title: Validity of the COPCORD core questionnaire as a classification tool for rheumatic diseases.
abstract: OBJECTIVE
  Rheumatic diseases are vastly underdiagnosed and undertreated, particularly among minorities and those of low socioeconomic status. The WHO-ILAR Community Oriented Program in the Rheumatic Diseases (COPCORD) advocates screening of musculoskeletal complaints in the community. The objective of this study was to evaluate the performance of the COPCORD Core Questionnaire (CCQ) as a diagnostic tool for rheumatic diseases.
  
  
  METHODS
  We conducted a cross-sectional study designed in parallel with a large COPCORD survey in Mexico. A subsample of 17,566 questionnaires, selected from 4 of the 5 states included in a national COPCORD survey were included in the analysis as a diagnostic test to evaluate sensitivity, specificity, receiver operating characteristics curve (ROC), and positive likelihood ratio (LR+) of the CCQ as a case-detection tool for rheumatic diagnosis and for the most frequent diagnoses identified in the survey, osteoarthritis, regional rheumatic pain syndromes, and rheumatoid arthritis (RA). Logistic regression with the questions with LR+ ≥ 1 was performed to identify the strength of association (OR) for each question.
  
  
  RESULTS
  Pain in the last 7 days, high pain score (> 4), and previous diagnosis were the questions with highest LR+ for diagnosis, and for diagnosis of RA treatment with NSAID. The variables that contributed most to the model were pain in the last 7 days (OR 2.0, 95% CI 1.8-2.3), NSAID treatment (OR 3.3, 95% CI 3.0-3.7), a high pain score (OR 1.15, 95% CI 1.13-1.17), and having a previous diagnosis (OR 1.4, 95% CI 1.3-1.6). These 4 questions had R(2) = 0.24, p < 0.01, for detection of any rheumatic diagnosis. The single variable that explains 16% (OR 1.33, 95% CI 1.31-134) of variance was a high pain score in the last 7 days.
  
  
  CONCLUSIONS
  Some variables were identified in the CCQ that could be combined in a brief version for case detection of rheumatic diseases in community surveys. The validity of this proposal has to be tested against the original version.
authors.affiliation: Unidad de Investigación, HGR No. 1 IMSS, Colegio Mexicano de Reumatología, México City, Mexico.
authors.forename: Maria-Victoria
authors.initials: MV
authors.lastname: Goycochea-Robles
authors.forename: Luz Helena
authors.initials: LH
authors.lastname: Sanin
authors.forename: José
authors.initials: J
authors.lastname: Moreno-Montoya
authors.forename: José
authors.initials: J
authors.lastname: Alvarez-Nemegyei
authors.forename: Rubén
authors.initials: R
authors.lastname: Burgos-Vargas
authors.forename: Mario
authors.initials: M
authors.lastname: Garza-Elizondo
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Rodríguez-Amado
authors.forename: Marco A
authors.initials: MA
authors.lastname: Madariaga
authors.forename: Jorge A
authors.initials: JA
authors.lastname: Zamudio
authors.forename: Gisela Espinosa
authors.initials: GE
authors.lastname: Cuervo
authors.forename: Mario Humberto
authors.initials: MH
authors.lastname: Cardiel-Ríos
authors.forename: Ingris
authors.initials: I
authors.lastname: Peláez-Ballestas
mesh_terms: D018672:Community Health Planning; D003153:Community Health Services; D003430:Cross-Sectional Studies; D006306:Health Surveys; D006801:Humans; D007390:International Agencies; D016015:Logistic Models; D008403:Mass Screening; D008800:Mexico / Q000453:epidemiology; D010146:Pain / Q000145:classification* / Q000175:diagnosis; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012216:Rheumatic Diseases / Q000145:classification* / Q000175:diagnosis; D011795:Surveys and Questionnaires