Cardiovascular Risks Associated with Patients Infected with Scrub Typhus: A Nationwide Cohort Study

BackgroundScrub typhus is an infectious disease that affects multiple organs. However, the long-term cardiovascular (CV) risk in survivors remains unknown. MethodA retrospective cohort study used administrative claims data from the National Health Insurance Research Database (NHIRD) to investigate the CV risk of scrub typhus survivors from January 1, 2010, to December 31, 2015. People who had prior CV events before the diagnosis of scrub typhus were excluded. The CV outcomes of interest were acute myocardial infarction (AMI), heart failure hospitalization (HFH), hemorrhagic or ischemic stroke, new-onset atrial fibrillation (AF), aneurysm or dissection of aorta, venous thromboembolism (VTE), and CV death. ResultA total of 2,269 patients with scrub typhus and without a prior CV event were identified (mean age 47.8{+/-}16.1 years, 38.0% female). The health control cohort (n=2,264) was selected to compare by the frequency matching with age, gender, and co-morbidities with patients with scrub typhus. The incidence of HFH, new-onset AF, and total events was significantly higher among patients with scrub typhus than the control cohort with an adjusted hazard ratio (aHR) of 1.97, 95% confidence interval (CI) 1.13-3.42 for HFH; 2.48, 95% CI: 1.23-5.0 for new-onset AF; 1.43, 95% CI: 1.08-1.91 for total CV events, respectively. The event rates of other outcomes were similar between the two groups. ConclusionIn the cohort study, survivors of scrub typhus are at heightened risk of subsequent CV events, especially for HFH and new-onset AF. These findings serve as an important reminder to physicians regarding the significant CV risk that remains present following acute scrub typhus infection.