Prevalence of chronic obstructive pulmonary disease in Korea: the fourth Korean National Health and Nutrition Examination Survey, 2008.

BACKGROUND AND OBJECTIVE: Because the mortality and social burden associated with COPD is increasing, repeated surveys of the prevalence of COPD have been used to assess risk factors, detect potential patients, and establish early diagnoses and management protocols. We report the prevalence of spirometrically detected COPD in Korea in 2008, using data from the fourth Korean National Health and Nutrition Survey. METHODS: Using nationwide stratified random sampling, based on the Korean Statistical Office census, 6840 subjects aged ≥19years underwent spirometry, which was performed by four trained technicians, during 2008. The place of residence, levels of education and income and smoking status, as well as other results from a COPD survey questionnaire were also assessed. RESULTS: Airflow obstruction (FEV(1) /FVC<0.7) was detected in 8.8% of subjects aged ≥19years (11.6% of men and 5.9% of women) and COPD was detected in 13.4% of subjects aged ≥40years (19.4% of men and 7.9% of women). Of the 6840 subjects, 27.3% were current smokers and 17.2% were former smokers, and the prevalence of COPD was higher in current and former smokers than in never smokers. Approximately 94% of patients with COPD had mild-to-moderate disease, without apparent symptoms; only 2.4% had been diagnosed by a physician and only 2.1% of patients had been treated. The independent risk factors for COPD were smoking, advanced age and male gender. CONCLUSIONS: Although the prevalence of COPD in Korea is high, the disease is underdiagnosed and most COPD patients are under-treated.

Association between CRHR1 polymorphism and improved lung function in response to inhaled corticosteroid in patients with COPD.

BACKGROUND AND OBJECTIVE: Inhaled corticosteroids are used to treat COPD and asthma. An association between sequence variants in the corticotrophin-releasing hormone receptor 1 (CRHR1) gene and improved lung function in asthmatics treated with inhaled corticosteroids was reported recently. This study investigated the association between the change in lung function in response to inhaled corticosteroids and single-nucleotide CRHR1 polymorphisms in patients with COPD. METHODS: COPD patients (n = 87) with a positive smoking history were recruited from the pulmonary clinics of 11 hospitals in Korea. Patients were treated with fluticasone propionate and salmeterol for 12 weeks and lung function was measured at baseline and after the 12-week treatment. Eighty-four of the 87 subjects were successfully genotyped. RESULTS: Seventy-one patients with the wild-type GG genotype and 13 patients with the heterozygous GT genotype in rs242 941 were evaluated. After 12-week treatment, the change in FEV(1) was significantly higher in patients with wild-type GG genotype (6.0 +/- 0.8% of predicted FEV(1)) than in GT heterozygotes (-0.8 +/- 1.8, P = 0.003). CONCLUSIONS: Improved FEV(1) following inhaled corticosteroid and a long-acting beta2-agonist was associated with CRHR1 genetic polymorphism in patients with COPD.