Introduction and Objectives Chronic Obstructive Pulmonary Disease (COPD) patients are at increased risk of cardiovascular disease. Previous studies have suggested that acute exacerbations of COPD (AECOPD) are associated with an increased risk of stroke in COPD patients. We aimed to characterise the size and duration of the increased risk of stroke following AECOPD as well as factors that modify the risk.

Methods Using data from the Clinical Practice Research Datalink linked with Hospital Episode Statistics, we conducted a self-controlled case series on COPD patients who had an AECOPD and a stroke. Fixed-effects conditional Poisson regression was utilised to estimate the incidence rate ratio (IRR) of stroke in the 91 day period following AECOPD compared with stable periods. The 91 day period was also segmented into shorter time periods, which were compared with stable periods in order to determine how the risk of stroke post-AECOPD changes over time. We stratified by various factors (including AECOPD severity, exacerbation frequency, cardiovascular disease history, and cardiovascular and respiratory drug prescription) to identify which modified this risk.

Results 3,466 COPD patients were identified as having at least one AECOPD and a first stroke during the study period. We observed an increased risk of stroke in the 91 day period following AECOPD compared with stable periods (IRR=1.47, 95% CI: 1.36–1.59), which peaked on days 4–7 (IRR=1.93, 95% CI: 1.57–2.37), not returning to baseline until after 91 days post-AECOPD. This increased risk was observed for ischaemic strokes only (IRR=1.51, 95% CI: 1.39–1.65). The relative risk of ischaemic stroke post-AECOPD was significantly higher for those with lower exacerbation frequency, and significantly lower for aspirin users and those with a previous angina diagnosis.

Conclusions There is a 1.47-fold increased risk of stroke in the 91 days following AECOPD which peaks on days 4–7 and does not return to baseline until after 91 days post-AECOPD. This may be used to inform physicians when their patients are at greatest risk of stroke following AECOPD and may provide the basis of future interventions such as the introduction of aspirin to reduce this risk and possibly reduce mortality in COPD patients.