Risk of Myocardial Infarction (MI) Associated with Acute Exacerbations of COPD (AECOPD)

Risk of myocardial infarction (MI) associated with acute exacerbations of COPD (AECOPD): effect modification bycardiovascular drugs

Authors Kieran J Rothnie1,2, Hana Müllerová3, Liam Smeeth2, Neil Pearce2, Ian Douglas2, Jennifer K Quint1,2

Author affiliations

1. Respiratory Epidemiology, Public Health and Occupational Medicine, National Heart and Lung Institute, Imperial College London

2. Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine

3. Respiratory Epidemiology, GlaxoSmithKline R&D, Uxbridge

Background
Chronic obstructive pulmonary disease is a common progressive disease characterised by airflow limitation which is not reversible. Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are worsening of symptoms of cough, dyspnoea and sputum production and are often triggered by infections. Previous studies have suggested that AECOPD may represent periods of increased risk of myocardial infarction (MI) for those with COPD.

Objectives

We aimed to use a within person design to investigate whether use of beta-blockers modifies the relationship between AECOPD and risk of MI.
Methods
We identified COPD patients with both an AECOPD and a first MI between 01/01/04-31/03/14 from the UK Clinical Practice Research Datalink (CPRD) and Hospital Episodes Statistics using previously validated algorithms. We performed a self-controlled case series to make within person comparisons of the rate of MI in the 91 days following onset of an AECOPD compared to their own stable periods for both frequent(≥2 per year) and infrequent exacerbators (<2 per year) measured in the year before entry to the study.Analyses were adjusted for the effects of season and we controlled for age in 5 year age bands. We then investigated effect modification by beta-blockers, defined as at least one prescription in the year before entry to the study.

Results
We included 3,886 COPD patients with a first MI. Risk of MI was elevated in the 91 days following an AECOPD compared to stable periods for both frequent (IRR 1.19, 95% CI 1.08-1.31), and infrequent exacerbators (IRR 1.49, 95% CI 1.30-1.71). The effect of AECOPD on MI was modified by use of beta-blockers for both frequent (users IRR 1.08, 0.92-1.27; non-users IRR 1.27, 1.12-1.44; p for interaction 0.006) and infrequent exacerbators (users IRR 1.44, 1.18-1.76; non-users IRR 1.55, 1.27-1.89;p for interaction 0.001).

Conclusions
AECOPD represent a period of increased risk of MI for those with COPD. The effect of AECOPD on risk of MI is lowerin beta-blocker users.