Evaluation of Productive Cough and Outcomes in Stable COPD

Abstract

Background:

COPD is a heterogeneous disease characterized by chronic dyspnea, cough, sputum production, or exacerbations, but usually a combination of these symptoms. Studies have implied associations between chronic sputum production and FEV₁ decline in COPD. Thick mucus can lead to infection, the primary cause of exacerbations in COPD. We aimed to evaluate cough frequency and sputum production with associated disease presentation and needs in our outpatient COPD population.

Methods:

Retrospective analysis of 635 patients seen in the UC Davis COPD clinic between January 2019 and February 2023 was performed. Five-hundred and eight patients had documented cough and sputum production. Evaluation of cough frequencies, production, secretion amount, and viscosity reported by the patient along with assessment of smoking history, symptoms, exacerbations, GOLD classification and therapies were completed. This was deemed exempt by the UC Davis IRB (#2060632-1). Statistical analysis was performed with Chi-square and student t-test when appropriate.

Results:

Of the 508 patients with documented cough and sputum production, 47% (n = 237) reported frequent cough and 53% (n = 271) experienced infrequent cough. Ninety-five percent (n = 226) had a smoking history with a 39-pack year average in the frequent cough group and 89% (n = 241) smoking history and 38-pack year average in the infrequent group. Of the frequent coughers, 25% (n = 59) experienced productive cough with moderate to large amounts of thick secretions compared to the infrequent coughers at 5% (n = 13), P < .001. More of the frequent coughers required nebulized medications to manage their COPD at 73% (n = 43) vs. 38% (n = 5) in the infrequent cohort, P = .02. COPD assessment test (CAT) showed an average of 25.3 in frequent coughers and 20.7 in the infrequent coughers, P = .08. Little difference in GOLD class (P = .08), exacerbation history (P = .84), PIF (P = .76), inhaler technique (P = .22), or supplemental oxygen use ( P = .41) was noted.

Conclusions:

There was a statistically significant difference in cough production, sputum amount, and viscosity and requirement for nebulized medications. There was no difference in GOLD class, exacerbation history, PIF, inhaler technique, or oxygen use. While not statistically significant, the difference in CAT score between the groups was of clinical significance (MCID = 2).