title: Impact of chronic kidney disease among Korean adults with chronic obstructive pulmonary disease.
abstract: OBJECTIVE
  Chronic kidney disease (CKD) is an emerging issue in patients with chronic obstructive pulmonary disease (COPD). In COPD, loss of muscle mass is relatively common finding, and diagnosis of CKD should be based on measured or estimated GFR (Cavailles et al. Eur Respir Rev 22:454-475, 2013; Gosker et al. Am J Clin Nutr 71:1033-1047, 2000; Delanaye and Mariat Nat Rev Nephrol 9:513-522, 2013). We aimed to determine the prevalence and impact of CKD, defined by using chronic kidney disease epidemiology collaboration (CKD-EPI) equation, in COPD patients.
  
  
  METHODS
  This study analyzed data of 3393 adults 40 years of age or older who completed pulmonary function tests in the fifth Korea National Health and Nutritional Examination Survey 2012. Participants with normal lung function (NLF) and COPD were included. CKD was defined as an eGFR <60 mL/min/1.73 m2. Multivariate logistic regression analysis was performed to evaluate the relationship between CKD and COPD.
  
  
  RESULTS
  Among 3393 participants, 528 (15.6%) were classified as COPD. The prevalence values of participants with eGFR level ≥90, 60-90, and <60 mL/min/1.73 m2were 54.1, 43.6, and 2.2% in those with NLF and 39.8, 51.5, and 8.7% in those with COPD (p = 0.000). We analyzed the relationship between COPD and all factors that had a statistically significant association with COPD. The significant factors were older age, lower education, BMI, pulmonary tuberculosis, current bronchial asthma, smoking, and CKD.
  
  
  CONCLUSIONS
  In a Korean population ≥40 years old, the prevalence of participants with COPD is 15.6%. CKD is an independent risk factor for COPD. In addition to CKD, older age, lower education, BMI, pulmonary tuberculosis, current bronchial asthma, and smoking are significantly associated with COPD.
authors.affiliation: Department of Internal Medicine, Seoul Medical Center, 156 Sinnae-ro, Jungnang-gu, Seoul, 131-865, Korea. kmy008@hamnail.net.
authors.forename: Min Young
authors.initials: MY
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul Medical Center, 156 Sinnae-ro, Jungnang-gu, Seoul, 131-865, Korea.
authors.forename: Sungmin
authors.initials: S
authors.lastname: Boo
authors.affiliation: Department of Internal Medicine, Seoul Medical Center, 156 Sinnae-ro, Jungnang-gu, Seoul, 131-865, Korea.
authors.forename: Mijung
authors.initials: M
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, Seoul Medical Center, 156 Sinnae-ro, Jungnang-gu, Seoul, 131-865, Korea.
authors.forename: Jonghyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul Medical Center, 156 Sinnae-ro, Jungnang-gu, Seoul, 131-865, Korea.
authors.forename: Na Ree
authors.initials: NR
authors.lastname: Kang
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001249:Asthma / Q000453:epidemiology; D015992:Body Mass Index; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004522:Educational Status; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology*; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology* / Q000503:physiopathology; D056910:Republic of Korea; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology; D014397:Tuberculosis, Pulmonary / Q000453:epidemiology
keywords: Adult; Chronic kidney disease; Chronic obstructive pulmonary disease; Prevalence; Risk factor