Respiratory infections can act as triggers for acute myocardial infarction (MI) and stroke, according to the results of a study published in the European Respiratory Journal.
Charlotte Warren-Gash, MRCP, FFPH, PhD, of the Faculty of Epidemiology & Population Health, London School of Hygiene & Tropical Medicine in London, United Kingdom, and colleagues used national infection surveillance data linked with the Scottish Morbidity Record to identify adults with a first MI or stroke from January 1, 2004, to December 31, 2014, who also had a record of laboratory-confirmed respiratory infection during that period. They generated age- and season-adjusted incidence ratios (IR) for MI (n=1227) or stroke (n=762) after infections compared with baseline time using a self-controlled case series analysis.
The authors found substantially increased MI rates during the week after Streptococcus pneumoniae and influenza infections. The adjusted IRs for days 1 to 3 were 5.98 and 9.80 for those infections, respectively. As for stroke, the rates after infection were similarly elevated and remained so for 28 days after the infection. On days 1 to 3, the adjusted IRs were 12.3 and 7.82 for S pneumoniae and influenza infections, respectively. With respect to other respiratory viruses, although there was an association with increased MI and stroke, only the day 4 to 7 estimate for stroke was statistically significant.
The study was limited by the relatively small population size in Scotland that prohibited some subgroup analyses. For example, it was not possible to determine the effects of individual noninfluenza respiratory viruses on vascular events or to examine the effects of age in detail. The investigators also noted that they were unable to investigate the effects of coinfections separately because of the small number of patients involved.
The authors argued that their findings regarding the specific triggering effects of influenza and S pneumoniae on MI and stroke emphasize the importance of increasing influenza and pneumococcal vaccination in this population, particularly in those with existing heart disease. These findings also strengthen the case for considering antithrombotic strategies during acute respiratory infections for vulnerable patients.
Warren-Gash C, Blackburn R, Whitaker H, McMenamin J, Hayward AC. Laboratory-confirmed respiratory infections as triggers for acute myocardial infarction and stroke: a self-controlled case series analysis of national linked datasets from Scotland. Eur Respir J. 2018;51(3):1701794.