Beyond the infection: mapping the risk of cardiovascular events post-scrub typhus in a nationwide cohort study

Abstract

ABSTRACTScrub typhus, caused by Orientia tsutsugamushi, often involves multiple organs, but its cardiovascular (CV) sequelae in survivors remain under-researched. This retrospective cohort study analyzed data from the National Health Insurance Research Database (NHIRD) spanning 2010-2015 to assess CV risks among scrub typhus survivors. Excluding those with prior CV events, we focused on outcomes such as acute myocardial infarction (AMI), heart failure hospitalization (HFH), strokes, new-onset atrial fibrillation (AF), aortic aneurysm or dissection, venous thromboembolism (VTE), and CV death. From 2,269 scrub typhus patients without previous CV events (mean age 47.8 ± 16.1; 38.0% female), and a matched control group (n = 2,264), we observed a higher incidence of HFH, new-onset AF, and total CV events in the scrub typhus cohort. Adjusted hazard ratios (aHRs) were 1.97 (95% CI: 1.13-3.42) for HFH, 2.48 (95% CI: 1.23-5.0) for new-onset AF, and 1.43 (95% CI: 1.08-1.91) for total CV events. Other outcomes did not significantly differ. Scrub typhus survivors exhibit an increased risk of CV events, particularly HFH and new-onset AF, underscoring the importance of heightened physician awareness and post-infection cardiac surveillance.

Keywords: Orientia tsutsugamushi; Scrub typhus; atrial fibrillation; cardiovascular risk; heart failure hospitalization.

Figure 1.

Flow chart of selection and inclusion of patients with scrub typhus and the control population.

Figure 2.

Cardiovascular outcomes in people with or without scrub typhus infection. Shown are the cumulative incidence of cardiovascular events in patients with scrub typhus infection, as compared with control individuals, on the outcome of acute myocardial infarction (Panel A); the outcome of heart failure hospitalization (Panel B); the outcome of hemorrhagic stroke (Panel C); the outcome of ischemic stroke (Panel D). P values were estimated with the use of Cox regression models.

Figure 3.

Cardiovascular outcomes in people with or without scrub typhus infection. Shown are the cumulative incidence of cardiovascular events in patients with scrub typhus infection, as compared with control individuals, on the outcome of new-onset atrial fibrillation (Panel A); the outcome of aneurysm and dissection of aorta (Panel B); the outcome of venous thromboembolism (Panel C); the outcome of cardiovascular death (Panel D); the outcome of all-cause death (Panel E); and the outcome of all major cardiovascular events (Panel F). All relevant adverse cardiovascular events composite of acute myocardial infarction, heart failure hospitalization, ischemic stroke, hemorrhagic stroke, new-onset atrial fibrillation, aortic disease, venous thromboembolism, or cardiovascular death. P values were estimated with the use of Cox regression models.

Figure 4.

Summary of adjusted Cox proportional hazard analysis for cardiovascular events in the study.