Related Experiment Video
Updated: Oct 3, 2025
Generation of a Chronic Obstructive Pulmonary Disease Model in Mice by Repeated Ozone Exposure
Published on: August 25, 2017
Association of Nonobstructive Chronic Bronchitis With All-Cause Mortality: A Systematic Literature Review and
Spyridon Fortis1, Zacariah K Shannon2, Crystal J Garcia2
1Center for Access & Delivery Research & Evaluation, Iowa City VA Health Care System, Iowa City, IA; Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA; Department of Epidemiology, College of Public Health, Iowa City, IA.
Background:
The effect of nonobstructive chronic bronchitis (CB) on mortality is unclear.
Research Question:
Is nonobstructive CB associated with increased all-cause mortality?
Study Design And Methods:
We conducted a systematic literature review and meta-analysis to assess the association of nonobstructive CB and all-cause mortality. We searched for articles that included both CB and mortality in the title, abstract, or both in PubMed and EMBASE. We excluded studies in which participants demonstrated obstructive spirometry findings and studies in which CB and mortality were not defined. We used the Newcastle-Ottawa Quality Assessment Scale to assess study quality. We pooled adjusted hazard ratios (HRs) using the random effects model and inverse variance weighting. We conducted stratified analysis by the definition of CB and smoking status. We used Cochran's Q and I2 to assess for heterogeneity. We assessed publication bias by visual inspection of a funnel plot.
Results:
Of 5,014 titles identified, eight fulfilled the inclusion and exclusion criteria. Overall nonobstructive CB was associated with all-cause mortality (HR, 1.37; 95% CI, 1.26-1.50) with no statistically significant heterogeneity (P = .14; I2 = 29%). Nonobstructive CB was associated with increased mortality in studies that defined CB as any respiratory symptoms (broad definition; HR, 1.28; 95% CI, 1.10-1.48; I2 = 0%) as well as in the rest of the studies (HR, 1.40; 95% CI, 1.26-1.56; I2 = 37%). Nonobstructive CB was associated with increased mortality in ever smokers (HR, 1.49; 95% CI, 1.35-1.64; I2 = 0%), but was not associated with increased mortality in never smokers (HR, 1.22; 95% CI, 0.90-1.66), and moderate heterogeneity was found (P = .10; I2 = 49%). The funnel plot did not indicate evidence of a publication bias because it showed symmetrical distribution of studies.
Interpretation:
Nonobstructive CB is associated with increased all-cause mortality, and this association seems to be present only in current and former smokers. Further research should investigate whether this high-risk population may benefit from early therapeutic intervention.
Trial Registry:
PROSPERO; No.: CRD42021253596; URL: www.crd.york.ac.uk/prospero.
More Related Videos
05:19Author Spotlight: An Effective Traditional Chinese Medicinal Treatment for Chronic Obstructive Pulmonary Disease with Abdominal Distension
Published on: September 1, 2023
05:34Author Spotlight: Utilizing Traditional Chinese Acupuncture of the Ear to Improve Sleep Disorders
Published on: August 18, 2023
Related Concept Videos
01:22Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...
01:20Chronic Obstructive Pulmonary Disease-II: Pathophysiology
Chronic Inflammation
01:20Chronic Obstructive Pulmonary Disease-I: Introduction
01:27Chronic Obstructive Pulmonary Disease-IV: Assessement and Diagnostic Studies
Medical History
01:25Chronic Obstructive Pulmonary Disease-III: Symptoms and Complications.
Symptoms of COPD can be classified as primary or systemic. Primary symptoms relate to reduced airflow, while systemic or extrapulmonary symptoms relate to COPD's broader impact on the body.
Primary Symptoms of COPD:
01:20COPD: Pathogenesis and Clinical Features
The primary cause for the onset of COPD is cigarette smoking and exposure to air pollution. These hazardous factors initiate a chain reaction within the lungs, resulting in chronic inflammation, damage to the airways, and a...