title: Accuracy of the diagnoses of spondylarthritides in veterans affairs medical center databases.
abstract: OBJECTIVE
  To study the accuracy of diagnoses of spondylarthritides in computerized databases at the Minneapolis Veterans Affairs Medical Center.
  
  
  METHODS
  Medical records were available and reviewed for a random sample of 184 patients from a cohort of 737 patients seen at the rheumatology clinic between January 1, 2001 and July 31, 2002. We compared 4 database definitions with the medical record gold standard of rheumatologists' diagnosis of ankylosing spondylitis (AS), psoriatic arthritis (PsA), or reactive arthritis (ReA): presence of 1) > or =1 or 2) > or =2 International Classification of Diseases, Ninth Revision (ICD-9) diagnostic codes for diagnoses of AS (720.0), PsA (696.0), and ReA (099.3, 711.11-711.19), and presence of 3) > or =1 or 4) > or =2 ICD-9 codes and prescription of a disease-modifying antirheumatic drug (DMARD). Accuracy was assessed by sensitivity, specificity, positive predictive values (PPVs) and negative predictive values (NPVs), kappa statistic, and receiver operator characteristic (ROC) curve area.
  
  
  RESULTS
  Of 184 patients, 11 (6%) had AS, 17 (9%) had PsA, and 7 (4%) had ReA as per the gold standard. ICD-9 codes for AS, PsA, and ReA were very specific (98-100%) with excellent NPV (99-100%) and PPV (83-100%), good to excellent sensitivity (57-100%), almost perfect kappa agreement (0.72-1), and high ROC curve area (0.79-1). Addition of presence of DMARD prescription to ICD-9 codes of AS and PsA decreased sensitivity to 27-65% without improving the specificity (which was already high at 99-100%).
  
  
  CONCLUSIONS
  The ICD-9 codes for AS, PsA, and ReA in databases are accurate. ICD-9 codes may be used to identify cohorts of patients with spondylarthritides.
authors.affiliation: Minneapolis VA Medical Center, University of Minnesota, Minneapolis 55417, USA. Jasvinder.Singh@va.gov
authors.forename: Jasvinder A
authors.initials: JA
authors.lastname: Singh
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Holmgren
authors.forename: Hollis
authors.initials: H
authors.lastname: Krug
authors.forename: Siamak
authors.initials: S
authors.lastname: Noorbaloochi
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D019540:Area Under Curve; D001499:Bayes Theorem; D016208:Databases, Factual; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D006787:Hospitals, Veterans / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D016347:Medical Records Systems, Computerized / Q000706:statistics & numerical data; D008875:Middle Aged; D008910:Minnesota / Q000453:epidemiology; D011237:Predictive Value of Tests; D000091402:Prohibitins; D012219:Rheumatology / Q000706:statistics & numerical data*; D012680:Sensitivity and Specificity; D025241:Spondylarthritis / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology*; D014728:Veterans / Q000706:statistics & numerical data*
chemical_list: D018501:Antirheumatic Agents; C000717331:PHB2 protein, human; D000091402:Prohibitins