title: Generalisability of clinical registers used for drug safety and comparative effectiveness research: coverage of the Swedish Biologics Register.
abstract: OBJECTIVE
  To determine coverage and generalisability of data in the Swedish Biologics Register ARTIS.
  
  
  METHODS
  Patients with adult onset rheumatoid arthritis (RA) were identified in the National Patient Register and the Swedish Rheumatology Quality Register, including the ARTIS cohort of patients exposed to biological agents. Exposure to etanercept and adalimumab between 2006 and 2008 was determined by register linkage to the Prescribed Drug Register which contains patient-level data on >99% of all etanercept and adalimumab use in Sweden.
  
  
  RESULTS
  Of 62 897 patients with RA, 6510 had received treatment with etanercept or adalimumab according to the Prescribed Drug Register. Of these, 5673 were also registered in ARTIS, resulting in a national coverage of 87%. The regional variation was small with >85% coverage in 18 of 21 counties. In multivariable analysis, ARTIS-registered and non-registered patients did not differ by age (p=0.62), sex (p=0.84) or education level (p=0.24).
  
  
  CONCLUSIONS
  Nationwide drug dispensing and demographic data may function as quality metrics for coverage and generalisability assessments. Using such data, the coverage of ARTIS was estimated at 87% with no indications of compromised external generalisability regarding demography.
authors.affiliation: Department of Medicine, Karolinska Institutet, SE-171 76 Stockholm, Sweden. martin.neovius@ki.se
authors.forename: M
authors.initials: M
authors.lastname: Neovius
authors.forename: Jf
authors.initials: J
authors.lastname: Simard
authors.forename: A
authors.initials: A
authors.lastname: Sundström
authors.forename: L
authors.initials: L
authors.lastname: Jacobsson
authors.forename: P
authors.initials: P
authors.lastname: Geborek
authors.forename: T
authors.initials: T
authors.lastname: Saxne
authors.forename: N
authors.initials: N
authors.lastname: Feltelius
authors.forename: L
authors.initials: L
authors.lastname: Klareskog
authors.forename: J
authors.initials: J
authors.lastname: Askling
mesh_terms: D000068879:Adalimumab; D016907:Adverse Drug Reaction Reporting Systems; D000911:Antibodies, Monoclonal / Q000009:adverse effects / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents / Q000009:adverse effects / Q000627:therapeutic use*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D057186:Comparative Effectiveness Research / Q000379:methods; D011307:Drug Prescriptions / Q000706:statistics & numerical data; D000068800:Etanercept; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000009:adverse effects / Q000627:therapeutic use; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D008498:Medical Record Linkage; D008875:Middle Aged; D018124:Receptors, Tumor Necrosis Factor / Q000627:therapeutic use; D012042:Registries / Q000706:statistics & numerical data*; D013548:Sweden; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D018501:Antirheumatic Agents; D007074:Immunoglobulin G; D007166:Immunosuppressive Agents; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D000068879:Adalimumab; D000068800:Etanercept