Nonobstructive chronic bronchitis tied to adverse respiratory health outcomes
Patients with nonobstructive chronic bronchitis appear to have a higher risk for adverse respiratory health outcomes, according to a study published in JAMA Internal Medicine.
Specifically, the researchers found that after adjustment for anthropometric, sociodemographic and smoking-related factors, nonobstructive chronic bronchitis was associated with an increased risk for chronic lower respiratory disease-related hospitalization or death among both people who had ever smoked (HR = 2.2; 95% CI, 1.7-2.7) and among people who had never smoked (HR = 3.1; 95% CI, 2.1-4.5).
Additionally, nonobstructive chronic bronchitis was also linked to higher rates of death related to respiratory disease (HR =2; 95% CI, 1.1-3.8) or any cause (HR = 1.5; 95% CI, 1.3-1.8) and accelerated decreases in FEV1 and FVC in ever-smokers. However, there appeared to be no association between the condition and mortality or FEV1 and FVC decline in those who never smoked.
Nonobstructive chronic bronchitis was also not associated with FEV1:FVC or incident airflow obstruction, according to the data.
Results were comparable when evaluating the component symptoms of nonobstructive chronic bronchitis. The presence of at least one symptom — chronic cough or phlegm — was common in both ever-smokers (11%) and never-smokers (6.7%). Ever-smokers with at least one symptom demonstrated accelerated declines in FEV1 and FVC, had an increased risk for chronic lower respiratory disease-related hospitalization and death (HR = 1.7; 95% CI, 1.5-2) and increased mortality related to respiratory disease (HR = 1.8; 95% CI, 1.2-2.6) or any cause (HR = 1.2; 95% CI, 1.1-1.3). Consistent with the overall study findings, never-smokers with at least one symptom had an increased risk for chronic lower respiratory disease-related hospitalization or death (HR = 1.9; 95% CI, 1.5-2.4) but not an increased risk for respiratory-related or all-cause mortality.
The study included data on 22,325 adults enrolled from 1971 to 2007 and followed through 2018 from five cohorts: the ARIC study, the CARDIA study, Cardiovascular Health Study, the Framingham offspring cohort and the MESA study. The mean age was 53 years, 58.2% were women and 65.9% were white. Among the overall cohort, the researchers assessed data on 11,082 ever-smokers with 99,869 person-years of follow-up and 11,243 never-smokers with 120,004 person-years of follow-up. Patients did not have initial airflow obstruction or asthma at baseline.
“The current study is important because it showed that nonobstructive chronic bronchitis may not be just a curious phenomenon. Instead, it may be associated with an accelerated loss of lung function over time, chronic or recurrent lower respiratory tract symptoms, and associated morbidity and mortality,” Prescott G. Woodruff, MD, and Stephen C. Lazarus, MD, both from the Cardiovascular Research Institute and the division of pulmonary, critical care, sleep and allergy in the department of medicine at the University of California, San Francisco, wrote in an invited commentary. “Clinicians and investigators are faced with uncertainty about how to manage individual patients who present with chronic bronchitis and/or COPD-like symptoms and normal spirometric measurements. Studies are underway or planned to look at this prospectively, and future studies of COPD interventions should include patients with symptoms (eg, cough, sputum, dyspnea) but normal spirometric results.” – by Melissa Foster
Disclosures: Balte reports no relevant financial disclosures. Please see the full study for all other authors’ relevant financial disclosures. Lazarus reports he has received grants from the American Lung Association-Airway Clinical Research Networks, the Department of Defense Beta-Blockers in COPD Network, the NIH/National Heart, Lung, and Blood Institute (NHLBI) COPD Clinical Research Network and the NIH/NHLBI Subpopulations and Intermediate Outcomes Measures in COPD (SPIROMICS) Network. Woodruff reports he has received grants from the NIH.