Obesity in COPD: Revealed and Unrevealed Issues

Abstract

The interactions between obesity and chronic obstructive pulmonary disease (COPD) are being increasingly explored. In part, this is due to the globally increasing prevalence rates of obesity. The prevalence of obesity in COPD patients is variable, and it seems that obesity is more common in COPD patients compared with subjects who do not have COPD. However, further studies are encouraged in this area due to observed inconsistencies in the current data. In this review, we focus on the knowledge of the effects of obesity on dyspnea, pulmonary function, exercise capacity and exacerbation risk. Reduction of dyspnea is one of the main therapy targets in COPD care. There is still no consensus as to whether obesity has a negative or even a positive effect on dyspnea in COPD patients. It is hypothesized that obese COPD patients might benefit from favourable respiratory mechanics (less lung hyperinflation). However, despite less hyperinflation, obesity seems to have a negative influence on exercise capacity measured with weight-bearing tests. This negative influence is not seen with weight-supported exercise such as cycling. With respect to severe exacerbations, obesity seems to be associated with better survival. In summary, it is concluded that due to differences in study methodology and cohort selection, there are still too many knowledge gaps to develop guidelines for clinical practice. Further exploration is needed to get conclusive answers.

Pattern of comorbidities and 1-year mortality in elderly patients with COPD hospitalized in internal medicine wards: data from the RePoSI Registry

“…Only the final model is shown according to Hosmer-Lemeshow methodology. For the selection of variables see appendix and statistical analysis section consistently with recent data that seem to confirm that obesity is more common in COPD patients compared to subjects who do not have COPD [20]. Interestingly, individuals with a diagnosis of COPD had more frequent mood changes, indicating higher level of distress, in agreement with those from the NHANES study of 20.6% of subjects with COPD suffering from depression [21].…”

“…Our analysis showed that COPD in-patients are more often older men, smokers or former smokers, and live with their relatives, in agreement with our previous findings [ 19 ]. Moreover, COPD patients are severe obese consistently with recent data that seem to confirm that obesity is more common in COPD patients compared to subjects who do not have COPD [ 20 ]. Interestingly, individuals with a diagnosis of COPD had more frequent mood changes, indicating higher level of distress, in agreement with those from the NHANES study of 20.6% of subjects with COPD suffering from depression [ 21 ].…”

Effects of intraoperative individualized PEEP on postoperative atelectasis in obese patients: study protocol for a prospective randomized controlled trial

“…For patients undergoing general anesthesia with mechanical ventilation, about 75% of patients develop a state of local alveolar non-ventilation during surgery. Local atelectasis leads to ventilation/blood flow imbalance and intrapulmonary shunt and even induce hypoxemia, which is more pronounced in obese patients [20][21][22][23]. Compared with zero end-expiratory pressure (ZEEP), PEEP can improve end-expiratory long volume (EELV), increase oxygenation, and improve respiratory system compliance (C RS ), dependent lung ventilation, and post-operative lung function [24].…”

Obesity and the Lung: What We Know Today

“…Obesity can also cause hypoxemia in the lung via hypoventilation, associated comorbidities, reduction of FRC, shunt, and ventilation/perfusion imbalance. The association between hypoxemia and obesity as well as measurements of the lung’s diffusing capacity for carbon monoxide (DLCO) in obese patients is reported controversially in different studies [6, 10, 44, 45].…”

“…It is both possible that COPD is a risk factor for obesity or vice versa. While some studies suggest that obesity leads to more dyspnea in COPD, other studies found no effect [45].…”