The BODE Index prognostic score is an independent determinant of arterial stiffness in Chronic Obstructive Pulmonary Disease (COPD)

Abstract

Introduction: COPD is associated with increased cardiovascular risk, independent of established risk factors. Arterial stiffness is a surrogate of cardiovascular risk and we sought to determine its relationship with COPD severity and prognosis in the ERICA (Evaluation of role of inflammation in airways disease) multi-site UK study: the largest cohort study focusing on cardiovascular manifestations in COPD. Methods: Spirometry and haemodynamic measures (aortic pulse wave velocity (aPWV), augmentation index (AIx)) were performed in 729 COPD subjects aged ≥40 years. COPD severity was classified by BODE Index [BMI (low BMI worse prognosis), Obstruction (FEV1), Dyspnoea (mMRC score), Exercise tolerance (6-minute walk distance) high BODE index: worse outcome], a validated score based on clinical variables and an independent predictor of mortality in COPD. Results: Mean aPWV was 10.3 (SD 2.6) m/s, AIx 27 (10)%. BODE correlated with aPWV (R = 0.2, p = 0.0001) and this was maintained when adjusted for study site, age, supine HR and MAP, years smoked and cardiovascular comorbidities (MI, stroke, diabetes, peripheral vascular disease), (β = 0.2, p = 0.0001). BODE was also a determinant of AIx when adjusted for site, age, seated HR and MAP, years smoked and cardiovascular comorbidities (β = 0.1, p = 0.02). Conclusions: BODE is associated with arterial stiffness in COPD, independent of traditional risk factors. Its composite variables are not on the causal pathway for vascular stiffness, so its association likely reflects patient susceptibility to smoke injury in the lungs and vasculature. BODE may also enhance cardiovascular risk stratification in COPD, since its relationship with stiffness was independent of self-reported cardiovascular comorbidities.