Undetected chronic obstructive pulmonary disease and asthma in people over 50 years with persistent cough.

Background Chronic obstructive pulmonary disease (COPD) and asthma are underdiagnosed in primary care. Aim To determine how often COPD or asthma are present in middle-aged and older patients who consult their GP for persistent cough. Design of study A cross-sectional study in 353 patients older than 50 years, visiting their GP for persistent cough and not known to have COPD or asthma. Setting General practice in the Netherlands. Method All participants underwent extensive diagnostic workup, including symptoms, signs, spirometry, and body plethysmography. All results were studied by an expert panel to diagnose or exclude COPD and/or asthma. The reproducibility of the panel diagnosis was assessed by calculation of Cohen's K statistic in a sample of 41 participants. Results Of the 353 participants, 102 (29%, 95% confidence interval [CI] = 24 to 34%) were diagnosed with COPD. In 14 of these 102 participants, both COPD and asthma were diagnosed (4%, 95% CI = 2 to 7%). Asthma (without COPD) was diagnosed in 23 (7%, 95% CI = 4 to 10%) participants. Mean duration of cough was 93 days (median 40 days). The reproducibility of the expert panel was good (Cohen's K = 0.90). Conclusion In patients aged over 50 years who consult their GP for persistent cough, undetected COPE) or asthma is frequently present. [ABSTRACT FROM AUTHOR]