title: The Detection of Rheumatic Disease through Hospital Diagnoses with Examples of Rheumatoid Arthritis and Giant Cell Arteritis: What Are We Missing?
abstract: OBJECTIVE
  We examined hospitalizations for patients with known rheumatoid arthritis (RA) or giant cell arteritis (GCA) to evaluate whether hospitalization-related diagnoses accurately identified patients with rheumatologic diseases.
  
  
  METHODS
  Diagnosis codes for hospitalizations in 1996-2012 among previously identified population-based cohorts of patients with RA or GCA were examined for RA or GCA mentions.
  
  
  RESULTS
  RA or GCA mention occurred in only 55% of 2407 hospitalizations among patients with RA and 31% of 502 hospitalizations among patients with GCA. RA or GCA was mentioned more often in recent years, younger patients, and rheumatic medication users.
  
  
  CONCLUSIONS
  Coding for RA or GCA during hospitalizations was often missed. Research using hospital diagnoses alone could be biased.
authors.affiliation: From the Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.C.J. Michet III, Division of Rheumatology, Department of Internal Medicine, Mayo Clinic; C.S. Crowson, MS, Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; S.J. Achenbach, MS, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; E.L. Matteson, MD, MPh, Division of Rheumatology, Department of Internal Medicine, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic.
authors.forename: C
authors.initials: C
authors.lastname: John Michet
authors.affiliation: From the Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.C.J. Michet III, Division of Rheumatology, Department of Internal Medicine, Mayo Clinic; C.S. Crowson, MS, Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; S.J. Achenbach, MS, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; E.L. Matteson, MD, MPh, Division of Rheumatology, Department of Internal Medicine, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic.
authors.forename: Cynthia S
authors.initials: CS
authors.lastname: Crowson
authors.affiliation: From the Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.C.J. Michet III, Division of Rheumatology, Department of Internal Medicine, Mayo Clinic; C.S. Crowson, MS, Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; S.J. Achenbach, MS, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; E.L. Matteson, MD, MPh, Division of Rheumatology, Department of Internal Medicine, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic.
authors.forename: Sara J
authors.initials: SJ
authors.lastname: Achenbach
authors.affiliation: From the Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic, Rochester, Minnesota, USA.C.J. Michet III, Division of Rheumatology, Department of Internal Medicine, Mayo Clinic; C.S. Crowson, MS, Division of Rheumatology, Department of Internal Medicine, and Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; S.J. Achenbach, MS, Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic; E.L. Matteson, MD, MPh, Division of Rheumatology, Department of Internal Medicine, and Division of Epidemiology, Department of Health Sciences Research, Mayo Clinic. Matteson.Eric@mayo.edu.
authors.forename: Eric L
authors.initials: EL
authors.lastname: Matteson
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D003937:Diagnosis, Differential; D005260:Female; D013700:Giant Cell Arteritis / Q000175:diagnosis* / Q000453:epidemiology*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D033162:Incidental Findings; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D020380:Needs Assessment; D012189:Retrospective Studies; D012216:Rheumatic Diseases / Q000175:diagnosis / Q000453:epidemiology; D018570:Risk Assessment; D017678:Sex Distribution; D014481:United States
keywords: CODING; DIAGNOSIS; GIANT CELL ARTERITIS; HOSPITALIZATION; INTERNATIONAL CLASSIFICATION OF DISEASE; RHEUMATOID ARTHRITIS