In patients with chronic obstructive pulmonary disease (COPD), an assessment of physical performance, including 6-minute walk test (6MWT) and 4-minute gait speed (4MGS), may help to enhance cardiovascular (CV) risk evaluation. Results of the analysis were published in the journal BMJ Open.
The investigators sought to establish the predictive value of conventional CV disease risk factors in COPD, as well as to determine whether the addition of alternative CV measures and inflammatory markers can help to improve prediction beyond the use of conventional factors. The multicenter, observational Evaluation of the Role of Inflammation in Chronic Airways (ERICA) disease cohort study was conducted in the United Kingdom.
A total of 729 individuals with stable Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage II-IV COPD were enrolled in the ERICA study. This cohort study was designed to identify important CV and physical performance biomarkers that might be targeted to improve outcomes among patients with COPD. All of the participants had a clinical diagnosis of COPD, a history of smoking of ≥10 pack-years, postbronchodilator forced expiratory lung volume in 1 second (FEV1)/forced vital capacity ratio of <0.7 and FEV1 ≤80% of predicted normal lung function, were >40 years of age, and had been clinically stable for >4 weeks. The study was carried out in 5 UK centers.
Of the 729 patients enrolled in the study, 98% (714 of 729) of them could be linked with hospital admission and survival records, and were thus included in the current analysis. Baseline measurements obtained from the participants included aortic pulse wave velocity (aPWV), carotid intima–media thickness (CIMT), C-reactive protein (CRP), fibrinogen, body mass index (BMI), spirometry, BODE (Body mass index, airflow Obstruction, Dyspnea and Exercise capacity) Index, 4MGS, and 6MWT. The primary study outcome was defined as first reported occurrence (since study enrollment) of fatal or nonfatal hospitalized CV disease (ie, disease of the arteries, stroke, or heart failure). Secondary outcomes included all-cause and cause-specific mortality, which was defined as CV, pulmonary, cancer, or other.
Among the 714 study participants, 27% (192 of 714) experienced CV hospitalization and 6 individuals died of CV disease. The overall CV risk model C-statistic was 0.689 (95% CI, 0.688 to 0.691). CIMT and aPWV were not associated with the study outcome and did not improve CV disease model prediction. In contrast, BMI, CRP, GOLD stage, fibrinogen, BODE Index, 6MWT, and 4MGS were all associated with the study outcome independently of conventional risk factors (P <.05). Only 6MWT, however, improved the predictive discrimination of the CV risk model (C=0.727; 95% CI, 0.726 to 0.728).
A limitation of the study is that the majority of the study participants already had CVD and were on CV medications, which may be a confounding factor impacting the discriminative ability of CVD risk factors.
The investigators concluded that in individuals with COPD, poor physical performance demonstrated on the 6MWT improves the prediction of CV hospitalization.
Fermont JM, Fisk M, Bolton CE, et al; ERICA consortium. Cardiovascular risk prediction using physical performance measures in COPD: results from a multicentre observational study. BMJ Open. 2020;10(12):e038360. doi:10.1136/bmjopen-2020-038360