title: Propensity-adjusted association of methotrexate with overall survival in rheumatoid arthritis.
abstract: OBJECTIVE
  While medications used to treat rheumatoid arthritis (RA) may affect survival in RA, few studies take into account the propensity for medication use, which may reflect selection bias in treatment allocation in survival models. We undertook this study to examine the relationship between methotrexate (MTX) use and mortality in RA, after controlling for individual propensity scores for MTX use.
  
  
  METHODS
  We studied 5,626 RA patients prospectively for 25 years to determine the risk of death associated with MTX use, modeled in time-varying Cox regression models. We used the random forest method to generate individual propensity scores for MTX use at study entry and during followup in a time-varying manner; these scores were included in the multivariate model. We also investigated whether selective discontinuation of MTX immediately prior to death altered the risk of mortality, and we examined the association of duration of MTX use with survival.
  
  
  RESULTS
  During followup, 666 patients (12%) died. MTX use was associated with reduced risk of death (adjusted hazard ratio 0.30 [95% confidence interval 0.09-1.03]). Selective MTX cessation immediately before death did not account for the protective association of MTX use with mortality. Only MTX use for >1 year was associated with lower risks of mortality, but associations were not stronger with longer durations of use.
  
  
  CONCLUSIONS
  MTX use was associated with a 70% reduction in mortality in RA.
authors.affiliation: West Penn Allegheny Health System, Allegheny Singer Research Institute, 4800 Friendship Avenue, North Tower, Suite 2600, Pittsburgh, PA 15224, USA. mcwasko@wpahs.org
authors.forename: Mary Chester M
authors.initials: MC
authors.lastname: Wasko
authors.forename: Abhijit
authors.initials: A
authors.lastname: Dasgupta
authors.forename: Helen
authors.initials: H
authors.lastname: Hubert
authors.forename: James F
authors.initials: JF
authors.lastname: Fries
authors.forename: Michael M
authors.initials: MM
authors.lastname: Ward
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008727:Methotrexate / Q000627:therapeutic use*; D008875:Middle Aged; D011446:Prospective Studies; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D018501:Antirheumatic Agents; D008727:Methotrexate