title: Obesity Is Associated With Increased Morbidity in Moderate to Severe COPD.
abstract: BACKGROUND
  Obesity is prevalent in the United States; however, the impact of obesity on COPD morbidity is unclear. We hypothesized that obesity is associated with worse outcomes in COPD.
  
  
  METHODS
  We examined 3,631 participants from the multicenter prospective cohort study Genetic Epidemiology of COPD (COPDGene) who had spirometry-confirmed COPD, a postbronchodilator FEV1< 80% predicted, and a BMI ≥ 18.5 kg/m2. We conducted logistic and linear regression analyses to determine the association between COPD outcomes and obesity class, adjusting for relevant confounders. The referent for obesity classes included normal/overweight individuals (BMI range, 18.5-29.9 kg/m2).
  
  
  RESULTS
  Overall, 35% of participants were obese, with 21% class I (BMI range, 30-34.9 kg/m2), 9% class II (BMI range, 35-39.9 kg/m2), and 5% class III (BMI ≥ 40 kg/m2). The number of comorbidities increased with increasing obesity class (P < .001). Increasing obesity class was independently associated with worse respiratory-specific and general quality of life (QOL) (St. George's Respiratory Questionnaire score and Short Form-36 score version 2, respectively), reduced 6-min walk distance (6MWD), increased dyspnea (Modified Medical Research Council score ≥ 2), and greater odds of severe acute exacerbation of COPD (AECOPD). The associations between obesity and worse outcomes were independent of the presence of comorbidities, except in the case of SF-36 and severe exacerbations.
  
  
  CONCLUSIONS
  Obesity is prevalent among individuals with COPD and associated with worse COPD-related outcomes, ranging from QOL and dyspnea to 6MWD and severe AECOPD. These associations were strengthened when obesity was analyzed as a dose-dependent response. Obesity in patients with COPD may contribute to a worse COPD-related course.
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD. Electronic address: alamber5@jhmi.edu.
authors: Allison A
authors: AA
authors: Lambert
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: Nirupama
authors: N
authors: Putcha
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: M Bradley
authors: MB
authors: Drummond
authors: Department of Medicine, Division of Pulmonary and Critical Care, Baylor College of Medicine, Houston, TX.
authors: Aladin M
authors: AM
authors: Boriek
authors: Department of Medicine, Division of Pulmonary and Critical Care, Baylor College of Medicine, Houston, TX.
authors: Nicola A
authors: NA
authors: Hanania
authors: Department of Medicine, Division of Pulmonary and Critical Care, Temple University, Philadelphia, PA.
authors: Victor
authors: V
authors: Kim
authors: Department of Epidemiology, Colorado School of Public Health, University of Colorado, Aurora, CO.
authors: Gregory L
authors: GL
authors: Kinney
authors: Channing Division of Network Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
authors: Merry-Lynn N
authors: MN
authors: McDonald
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: Emily P
authors: EP
authors: Brigham
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: Robert A
authors: RA
authors: Wise
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: Meredith C
authors: MC
authors: McCormack
authors: Department of Medicine, Division of Pulmonary and Critical Care, Johns Hopkins University, Baltimore, MD.
authors: Nadia N
authors: NN
authors: Hansel
mesh_terms: D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D015897:Comorbidity; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000175:diagnosis / Q000453:epidemiology; D010807:Physical Endurance / Q000502:physiology; D015995:Prevalence; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D011788:Quality of Life; D012720:Severity of Illness Index; D013147:Spirometry / Q000379:methods; D013223:Statistics as Topic; D000067251:Symptom Flare Up; D014481:United States / Q000453:epidemiology
keywords: COPD; dose response; exacerbation; morbidity; obesity