Reinvestigation of the risk of stroke after dengue virus infection: A population-based cohort study

Background: Dengue virus (DENV) infection is the most prevalent mosquito-borne viral disease. Stroke is a severe manifestation of dengue. However, few large-scale studies have investigated post-dengue risk of stroke. Methods: This population-based cohort study included 57,934 newly diagnosed, laboratory-confirmed dengue patients in Taiwan from 2002 to 2015; patients were matched to nondengue individuals by age, sex, and area of residence at a ratio of 1:4 (n = 231,736). We used subdistribution hazard regression to evaluate short-term (≤ 30 days), medium-term (31–365 days), and long-term (1–3 years) risk of stroke after DENV infection. The robustness of the results to unmeasured confounding was assessed with E-values. Results: DENV infection was associated with a significantly increased risk of overall stroke (aSHR 4.51; 95% CI: 3.23–6.32; P < 0.0001; E-value = 8.49), hemorrhagic stroke (aSHR 4.13; 95% CI: 2.20–7.76; P < 0.0001; E-value =7.73), and ischemic stroke (aSHR 3.80; 95% CI: 2.37–6.11; P < 0.0001; E-value = 7.06) within 30 days. Stratified analysis by age showed that the aSHRs for overall stroke, hemorrhagic stroke, and ischemic stroke were larger among dengue patients aged ≥ 65 during the first 30 days. The 30-day risks of overall stroke, hemorrhagic stroke, and ischemic stroke among elderly dengue patients were 6.71, 1.29, and 3.49 per 1000, respectively. No increased risk was observed after 30 days. Conclusion: DENV infection was associated with a significant short-term increased risk of stroke. Clinical practitioners should remain alert to patients with stroke-associated symptoms during epidemic seasons, especially elderly patients.