Newly Diagnosed Leptospirosis and Subsequent Hemorrhagic Stroke

Background and Purpose: Preceding infection as an important risk factor for ischemic stroke has been reported but neglected for hemorrhagic stroke, especially in young and middle-aged patients. This study investigates whether newly diagnosed leptospirosis is associated with an increased risk of stroke. Methods: We identified 3699 in-patients who were aged ≥18 years and newly diagnosed with leptospirosis. We also randomly selected a comparison cohort 14 796 in-patients from the general population by using a propensity score matching method (at a 1:4 ratio). We analyzed the risks of stroke by using Cox proportional hazard regression models. Results: The adjusted hazard ratio (HR; 95% CI) of stroke for the leptospirosis group was 1.14 (0.93–1.38;P =0.200) as opposed to the comparison group after adjusting sex, age, and comorbidities. However, adjusted HR (95% CI) of ischemic stroke and hemorrhagic stroke was 1.01 (0.80–1.29) and 1.58 (1.12–2.23), respectively. The strength of association between leptospirosis and hemorrhagic stroke remained statistically significant after variation of leptospirosis and stroke definitions. The post hoc subgroup analysis indicated that a patient with leptospirosis had a significantly greater risk of hemorrhagic stroke in male (adjusted HR, 1.62 [95% CI, 1.08–2.44]) and individuals between age 18 and 39 (adjusted HR, 3.67 [95% CI, 1.33–10.14]). The risk of hemorrhagic stroke among people with leptospirosis was highest in the first 2 years after diagnosis (adjusted HR, 1.97 [95% CI, 1.15–3.38]).Conclusions: A 2.49-fold risk of stroke was found among the leptospirosis cohort of aged younger than 39 years. Age acted as an effect modifier between the leptospirosis and risk of new-onset stroke.