Novel perspectives on trunk-to-peripheral fat ratio in hospitalized patients with chronic obstructive pulmonary disease.

Malnutrition plays a considerable role in the deterioration of chronic obstructive pulmonary disease (COPD). Nevertheless, current research indicates body mass index may not fully capture alterations in nutritional status. Trunk-to-peripheral fat ratio, measured by dual-energy x-ray absorptiometry (DXA) offers a more precise approach. This research aims to investigate the association between trunk-to-peripheral fat ratio and the severity of COPD as measured by COPD Assessment Test (CAT) scale, along with its related intermediary factors. We incorporated 168 patients admitted for COPD and obtained body composition data through DXA. The main outcome was 1-year CAT scale score, with 6-month CAT scale score serving as the secondary outcome. Significant disparities were observed between trunk-to-appendicular fat ratio (TAR) and trunk-to-leg fat ratio (TLR) across different groups with a 6-month CAT (all p < 0.05) and a 1-year CAT (all p < 0.05). After adjusting for covariates, TAR (OR = 0.330, p = 0.013) and TLR (OR = 0.525, p = 0.026) were independently correlated with one-year CAT. Upon inclusion of TAR in the initial model, the area under the curve (AUC) was 0.739 (95% CI 0.663-0.815, p < 0.001), along with an elevated Net Reclassification Improvement (NRI) of 37.81 (95% CI 7.85-67.77, p = 0.013) and Integrated Discrimination Improvement (IDI) of 3.39 (95% CI 0.63-6.14, p = 0.016). Similarly, the previous model's AUC and IDI climbed with the addition of TLR. Mediation analysis indicated that triglyceride levels partly influenced the correlation. Trunk-to-peripheral fat ratio was associated with the severity of COPD, which was partly mediated by triglycerides.