title: Rheumatoid arthritis disease activity and disability affect the risk of serious infection events in RADIUS 1.
abstract: OBJECTIVE
  To determine whether disease activity and disability independently correlate with serious infection event (SIE) risk in a large rheumatoid arthritis (RA) cohort.
  
  
  METHODS
  The associations between SIE and Clinical Disease Activity Index (CDAI) and Health Assessment Questionnaire-Disability Index (HAQ-DI) in the Rheumatoid Arthritis Disease-Modifying Antirheumatic Drug Intervention and Utilization Study (RADIUS 1) cohort were evaluated using the Andersen-Gill model (a proportional HR model allowing > 1 event per patient).
  
  
  RESULTS
  Of 4084 patients with 347 SIE, 271 patients experienced ≥ 1 SIE. A 5-unit CDAI increase and 0.4-unit HAQ-DI increase corresponded to an increase in SIE risk with and without covariate adjustments. A 5-unit CDAI increase corresponded with a 7.7% increased SIE risk (adjusted HR 1.077, 95% CI 1.044-1.112, p < 0.0001) and a 0.4-unit HAQ-DI increase with a 30.1% increased risk (adjusted HR 1.301, 95% CI 1.225-1.381, p < 0.0001). Categorical analysis showed that more severe RA activity (even after controlling for disability) and disability were associated with an increased SIE risk.
  
  
  CONCLUSIONS
  Increased RA disease activity and disability were each associated with a significantly increased SIE risk in the RADIUS 1 cohort, which could not be completely accounted for by disability.
authors.affiliation: University of Nebraska Medical Center, Omaha, Nebraska, USA. arthur.weaver@earthlink.net
authors.forename: Arthur
authors.initials: A
authors.lastname: Weaver
authors.forename: Orrin
authors.initials: O
authors.lastname: Troum
authors.forename: Michele
authors.initials: M
authors.lastname: Hooper
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Koenig
authors.forename: Sandeep
authors.initials: S
authors.lastname: Chaudhari
authors.forename: Jingyuan
authors.initials: J
authors.lastname: Feng
authors.forename: Deborah
authors.initials: D
authors.lastname: Wenkert
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007239:Infections / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
chemical_list: D018501:Antirheumatic Agents
keywords: ANTIRHEUMATIC DRUGS; DISEASE-MODIFYING ANTIRHEUMATIC DRUGS; INFECTION; RHEUMATOID ARTHRITIS