title: Impact of mild exacerbation on COPD symptoms in a Japanese cohort.
abstract: BACKGROUND
  Patients with COPD might not report mild exacerbation. The frequency, risk factors, and impact of mild exacerbation on COPD status are unknown.
  
  
  OBJECTIVE
  The present study was performed to compare features between mild exacerbation and moderate or severe exacerbation in Japanese patients with COPD.
  
  
  METHODS
  An observational COPD cohort was designed at Keio University and affiliated hospitals to prospectively investigate the management of COPD comorbidities. This study analyzes data only from patients with COPD who had completed annual examinations and questionnaires over a period of 2 years (n=311).
  
  
  RESULTS
  Among 59 patients with mild exacerbations during the first year, 32.2% also experienced only mild exacerbations in the second year. Among 60 patients with moderate or severe exacerbations during the first year, 40% also had the same severity of exacerbation during the second year. Findings of the COPD assessment test and the symptom component of the St George's Respiratory Questionnaire at steady state were worse in patients with mild exacerbations than in those who were exacerbation free during the 2-year study period, although the severity of the ratio of predicted forced expiratory volume in 1 second did not differ between them. Severe airflow limitation (the ratio of predicted forced expiratory volume in 1 second <50%) and experience of mild exacerbations independently advanced the likelihood of an elevated COPD assessment test score to ≥2 per year.
  
  
  CONCLUSIONS
  The severity of COPD exacerbation seemed to be temporally stable over 2 years, and even mild exacerbations adversely impacted the health-related quality of life of patients with COPD.
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Sato
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Shotaro
authors.initials: S
authors.lastname: Chubachi
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Mizuha
authors.initials: M
authors.lastname: Haraguchi
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Naofumi
authors.initials: N
authors.lastname: Kameyama
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tsutsumi
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Saeko
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan; Department of Respiratory Medicine, Saitama Medical University, Saitama, Japan.
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Nakamura
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Tokai University School of Medicine, Kanagawa, Japan.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Asano
authors.affiliation: Division of Pulmonary Medicine, Department of Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Betsuyaku
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy; D011788:Quality of Life; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D013997:Time Factors
keywords: COPD; COPD exacerbation; chronic emphysema; comorbidity; quality of life