Associations of lifelong cigarette consumption and hypertension with airflow limitation in primary care clinic outpatients in Japan

BackgroundUnderdiagnosis is a critical problem in the management of chronic obstructive pulmonary disease (COPD). It is important to screen patients at risk for COPD among those with lifestyle-related diseases such as hypertension, diabetes mellitus, and dyslipidemia, since these diseases promote the development of cardiovascular diseases closely associated with increased COPD mortality.MethodsThirteen primary care clinics in a suburb of Tokyo participated in the current study. A total of 950 patients from these clinics were enrolled in the study between 2010 and 2012; the patients ranged in age from 40 to 79 years, and they had no diagnosed respiratory diseases at the time of enrollment. Patients fulfilling the selection criteria were recruited to undergo spirometry and then completed a self-report questionnaire about comorbid diseases and smoking habits. Spirometry was performed 15 min after inhalation of 200 μg of salbutamol sulfate.ResultsThe prevalence of airflow limitation was 12.7% in the 950 primary care clinic patients. Lifelong cigarette consumption was the most significant risk factor for airflow limitation, e.g., patients who smoked 60 pack-years or more had a 40% likelihood of airflow limitation. Among common lifestyle-related diseases, hypertension was associated with the severity of airflow limitation (p=0.03), whereas dyslipidemia appeared to be inversely correlated with the severity of airflow limitation (p=0.004) on multiple regression analysis including lifelong cigarette consumption as a factor.ConclusionsUndiagnosed airflow limitation was detected in 12.7% of outpatients at the primary care clinics. Since most patients with lifestyle-related diseases are treated by primary care physicians, it is essential for the physicians to obtain an accurate history of smoking and comorbid diseases to screen patients for COPD.