Statistics from Altmetric.com
We welcome the comments of van den Bemt et al regarding our review on obesity and chronic obstructive pulmonary disease (COPD). Their careful analysis of a large Dutch primary care population of COPD provides further evidence for an increased prevalence of obesity in patients with early-stage COPD. According to their data, about 17% of the patients in GOLD (Global Initiative for Chronic Obstructive Lung Disease) stage II are obese vs 11% in a healthy Dutch population.1 The prevalence of a body mass index (BMI) ⩾30 kg/m2 was significantly lower in GOLD III (14%) and substantially reduced in GOLD IV patients (2%). The results of van den Bemt et al furthermore show that obesity is clinically important in COPD patients, since it is related to increased dyspnoea. Although the association between BMI and breathlessness is not unique for patients with COPD,2 it indicates that the abundance of fat mass is a factor that should be taken into account in COPD management. Based on the existing prevalence data, the authors urge for research to be carried out into effective prevention and intervention strategies of obesity in COPD. Unfortunately van den Bemt et al were not able to distinguish in their study between the prevalence of fat abundance in absolute or relative terms (ie, obesity vs sarcopenic obesity). In our review, we specifically focused on the impact of excessive fat mass (in both absolute and relative terms) on the pathogenesis of systemic features of COPD such as systemic inflammation and cardiovascular disease rather than that of a high BMI per se, since pulmonary disease severity appears to be associated not only with a decline in BMI but also with a shift in body composition. Insight into the pathogenesis of a disturbed energy balance in COPD patients with fat abundance is needed to determine if a generic- or a disease- (and maybe even disease state-) specific intervention approach is needed. Fat mass is merely determined by an imbalance between dietary intake and energy expenditure. No data are yet available regarding dietary intake in obese and non-obese patients with COPD adjusting for GOLD stage. Several studies, however, have consistently demonstrated a very low physical activity level (the most variable component of energy expenditure) in patients with COPD.3 The studies so far therefore clearly point towards promoting exercise in early-stage COPD patients with obesity in order to improve energy balance, decrease dyspnoea and possibly also prevent adverse effects of fat abundance on cardiometabolic risk as outlined in our review.4
Competing interests: None.