title: Comparative effectiveness of nonbiologic versus biologic disease-modifying antirheumatic drugs for rheumatoid arthritis.
abstract: OBJECTIVE
  To evaluate the comparative effectiveness of nonbiologic disease-modifying antirheumatic drugs (DMARD) versus biologic DMARD (bDMARD) for treatment of rheumatoid arthritis (RA), using 2 common analytic approaches.
  
  
  METHODS
  We analyzed change in Clinical Disease Activity Index (CDAI) scores in patients with RA enrolled in a US-based observational registry from 2001 to 2008 using multivariable (MV) regression and propensity score (PS) matching. Among patients who initiated treatment with a nonbiologic DMARD (n = 1729), we compared patients who switched to, or added, another nonbiologic (n = 182) or a bDMARD (n = 342) at 5, 9, and 24 months after treatment change.
  
  
  RESULTS
  Both analytic approaches showed that patients switching to or adding another nonbiologic DMARD demonstrated improvement across 9 and 24 months (both p < 0.001). Both approaches also demonstrated greater improvement in CDAI among recipients of bDMARD relative to a second nonbiologic DMARD at 5 months (p < 0.02). The MV regression approach upheld these results at 9 and 24 months (p < 0.03). In contrast, the PS-matching approach did not show a sustained advantage with bDMARD at these later timepoints, possibly because of lower statistical power and/or lower baseline disease activity in the PS-matched cohort.
  
  
  CONCLUSIONS
  Patients in both treatment groups generally experienced lower CDAI scores across time. Patients switching to bDMARD demonstrated greater improvement than patients switching to nonbiologic DMARD with both analytic approaches at 5 months. Relative advantages with bDMARD were observed at 9 and 24 months only with MV regression. These analyses provide a practical example of how findings in comparative effectiveness research can diverge with different methodological approaches.
authors: Division of Rheumatology, James M. Anderson Center for Health Systems Excellence, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45229, USA. esi.morgan_dewitt@cchmc.org
authors: Esi Morgan
authors: EM
authors: Dewitt
authors: Yanhong
authors: Y
authors: Li
authors: Jeffrey R
authors: JR
authors: Curtis
authors: Henry A
authors: HA
authors: Glick
authors: Jeffrey D
authors: JD
authors: Greenberg
authors: Kevin J
authors: KJ
authors: Anstrom
authors: Joel M
authors: JM
authors: Kremer
authors: George
authors: G
authors: Reed
authors: Kevin A
authors: KA
authors: Schulman
authors: Shelby D
authors: SD
authors: Reed
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy* / Q000503:physiopathology; D001688:Biological Products / Q000627:therapeutic use*; D015331:Cohort Studies; D057186:Comparative Effectiveness Research / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D057216:Propensity Score; D012042:Registries; D012044:Regression Analysis; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D001688:Biological Products