Abstract P601: Influenza-Like Illness as a Short-Term Risk Factor for Arterial Dissections

Abstract

Introduction: Arterial dissections often have no known identifiable risk factor. Whether infection/inflammation may play a role in the development of arterial dissection is uncertain. Hypothesis: Influenza-like illness (ILI) is associated with a heightened risk of arterial dissection. Methods: We performed a case-crossover analysis using administrative claims data on emergency department visits and acute care hospitalizations from 2006 to 2015 in NY and 2005-2015 in FL. We used previously validated International Classification of Diseases, Ninth Revision, Clinical Modification codes to identify patients with ILI and arterial dissection. Arterial dissection included the composite of cervical artery dissection (carotid and vertebral), coronary artery dissection, and aortic dissection. We compared the risk of arterial dissection in successive 30-day periods after ILI versus the corresponding 30-day periods one year earlier. We used McNemar test for matched data to calculate the absolute risk increases. Results: We identified 2,838,178 patients with ILI. The absolute increase in arterial dissection was 0.005% (95% CI, 0.004-0.006%) in the thirty days post ILI compared with the same period one year earlier (OR 3.3, 95% CI, 2.5-4.4). The absolute increase in arterial dissection attenuated over successive 30-day periods after ILI and was no longer significant after 120 days post ILI (Figure). Our results were similar in secondary analyses evaluating cervical, coronary, and aortic dissections separately. Conclusions: ILI is associated with a heightened short-term risk of arterial dissection. Further studies are warranted to evaluate mechanisms of how ILI and/or related inflammation leads to a heightened risk of systemic and cerebrovascular dissections.