The association between the BRI and all-cause and cardiovascular mortality in COPD patients

Waist circumference (WC) has been linked to exacerbations in chronic obstructive pulmonary disease (COPD), but the relationship between WC, height, and the Body Roundness Index (BRI) with mortality in COPD patients remains unclear. This study investigates the association between BRI and both all-cause and cardiovascular mortality in COPD patients. Data from 3,672 COPD participants (1,517 men and 2,155 women; mean age: 53.17 ± 16.46 years) were obtained from NHANES (1999-2018). Multivariable Cox proportional hazards models, Kaplan-Meier analysis, Nelson-Aalen cumulative hazard plots, and restricted cubic spline analyses were used to assess the relationship between BRI and mortality. ROC curves were constructed to evaluate BRI's predictive performance. Subgroup and sensitivity analyses ensured robustness of the models. The BRI was associated with all-cause (HR: 1.12, 95% CI: 1.05-1.19) and cardiovascular mortality (HR: 1.14, 95% CI: 1.01-1.29). Kaplan-Meier curves and Nelson-Aalen plots demonstrated that higher BRI quartiles correlated with lower survival probabilities and increased cumulative mortality incidence. ROC curve analysis showed that BRI outperformed other models in predicting all-cause AUC: 0.81 (0.79-0.82) and cardiovascular mortality AUC: 0.79 (0.76-0.81). A significant interaction was observed between BRI and alcohol consumption for all-cause mortality. Results remained consistent after excluding participants who died within two years (HR: 1.10, 95% CI: 1.03-1.18) and in the alcohol-consuming subgroup (HR: 1.14, 95% CI: 1.05-1.24). The BRI is associated with increased all-cause and cardiovascular mortality in COPD patients, with higher BRI quartiles linked to greater mortality risk. Targeting BRI may offer a potential strategy to reduce mortality in this population.