Abstract
BackgroundExacerbations are critical events in chronic pulmonary obstructive disease (COPD). The frequency of COPD exacerbations is associated with the prognosis, including mortality, but no useful biomarker has been established.MethodsThe present retrospective study investigated 481 COPD patients. Clinical features in the stable period were compared between patients who experienced severe exacerbation (n = 88, 18.3%) and those who never experienced severe exacerbation (n = 393, 81.7%). In the patients who experienced exacerbations, clinical features were also compared between frequent exacerbators (exacerbation rate ≥ 2 times/year, n = 27, 30.7%) and infrequent exacerbators (1 time/year, n = 61, 69.3%).ResultsCompared to COPD patients who never experienced exacerbations, body mass index (BMI), serum albumin, and pulmonary functions were significantly lower, and the cardiovascular disease comorbidity rate, COPD assessment test score, modified Medical Research Council dyspnea scale, and use of long-term oxygen therapy, long-acting β2 adrenergic agonist therapy, inhaled corticosteroid therapy, and macrolide therapy were significantly higher in COPD patients with exacerbations (all p < 0.01). In patients who experienced exacerbations, frequent exacerbators had significantly lower % forced expiratory volume in 1.0 s and a higher risk of critical exacerbations, percentage of blood eosinophils, history of mechanical ventilation use, and use of long-term oxygen therapy and of macrolide therapy than infrequent exacerbators (all p < 0.01). On multivariate analysis, the percentage of blood eosinophils was the parameter most correlated with exacerbation frequency (β value [95% confidence interval] 1.45 [1.12–1.88], p < 0.01).ConclusionBlood eosinophil in the stable period is the factor most correlated with the frequency of severe exacerbations.Trial registration: The patients in this study was registered retrospectively
Highlights
Exacerbations are critical events in chronic pulmonary obstructive disease (COPD)
To assess the correlations between the maximum annual exacerbation rate and clinical factors, patients’ characteristics, COPD assessment test (CAT) score, modified Medical Research Council dyspnea scale, laboratory data, pulmonary function test results, transtricuspid pressure gradient (TRPG) on echocardiography, and treatment regimens were evaluated in the stable phase which was defined as no use of oral corticosteroids or antibiotics, no unscheduled doctor’s visit, or no hospitalization due to exacerbation of COPD in the past 4 weeks
There were no significant differences in age, sex, height, and smoking history, but weight and the body mass index were significantly lower in patients with exacerbations than in those without exacerbations (p < 0.01, respectively)
Summary
The frequency of COPD exacerbations is associated with the prognosis, including mortality, but no useful biomarker has been established. Chronic pulmonary obstructive disease (COPD) is a common respiratory disease, with a reported global prevalence of 251 million cases, and it is an important life-threatening lung disease that is predicted to become the third leading cause of death worldwide by 2030 [1]. COPD, triggered by respiratory infections with bacteria and viruses and other factors such as pollution [2, 3] It is associated with worsening of mortality, lung function, and health-related quality of life. In a prospective cohort of 304 men with COPD followed-up for 5 years, exacerbations requiring hospitalization showed an independent negative impact on patient prognosis [8]. To predict and prevent a worse clinical course in COPD patients, a more precise biomarker for frequent and severe exacerbations is necessary
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