Subclinical atherosclerosis risk markers in patients with chronic obstructive pulmonary disease: A systematic review and meta analysis

Background and aims: Chronic obstructive pulmonary disease (COPD) is associated with increased cardiovascular morbidity and mortality. Identifying early changes of cardiovascular system before the occurrence of fatal clinical event is critical for the management of COPD. We performed a meta-analysis to investigate the associations between COPD and subclinical markers of cardiovascular risk. Methods: We searched PUBMED, EMBASE for studies published before Aug 1st, 2016, on the association between COPD and carotid intima-media thickness (CIMT), prevalence of carotid plaques, flow-mediated dilation (FMD), pulse-wave velocity (PWV) and augmentation index (Alx). Results: Thirty-two studies (3198 patients, 13867 controls) were included. Compared with controls, COPD patients had significantly higher CIMT (MD: 0.10 mm; 95% CI: 0.04, 0.16; p = 0.0007), PWV (SMD: 0.70; 95% CI: 0.52, 0.88; p < 0.0001), Aix (MD: 4.60%; 95% CI: 0.52, 8.68; p = 0.03), Aix@75 (Alx normalized to a heart rate of 75 beats per minute) (MD: 4.59%; 95% CI: 2.80, 6.38; p < 0.0001), prevalence of carotid plaque (OR: 2.54; 95% CI: 2.04, 3.15; p < 0.0001), and significantly lower FMD (MD: -4.21%; 95% CI: -6.71, -1.71; p = 0.001). Sensitivity and subgroups analyses substantially confirmed our results. Meta-regression analysis revealed that spirometry (as expressed by FEV1%predicted) might influence on PWV. Conclusions: These findings indicate that COPD, even in mild to moderate patients, had greater impaired markers of subclinical atherosclerosis and cardiovascular risk. However, further studies are still needed to address confounders, such as age, smoking, hypertension, diabetes etc, which might affect the associations in COPD patients. 2016 Elsevier Ltd. All rights reserved.