Predictors of acute cardiovascular events following acute exacerbation period for patients with COPD: a nested case–control study

BACKGROUND: It has been noted that there is an increase in the incidence of acute cardiovascular events (CVEs) in patients with chronic obstructive pulmonary disease (COPD) during an acute exacerbation (AE), thereby causing increased inpatient mortality. Thus, we have tried to identify predictors of acute CVEs in patients with AECOPD via a nested case–control study. METHODS: A total of 496 cases hospitalized for AECOPD were included in this study, and followed-up for up to 6 months after discharge. Acute CVEs in the AE period were defined as a new or worsening acute coronary syndrome (ACS), arrhythmia, or left ventricular disfunction (LVD). Predictors of CVEs 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, namely 2 had ACS, 13 had LVD and 19 experienced some form of arrhythmia. Four deaths were observed in the CVE group, with significantly increased death risk compared with the non-CVE group (P = 0.001, OR = 5.81). Moreover, patients who had CVEs were more prone 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 predictors of CVEs. In addition, usage of theophylline, fluoroquinolone and inhaled beta agonists in the AE period were not statistically associated with acute CVEs. CONCLUSIONS: Our preliminary study indicates that patients hospitalized for AECOPD with previous LVD history or increased HR need close observation and diuretics should be cautiously used with regular electrolyte monitoring. These findings need to be confirmed in a large cohort.