Risk factors of acute cardiovascular events following acute exacerbation period for patients with COPD: a nested case-control study

Abstract

Background For patients with chronic obstructive pulmonary disease (COPD), the incidence of acute cardiovascular events (CVEs) increases during acute exacerbation (AE) period, causing increased inpatient mortality. Thus, we try to identify risk factors of acute CVEs in patients with AECOPD via a nested case-control study.Methods A total of 496 cases hospitalized for AECOPD were included into analysis, and followed-up for 6 months after discharge. Acute CVEs in the AE period were defined as the new or worsening acute coronary syndrome (ACS), arrhythmia, left ventricular disfunction (LVD). Risk factors were selected from several variables, including baseline characteristics and treatments in the stable period as well as symptoms, laboratory tests, complications and treatments in the AE period. Results Thirty cases (6.05%) had acute CVEs, including 2 with ACS, 13 with LVD, 19 with arrhythmia, and 4 deaths, with significantly increased mortality risk (P=0.001, OR=5.81). Moreover, patients who have had CVEs were inclined to have re-exacerbation within 3 months. Multivariate analysis showed that previous LVD history (P=0.004, OR=5.06), 20% increase in heart rate (HR) (P=0.003, OR= 10.19), electrolyte disturbance (P=0.01, OR= 4.24) and diuretics (P=0.002, OR = 6.37) were independent risk factors. In addition, usage of theophylline, fluoroquinolone and inhaled beta agonists in the AE period were not statistically associated with acute CVEs. Conclusions Our study preliminarily indicated that patients hospitalized for AECOPD with previous LVD history or increased HR need close observation and diuretics should be cautiously used with electrolyte monitoring. These findings needs to be confirmed in a large cohort.