Chronic Cough and Phlegm in Subjects Undergoing Comprehensive Health Examination in Japan – Survey of Chronic Obstructive Pulmonary Disease Patients Epidemiology in Japan (SCOPE-J)

Abstract

Purpose

The purpose of this study was to estimate the prevalence of subjects with chronic cough and phlegm and describe their characteristics including the presence or absence of airflow limitation among the general population in Japan.

Subjects and Methods

This was an observational cross-sectional survey targeting multiple regions of Japan. Subjects aged 40 years or above who were undergoing comprehensive health examination were recruited. The existence of chronic cough and phlegm, airflow limitation, and treatment for respiratory diseases were examined. Chronic cough and phlegm were defined as having both symptoms for at least 3 months of the year and for at least 2 consecutive years, or as receiving any treatment for chronic bronchitis at the time of recruitment. Airflow limitation was defined as forced expiratory volume in 1 s/forced vital capacity (FEV1/FVC) less than 0.7.

Results

In a total of 22,293 subjects, 380 subjects (1.7%) had chronic cough and phlegm. Among these 380 subjects, 21.8% received treatment for a respiratory disease, and 11.6% had airflow limitation. Compared to subjects without both chronic cough and phlegm but with airflow limitation, subjects with chronic cough and phlegm without airflow limitation were younger, more likely to be current smokers (39.6%), and had higher total scores on a chronic obstructive pulmonary disease (COPD) assessment test (CAT). Scores of CAT questions 1–4 (cough, phlegm, chest tightness, breathlessness, respectively) were higher in subjects with chronic cough and phlegm regardless of airflow limitation.

Conclusion

This study demonstrated that subjects identified to have chronic cough and phlegm in comprehensive health examination settings were symptomatic, while most of them did not receive any treatment for respiratory diseases and did not have airflow limitation. Screening subjects for chronic cough and phlegm in a comprehensive health examination followed by a detailed examination of screened subjects could be an effective approach for better management of chronic cough and phlegm. Smoking cessation should be included in the management, in consideration that around 40% of subjects with chronic cough and phlegm were current smokers.

Keywords:

• respiratory disease
• chronic bronchitis
• spirometry
• lung function
• general population
• health checkup

Acknowledgments

The authors are grateful to the examinees who participated in this survey and the staff of the medical institutions who contributed to this survey. The following investigators took part in data collection of this survey: Dr. Takeshi Nawa (Hitachi General Hospital, Hitachi Ltd.), Dr. Kazuhiro Gotou (Health Park Clinic Kurosawa), Dr. Takashi Nakagawa (Omiya City Clinic), Dr. Koji Yamashita (Yotsukaido Tokushukai Hospital), Dr. Tatsuo Morikawa (Tokyo-Nishi Tokushukai Hospital), Dr. Takayuki Kashiwabara (JA Shizuoka Kohseiren Enshu Hospital), Dr. Tatsuya Shiraki (Matsubara Tokushukai Hospital), Dr. Ryo Kobayashi (Bell Clinic), Dr. Hiroshi Sonobe (Chugoku Central Hospital), Dr. Toshiki Fukui (Center for Preventive Medical Treatment, Olive Takamatsu Medical Clinic), Dr. Tokuji Motoki (Kochi Kenshin Clinic), Dr. Yasuhiro Ogata, Dr. Noritaka Higashi (Japanese Red Cross Kumamoto Health Care Center), Dr. Junko Aburaya (Koga Kenshin Center, Koga Ekimae Clinic), and Dr. Koki Ido (Osumi Kanoya Hospital).

Abbreviations

AL, airflow limitation; BMI, body mass index; CAT, chronic obstructive pulmonary disease assessment test; CRP, c-reactive protein; COPD, chronic obstructive pulmonary disease; FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; SD, standard deviation; SCOPE-J, survey of chronic obstructive pulmonary disease patients epidemiology in Japan.

Author Contributions

Conception or design: HO, TK, TS; data acquisition: NH, TN, TF; analysis or interpretation: all authors. Drafting the manuscript: HO, TK, TS; revising the manuscript critically for important intellectual content: all authors. All authors approved the final version for publication and agreed to be accountable for all aspects of the work.

Disclosure

GlaxoSmithKline (GSK) was the funding source and was involved in all stages of this study (WEUSKOP6290). GSK also funded all costs associated with the publishing of the present manuscript. HO, NH, TN, and TF received funding for this study from GSK. TK is an employee of GSK and owns stock of the company. TK received pay for a part-time lecture from Shiga University of Medical Science. TS is an employee of GSK. The authors report no other conflicts of interest in this work.