Frequent Productive Cough Associated With Worse Outcomes in Asthma, COPD

Frequent productive cough was present in patients with asthma and/or chronic obstructive pulmonary disease (COPD) across all physician-assigned severity levels. According to study results published in Respiratory Medicine, the prevalence of frequent productive cough increased with higher disease severity, was linked with significant disease burden, and presented as an indicator for greater risk of adverse disease outcomes.

This study included patients with asthma and/or COPD who were enrolled in the NOVELTY study, a global, prospective, 3-year observational study that includes approximately 12,000 patients with asthma and/or COPD from clinical practices across 18 countries. Patients were split into groups by diagnosis—asthma, COPD, or asthma and COPD—and physician-assessed severity: mild, moderate, or severe. The total cohort comprised 7125 patients: 3754 (52.7%) had asthma, 887 (12.4%) had asthma and COPD, and 2484 (34.9%) had COPD.

The researchers defined frequent productive cough using 2 questions on the St George’s Respiratory Questionnaire (SGRQ): “Over the past 3 months, I have coughed…” and “Over the past 3 months, I have brought up phlegm (sputum)…” Responses ranged from 0 to 4, with 4 indicating more frequent coughing or bringing up phlegm. Patients were defined as having frequent productive cough if they scored a 3 or above on both items, meaning they had cough and sputum production most or several days during the week for the past 3 months.

Patients who scored a 3 or above for only one of the SGRQ questions were defined as having either frequent cough or frequent sputum production. Scoring a 3 or above on the SGRQ cough question and a 1 or below on the SGRQ sputum production question were defined as having frequent dry (nonproductive) cough.

Patient data from baseline and 1-year follow-up clinical study visits were evaluated using logistic regression. These data included physician-assigned diagnosis, physician-assessed severity, comorbidities, medications, biomarkers, spirometry, exacerbations, patient-reported questionnaires, and exposure history (exposure to pollutants).

Frequent productive cough was present in 31.3% of patients, frequent cough was present in 46.0%, and frequent sputum production was found in 40.4%. Frequent dry cough was found in 8.1%, and frequent cough or frequent sputum production was found in 55.2%.

Frequent productive cough was more common in patients with both asthma and COPD (38.8%). In comparing patients with just COPD or just asthma, frequent productive cough was more common in patients with COPD (38.1%) than patients with asthma (25.0%). This pattern was also observed for frequent cough and frequent sputum production.

The proportion of patients with frequent cough and/or sputum production increased as physician-assessed severity worsened. Frequent productive cough was also more common in current smokers (48.5%) than former smokers (30.6%) and never smokers (24.6%) and in non-smokers with COPD (40.9%) than in non-smokers with asthma (23.0%).

Patients with frequent productive cough reported symptomatic worsening more than patients without frequent productive cough, and their condition was associated with exposure to pollutants at home or work and with reduced postbronchodilator forced expiratory volume in 1 s. Further, patients with frequent productive cough reported at baseline were more likely than those who did not to have 1 or more exacerbations over the next year. These exacerbations included those resulting in hospital admission or requiring treatment with oral corticosteroids.

There were some limitations to this study. Comparisons between diagnostic groups may have been hindered by differences in patient age, as frequent productive cough symptoms increase with age. Also, the study did not include imaging data and researchers were unable to analyze patient sputum.

“Frequent productive cough represents an important indicator of adverse clinical outcomes across asthma and/or COPD,” the researchers concluded. “Research into the underlying pathologic mechanisms is required to support targeted therapy development.”

Reference

Hughes R, Rapsomaniki E, Janson C, et al; NOVELTY Study Investigators Frequent productive cough: symptom burden and future exacerbation risk among patients with asthma and/or COPD in the NOVELTY study. Respir Med. Published online June 20, 2022. doi:10.1016/j.rmed.2022.106921