Spirometry for patients in hospital and one month after admission with an acute exacerbation of COPD

Harry Rea¹, Timothy Kenealy¹, Jacqui Adair¹, Elizabeth Robinson², Nicolette Sheridan^3
1Section of Integrated Care, South Auckland Clinical School, University of Auckland, ²Biostatistics and Epidemiology, School of Population Health, University of Auckland, ³Section of Integrated Care, South Auckland Clinical School and School of Nursing, University of Auckland, Auckland, New Zealand

Aim: To assess whether spirometry done in hospital during an admission for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is clinically useful for long-term management.
Methods: Patients admitted to hospital with a clinical diagnosis of AECOPD had spirometry post-bronchodilator at discharge and approximately 4 weeks later.
Results: Spirometry was achieved in less than half of those considered to have AECOPD. Of 49 patients who had spirometry on both occasions, 41 met the GOLD criteria for COPD at discharge and 39 of these met the criteria at 1 month. For the 41, spirometry was not statistically different between discharge and 1 month but often crossed arbitrary boundaries for classification of severity based on FEV₁. The eight who did not meet GOLD criteria at discharge were either misclassified due to comorbidities that reduce FVC, or they did not have COPD as a cause of their hospital admission.
Conclusion: Spirometry done in hospital at the time of AECOP is useful in patients with a high pre-test probability of moderate-to-severe COPD. Small changes in spirometry at 1 month could place them up or down one grade of severity. Spirometry at discharge may be useful to detect those who warrant further investigation.

Keywords: classification of COPD, spirometry, acute exacerbation of COPD, primary care, cohort study