Airway obstruction in systolic heart failure--COPD or congestion?

BACKGROUND: The diagnosis of chronic obstructive pulmonary disease (COPD) in patients with systolic heart failure (SHF) is challenging because symptoms of both conditions overlap. We aimed to estimate the prevalence, correlates and prognostic impact of true COPD in patients with SHF.
METHODS: To diagnose COPD under stable conditions according to the guidelines, pulmonary function testing (PFT) was performed in 619 patients six months after hospitalization for congestive SHF. In 272 patients, PFT had been also performed prior to discharge.
RESULTS: In the total cohort, COPD was reported in 23% (144/619). PFT under stable conditions revealed that COPD was absent in 73% (449/619), unconfirmed in 18% (112/619), and proven in 9% (58/619). In 272 patients with serial PFT, initial airway obstruction was found in 19% (51/272) but had resolved in 47% of those (24/51) after six months. Initial hyperinflation detected by bodyplethysmography strongly predicted proven COPD six months later: odds ratio for elevated intrathoracic gas volume 12.8, 95% confidence interval (CI) 2.5-65.9; p=0.002. After a median follow-up of 34 months, 27% of the total cohort (165/619) had died. Only proven COPD was associated with an increased mortality risk after adjustment for age, sex, NYHA functional class, ejection fraction, atrial fibrillation, smoking, renal dysfunction and diabetes: hazard ratio 1.64, 95%CI 1.03-2.63; p=0.039.
CONCLUSIONS: Airway obstruction is a dynamic phenomenon in SHF. Therefore, a valid diagnosis of COPD in SHF demands serial PFT under stable conditions with special attention to hyperinflation. COPD proven by PFT is associated with an increased all-cause mortality risk.