TY - JOUR T1 - COPD prevalence in a random population survey: a matter of definition JF - European Respiratory Journal JO - Eur Respir J SP - 232 LP - 239 DO - 10.1183/09031936.00157906 VL - 30 IS - 2 AU - P. Shirtcliffe AU - M. Weatherall AU - S. Marsh AU - J. Travers AU - A. Hansell AU - A. McNaughton AU - S. Aldington AU - H. Muellerova AU - R. Beasley Y1 - 2007/08/01 UR - http://erj.ersjournals.com/content/30/2/232.abstract N2 - A recent American Thoracic Society and European Respiratory Society joint Task Force report recommends using a lower limit of normal (LLN) of forced expiratory volume in one second/forced vital capacity as opposed to a fixed ratio of <0.7 to diagnose airflow obstruction, in order to reduce false positive diagnoses of chronic obstructive pulmonary disease (COPD) as defined by the Global Initiative for Obstructive Lung Disease (GOLD). To date, there is no reliable spirometry-based prevalence data for COPD in New Zealand and the effect of different definitions of airflow obstruction based on post-bronchodilator spirometry is not known. Detailed written questionnaires, full pulmonary function tests (including pre- and post-bronchodilator flow–volume loops) and atopy testing were completed in 749 subjects recruited from a random population sample. The GOLD-defined, age-adjusted prevalence (95% confidence interval) for adults aged ≥40 yrs was 14.2 (11.0–17.0)% compared with an LLN-defined, age-adjusted, post-bronchodilator prevalence in the same group of 9.0 (6.7–11.3)%. The prevalence of chronic obstructive pulmonary disease varied markedly depending on the definition used. Further research using longitudinal rather than cross-sectional data will help decide the preferred approach in chronic obstructive pulmonary disease prevalence surveys. ER -