Most Read Articles
2 days ago
Exposure to corticosteroids in patients with autoimmune hepatitis (AIH) appears to contribute to increased risks of cataract, diabetes and bone fractures, a study has found. Notably, the fracture risk is elevated at low doses, while the risk of adverse events overall is dose-dependent and is reversible.
6 days ago
In patients with atrial fibrillation (AF) and stable coronary artery disease (CAD), rivaroxaban monotherapy is noninferior to combination treatment with an antiplatelet therapy in terms of cutting the risk of cardiovascular events and mortality, according to data from the AFIRE trial.
Elvira Manzano, 12 Nov 2019
Supplementation with omega-3 fatty acids or vitamin D3 for up to 5 years has no effect on kidney function in adults with type 2 diabetes (T2D), the VITAL-DKD* ancillary study has shown.
Jairia Dela Cruz, 5 days ago
Many patients with nonvalvular atrial fibrillation (NVAF) in Thailand use anticoagulants, but the uptake of nonvitamin-K oral anticoagulants remains suboptimal despite showing an upward trend, according to data from the COOL-AF registry presented at the European Society of Cardioloy (ESC) Asia Congress 2019 with APSC and AFC.

6 times higher risk of heart attack in the week after flu diagnosis

Pearl Toh
05 Feb 2018

The risk of having an acute myocardial infarction (AMI) is sixfold higher within the week after laboratory-confirmed influenza infection, reveals a study.

“Our findings are important because an association between influenza and AMI reinforces the importance of vaccination,” said lead author Dr Jeffrey Kwong of the Institute of Clinical Evaluative Science in Toronto, Canada.

The self-controlled case-series study involved 332 patients (median age 77 years) hospitalized for AMI within the 1-year period before or after a positive laboratory test result for influenza. Hospitalization episodes were categorized into those occurring within the “risk interval” if they fell within the first 7 days after respiratory specimen collection, or within the “control interval” if they occurred within the 1 year before or after the risk interval. [N Engl J Med 2018;378:345-353]

A higher rate of AMI hospitalization occurred during the 7 days after laboratory-confirmed influenza infection compared with during the control interval (20 vs 3.3 admissions/week).

This corresponds to a six times greater incidence ratio of AMI hospitalization during the risk interval than the control interval (6.05, 95 percent confidence interval [CI], 3.86–9.50). The risk of AMI was particularly high in the period immediately after influenza diagnosis, with an incidence ratio of 6.30 (95 percent CI, 3.25–12.22) for days 1 through 3 and 5.78 (95 percent CI, 3.17–10.53) for days 4 through 7.

There was no increase in AMI incidence after day 7 of influenza detection (incidence ratios, 0.60 and 0.75 for days 8–14 and days 15–28, respectively).

“The risk of acute MI is greatest in the week after the detection of influenza … After that first week, [the risk] does seem to go back down to baseline,” observed Kwong.

Subgroup analyses showed that AMI incidence increased after influenza infection among adults aged >65 years vs ≤65 years (incidence ratios, 7.31 vs 2.38; p-interaction=0.14) and among those with first hospitalization for AMI vs with prior AMI history (6.93 vs 3.53; p-interaction=0.29), although no significant differences were observed between subgroups.

Also, AMI incidence was higher within 7 days of detection of influenza B compared with influenza A (incidence ratios, 10.11 vs 5.17; p-interaction=0.19), but the difference was not significant. Alternative exposures to respiratory syncytial virus (incidence ratio, 3.51) and other respiratory viruses (incidence ratio, 2.77) were also associated with a higher AMI incidence although the incidence ratios were lower than for influenza infection.

“Our findings, combined with previous evidence that influenza vaccination reduces cardiovascular events and mortality, support international guidelines that advocate for influenza immunization in those at high risk of a heart attack … [such as] persons older than 65 years,” said Kwong. “People at risk of heart disease should take precautions to prevent respiratory infections, and especially influenza, through measures including vaccinations and handwashing.”

Other strategies to minimize the risk of cardiovascular events associated with respiratory infections include promoting infection prevention practices such as respiratory etiquette and social distancing, added Kwong and co-authors.

“In the context of chronic atherosclerotic vascular disease, an infectious illness may cause an acute coronary syndrome through acute inflammation, biomechanical stress, and vasoconstriction,” proposed the researchers on the possible mechanisms underlying the association.

Meanwhile, as the results are based on laboratory-confirmed respiratory infections (indicative of sufficient severity to call for a laboratory testing), the researchers cautioned against generalizing the findings to milder infections which usually do not require testing for respiratory viruses.      

 

 

Digital Edition
Asia's trusted medical magazine for healthcare professionals. Get your MIMS Doctor - Malaysia digital copy today!
Sign In To Download
Editor's Recommendations
Most Read Articles
2 days ago
Exposure to corticosteroids in patients with autoimmune hepatitis (AIH) appears to contribute to increased risks of cataract, diabetes and bone fractures, a study has found. Notably, the fracture risk is elevated at low doses, while the risk of adverse events overall is dose-dependent and is reversible.
6 days ago
In patients with atrial fibrillation (AF) and stable coronary artery disease (CAD), rivaroxaban monotherapy is noninferior to combination treatment with an antiplatelet therapy in terms of cutting the risk of cardiovascular events and mortality, according to data from the AFIRE trial.
Elvira Manzano, 12 Nov 2019
Supplementation with omega-3 fatty acids or vitamin D3 for up to 5 years has no effect on kidney function in adults with type 2 diabetes (T2D), the VITAL-DKD* ancillary study has shown.
Jairia Dela Cruz, 5 days ago
Many patients with nonvalvular atrial fibrillation (NVAF) in Thailand use anticoagulants, but the uptake of nonvitamin-K oral anticoagulants remains suboptimal despite showing an upward trend, according to data from the COOL-AF registry presented at the European Society of Cardioloy (ESC) Asia Congress 2019 with APSC and AFC.