Associations between BODE index and systemic inflammatory biomarkers in COPD

Abstract

Background: COPD is a multi-component disease and systemic inflammation represents one of the key mechanisms responsible for the systemic manifestations of this disorder, including skeletal muscle weakness and cachexia. Fat-free mass index (FFMI) which reflects better the skeletal muscle mass, has been shown to relate to both dyspnoea and exercise capacity. We hypothesized that the multidimensional BODE index, that reflects the multi-component nature of COPD, might be related to biomarkers of systemic inflammation. We further evaluated associations between FFMI and systemic inflammation.

Methods: BODE index and FFMI were calculated in 222 stable COPD patients and 132 smokers without from COPD. Systemic inflammation was evaluated with the measurement of leptin, adiponectin, CRP, IL-6, and TNF-α in serum samples of COPD patients.

Results: In patients with COPD, both BODE index and FFMI presented significant associations with leptin levels (R2 0.66 and 0.71, respectively), whereas FFMI presented an additional association with the levels of TNF-α (R2 0.37). No significant associations were observed in normal smokers.

Conclusions: Both BODE index and FFMI, are related to the circulating levels of leptin in patients with COPD, a fact that strengthens a possible role for leptin in the systemic inflammatory process of COPD. The additional association of FFMI with TNF-α further supports the closer association of FFMI with muscle wasting in COPD.