Obesity and COPD: associated symptoms, health-related quality of life, and medication use

Abstract

Background: There is little data about the combined effects of COPD and obesity. We compared dyspnea, health-related quality of life (HRQoL), exacerbations, and inhaled medication use among patients who are overweight and obese to those of normal weight with COPD.

Methods: We performed secondary data analysis on 364 Veterans with COPD. We categorized subjects by body mass index (BMI). We assessed dyspnea using the Medical Research Council (MRC) dyspnea scale and HRQoL using the St. George's Respiratory Questionnaire. We identified treatment for an exacerbation and inhaled medication use in the past year. We used multiple logistic and linear regression models as appropriate, with adjustment for age, COPD severity, smoking status, and co-morbidities.

Results: The majority of our population was male (n = 355, 98%) and either overweight (n = 115, 32%) or obese (n = 138, 38%). Obese and overweight subjects had better lung function (obese: mean FEV(1) 55.4% ±19.9% predicted, overweight: mean FEV(1) 50.0% ±20.4% predicted) than normal weight subjects (mean FEV(1) 44.2% ±19.4% predicted), yet obese subjects reported increased dyspnea [adjusted OR of MRC score ≥2 = 4.91 (95% CI 1.80, 13.39], poorer HRQoL, and were prescribed more inhaled medications than normal weight subjects. There was no difference in any outcome between overweight and normal weight patients.

Conclusions: Despite having less severe lung disease, obese patients reported increased dyspnea and poorer HRQoL than normal weight patients. The greater number of inhaled medications prescribed for obese patients may represent overuse. Obese patients with COPD likely need alternative strategies for symptom control in addition to those currently recommended.

Figure 1. For every given severity of airflow obstruction, obese patients are more dyspneic than normal weight patients

We calculated the adjusted predicted MRC score from the multivariable linear model containing BMI category, FEV1 % predicted, age, smoking, diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease and congestive heart failure and plotted it for each subject by BMI category. Regression lines for each BMI category also shown. (Normal weight: , ; Overweight: , ; Obese: , )

Figure 2. Obese patients report worse health-related quality of life than normal weight patients

We calculated the adjusted predicted SGRQ score from the multivariable linear model containing BMI, FEV1 % predicted, age, smoking, diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease and congestive heart failure and plotted it for each subject by BMI category. Regression lines for each BMI category shown. (Normal weight: , ; Overweight: , ; Obese: , )

Figure 3. Obese patients are prescribed more long-acting inhaled medications than normal weight patients

We calculated the adjusted probability of long-acting beta-agonist (LABA) and inhaled corticosteroid (ICS) prescription from the multivariable logistic model containing BMI, FEV1 % predicted, age, smoking, diabetes mellitus, hypertension, hyperlipidemia, coronary artery disease and congestive heart failure and plotted it for each subject by BMI category. The adjusted number of medication classes was similarly calculated from the multivariable linear regression model. Regression lines for each BMI category also shown. (Normal weight: , ; Overweight: , ; Obese: , )