Increased Risk of Acute Myocardial Infarction and Stroke During Hemorrhagic Fever With Renal SyndromeCLINICAL PERSPECTIVE: A Self-Controlled Case Series Study

Background— We recently observed that cardiovascular causes of death are common in patients with hemorrhagic fever with renal syndrome (HFRS), which is caused by hantaviruses. However, it is not known whether HFRS is a risk factor for the acute cardiovascular events of acute myocardial infarction (AMI) and stroke. Methods and Results— Personal identification numbers from the Swedish HFRS patient database (1997–2012; n=6643) were cross-linked with the National Patient Register from 1987 to 2011. Using the self-controlled case series method, we calculated the incidence rate ratio of AMI/stroke in the 21 days after HFRS against 2 different control periods either excluding (analysis 1) or including (analysis 2) fatal AMI/stroke events. The incidence rate ratios for analyses 1 and 2 for all AMI events were 5.53 (95% confidence interval [CI], 2.6–11.8) and 6.02 (95% CI, 2.95–12.3) and for first AMI events were 3.53 (95% CI, 1.25–9.96) and 4.64 (95% CI, 1.83–11.77). The incidence rate ratios for analyses 1 and 2 for all stroke events were 12.93 (95% CI, 5.62–29.74) and 15.16 (95% CI, 7.21–31.87) and for first stroke events were 14.54 (95% CI, 5.87–36.04) and 17.09 (95% CI, 7.49–38.96). The majority of stroke events occurred in the first week after HFRS. Seasonal effects were not observed, and apart from 1 study, neither sex nor age interacted with the associations observed in this study. Conclusions— There is a significantly increased risk for AMI and stroke in the immediate time period after HFRS. Therefore, HFRS patients should be carefully monitored during the acute phase of disease to ensure early recognition of symptoms of impending AMI or stroke.