Validation of self-reported chronic obstructive pulmonary disease in a cohort study of nurses.
Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death, and its prevalence is increasing; however, few strategies are available for disease prevention or modification besides smoking interventions. To facilitate examination of modifiable risk factors for COPD in the Nurses' Health Study, the authors validated a questionnaire-based definition of COPD in a subset of this US cohort. Participants were surveyed biennially about lifestyle factors, including smoking, since 1976 and physician diagnosis of COPD since 1988. Self-reported cases were defined as reporting COPD on both the original (1988-1996) and supplemental (1998) questionnaires. The authors requested medical records for a 10% random sample of 2,790 cases and reviewed these records in a systematic, blinded fashion. Validated cases required obstructive spirometry, emphysema on chest radiograph or computed tomography, or physician diagnosis. COPD was confirmed for 78% of 273 cases. Spirometry or radiographic results were available for 84%; when available, mean forced expiratory volume in 1 second was 51% predicted (standard deviation, 19). Applying these results to a hypothetical cohort, the authors estimated the degree to which disease misclassification biases relative risks toward the null value, confirming that questionnaire-based COPD research should focus on minimizing false positives rather than false negatives. In conclusion, COPD can be studied in large, questionnaire-based cohorts of health professionals.
Barr
R Graham
RG
Channing Laboratory, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Herbstman
Julie
J
Speizer
Frank E
FE
Camargo
Carlos A
CA
D000328:Adult; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008499:Medical Records / Q000706:statistics & numerical data*; D008875:Middle Aged; D009726:Nurses / Q000706:statistics & numerical data*; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D012680:Sensitivity and Specificity; D016540:Smoking Cessation; D013147:Spirometry; D011795:Surveys and Questionnaires; D015898:Tomography Scanners, X-Ray Computed; D014481:United States / Q000453:epidemiology