Spirometry quality in patients with COPD exacerbation, related to the "frequent exacerbator" phenotype

Aim: To assess the quality of spirometry sessions in patients with COPD exacerbation; to compare the spirometry quality in patients with frequent exacerbations (two or more in the previous year) and in patients without exacerbations. Subjects and methods: Consecutive COPD patients with moderate infectious exacerbation were evaluated at presentation. The quality of spirometry (ATS/ERS 2005: at least 3 acceptable curves with repeatable values for FVC and FEV1) and the time needed to obtain a spirometry session were evaluated and compared to the spirometries obtained 3-6 months previously in a stable period. Results: 80 COPD patients were evaluated, mean age 63 years, 60 males. Although all patients had valid spirometry sessions in the stable period, 12 subjects (15%) could not obtain a valid session during exacerbation due to cough, shortness of breath and/or fatigue. More efforts were necessary to obtain a spirometry session during exacerbation (4.6±1.2 efforts) compared to the stable period (3.8±0.9 efforts, p=0.001). The time needed to obtain a spirometry session was significantly higher in exacerbation (5.7±1.4 minutes) compared to the stable period (4.8±1.6, p=0.001). Frequent exacerbators (33 patients, 41%) had similar spirometry quality in exacerbation and in the stable period, and similar amount of time needed to perform the spirometries compared to the patients with no exacerbations (p>0.05). Conclusions: Lower spirometry quality and higher time needed to obtain a spirometry session were seen in exacerbation compared to a stable COPD period. Similar spirometry quality was seen in patients with frequent exacerbations as in patients without exacerbations in the previous year.