title: Comorbidities in obstructive lung disease in Korea: data from the fourth and fifth Korean National Health and Nutrition Examination Survey.
abstract: BACKGROUND
  Comorbidities can occur frequently in patients with chronic obstructive pulmonary disease (COPD) and can influence mortality and morbidity independently. It is increasingly recognized that many patients with COPD have comorbidities that have a major impact on their quality of life and survival. Therefore, we investigated the prevalence of comorbidities in Korean COPD populations.
  
  
  METHODS
  We used data obtained in the 6 years of the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES) IV and V. Among 50,405 subjects, 16,151 subjects aged ≥40 years who performed spirometry adequately were included in this study. Airway obstruction was defined as forced expiratory volume in 1 second/forced vital capacity <0.7, and the Global Initiative For Chronic Obstructive Lung Disease stage was used to evaluate the severity of airway obstruction. Statistical analyses were performed using SAS 9.2.
  
  
  RESULTS
  Among the 16,151 subjects (43.2% male, 56.8% female; mean age: 57.1 years for men and 57.2 years for women), 13.1% had obstructive lung function; 11.3%, restrictive lung function; and 75.6%, normal lung function. Among individuals with obstructive lung function, 45.3%, 49.4%, and 5.3% had mild, moderate, and severe and very severe airflow limitation. The prevalence of hypertension, diabetes mellitus (DM), underweight, and hypertriglyceridemia was higher in the obstructive lung function group than in the normal lung function group (49.6% vs 35.2%; 16.8% vs 10.5%; 3.3% vs 1.3%; 19.7% vs 17.0%). According to the severity of airway obstruction, hypertension and underweight were more common as severity increased, although the prevalence of DM and hypertriglyceridemia was lower in subjects with severe airway obstruction. The prevalence of hypercholesterolemia, overweight, and osteoarthritis was lower in the obstructive lung function group, especially in the severe airway obstruction groups.
  
  
  CONCLUSIONS
  Overall, our analysis is similar to research that was conducted earlier. Our study showed that hypertension and underweight are common comorbidities in COPD patients, and are higher as the severity of airflow obstruction increased in both men and women. DM, hypertriglyceridemia, and low high-density lipoprotein cholesterol are more common in subjects with airway obstruction, although their incidence is lower in the severe group.
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Hee Jin
authors: HJ
authors: Park
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Ah Young
authors: AY
authors: Leem
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Sang Hoon
authors: SH
authors: Lee
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Ju Han
authors: JH
authors: Song
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Moo Suk
authors: MS
authors: Park
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Young Sam
authors: YS
authors: Kim
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Se Kyu
authors: SK
authors: Kim
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Joon
authors: J
authors: Chang
authors: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Severance Hospital, Institute of Chest Disease, Yonsei University College of Medicine, Seoul, South Korea.
authors: Kyung Soo
authors: KS
authors: Chung
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000175:diagnosis / Q000453:epidemiology*; D050171:Dyslipidemias / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D006973:Hypertension / Q000175:diagnosis / Q000453:epidemiology*; D015994:Incidence; D008168:Lung / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D013147:Spirometry; D011795:Surveys and Questionnaires; D013851:Thinness / Q000175:diagnosis / Q000453:epidemiology*; D013997:Time Factors; D014797:Vital Capacity
keywords: chronic obstructive pulmonary disease; comorbidity; hypertension; underweight