Differential changes in quality of life components over 5 years in chronic obstructive pulmonary disease patients.
BACKGROUND
The aim of the study was to examine the longitudinal change in quality of life components of patients with chronic obstructive pulmonary disease (COPD).


METHODS
In the Hokkaido COPD Cohort Study, 261 subjects were appropriately treated and followed over 5 years with a 74% follow-up rate at the end. The longitudinal changes in St George's Respiratory Questionnaire (SGRQ) scores were annually evaluated with forced expiratory volume in 1 second (FEV1). The subjects were classified into the rapid decliners, slow decliners, and sustainers based on ΔFEV1/year.


RESULTS
The activity component of SGRQ generally deteriorated over time, and its annual decline was the greatest in the rapid decliners (<25th percentile). In contrast, the symptom component improved significantly year by year in the sustainers (>75 percentile), and it did not deteriorate even in the rapid decliners. Of the baseline data, predictors for worsening of the activity component were older age and lower body mass index. Larger reversibility was related to symptom component improvement. Of the follow-up data, ΔFEV1/year was the best predictor for worsening of the components of SGRQ. Continuous smoking was another factor for worsening of the activity component. For the symptom component, a history of exacerbation by admission definition was the determinant of its deterioration, whereas use of beta agonists was related to improvement.


CONCLUSIONS
The longitudinal changes of quality of life and their determinants are markedly different and independent between its components. The activity component of SGRQ generally deteriorated over years, while the symptom component rather improved in some patients with COPD under appropriate treatment.
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Katsura
K
Nagai
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Hironi
H
Makita
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Masaru
M
Suzuki
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Kaoruko
K
Shimizu
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Satoshi
S
Konno
Department of Biostatistics, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Yoichi M
YM
Ito
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Masaharu
M
Nishimura
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D000367:Age Factors; D015992:Body Mass Index; D001993:Bronchodilator Agents / Q000627:therapeutic use; D018450:Disease Progression; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007564:Japan; D008137:Longitudinal Studies; D008168:Lung / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology*; D011788:Quality of Life; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D011795:Surveys and Questionnaires; D013997:Time Factors; D016896:Treatment Outcome
D000318:Adrenergic beta-Agonists; D001993:Bronchodilator Agents
SGRQ; annual change; exacerbation; forced expiratory volume in 1 second; smoking