used in classifying patient disease status. The highest point estimate for cost savings was observed in patients attaining SDAI remission and the least with the CDAI; confidence intervals for these estimates do overlap. Future pharmacoeconomic analyses should employ all response definitions in assessing the influence of treatment.
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta. ccbarnab@ucalgary.ca.
authors.forename: Cheryl
authors.initials: C
authors.lastname: Barnabe
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Nguyen Xuan
authors.initials: NX
authors.lastname: Thanh
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Arto
authors.initials: A
authors.lastname: Ohinmaa
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Joanne
authors.initials: J
authors.lastname: Homik
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Susan G
authors.initials: SG
authors.lastname: Barr
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Liam
authors.initials: L
authors.lastname: Martin
authors.affiliation: From the Department of Medicine, University of Calgary, Calgary; Department of Community Health Sciences, University of Calgary, Calgary; Institute of Health Economics, Edmonton; School of Public Health, University of Alberta, Edmonton; and Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.C. Barnabe, MD, MSc, FRCPC, Department of Medicine and Department of Community Health Sciences, University of Calgary; N.X. Thanh, MD, PhD, MPH, Institute of Health Economics and School of Public Health, University of Alberta; A. Ohinmaa, PhD, Institute of Health Economics and School of Public Health, University of Alberta; J. Homik, MD, MSc, FRCPC, Department of Medicine, University of Alberta; S.G. Barr, MD, MSc, FRCPC, Department of Medicine, and Department of Community Health Sciences, University of Calgary; L. Martin, MB, ChB, FRCPC, Department of Medicine, University of Calgary; W.P. Maksymowych, MB, ChB, FRCPC, Department of Medicine, University of Alberta.
authors.forename: Walter P
authors.initials: WP
authors.lastname: Maksymowych
mesh_terms: D000328:Adult; D000368:Aged; D000416:Alberta; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy* / Q000191:economics; D001688:Biological Products / Q000191:economics* / Q000627:therapeutic use*; D001691:Biological Therapy; D017046:Cost Savings / Q000191:economics*; D003362:Cost-Benefit Analysis; D004185:Disability Evaluation; D017850:Economics, Pharmaceutical; D005260:Female; D017048:Health Care Costs; D006801:Humans; D008297:Male; D008875:Middle Aged; D012074:Remission Induction; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001688:Biological Products
keywords: BIOLOGICS; HEALTHCARE COSTS; OUTCOME ASSESSMENT; REMISSION DEFINITIONS; RHEUMATOID ARTHRITIS