Obesity Is Associated With Increased Morbidity in Moderate to Severe COPD

Chest. 2017 Jan;151(1):68-77. doi: 10.1016/j.chest.2016.08.1432. Epub 2016 Aug 25.


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.

Keywords: COPD; dose response; exacerbation; morbidity; obesity.

Publication types

  • Multicenter Study

MeSH terms

  • Aged
  • Body Mass Index
  • Cohort Studies
  • Comorbidity
  • Female
  • Forced Expiratory Volume
  • Humans
  • Male
  • Middle Aged
  • Obesity* / diagnosis
  • Obesity* / epidemiology
  • Physical Endurance / physiology
  • Prevalence
  • Prospective Studies
  • Pulmonary Disease, Chronic Obstructive* / diagnosis
  • Pulmonary Disease, Chronic Obstructive* / epidemiology
  • Pulmonary Disease, Chronic Obstructive* / physiopathology
  • Pulmonary Disease, Chronic Obstructive* / psychology
  • Quality of Life*
  • Severity of Illness Index
  • Spirometry / methods
  • Statistics as Topic
  • Symptom Flare Up
  • United States / epidemiology