Sudden hearing loss and the risk of subsequent cerebral ischemic stroke

Sudden hearing loss and the risk of subsequent cerebral ischemic stroke. Objective: Very few studies have investigated the risk of ischemic stroke after an episode of sudden sensorineural hearing loss (SSNHL), and findings have been controversial. The aim of this study was to estimate the risk of ischemic stroke among SSNHL patients within the province of Ferrara and compare the findings with data available in the literature. Methods: This was a cohort study using hospital discharge records. The observation period was from 1 January 2001 to 31 December 2012. The study cohort consists of all adult patients hospitalized with a principal diagnosis of SSNHL (n=484) and all adult patients with a diagnosis of ischemic stroke (n=9985) among the resident population of the province of Ferrara, Emilia-Romagna, Italy. We calculated the incidence of SSNHL and ischemic stroke, as well as the incidence of ischemic stroke within the group of patients who experienced SSNHL. Results: During the period 2001-2012 in Ferrara, the average annual crude incidence of SSNHL was 11.4/100,000 (95% CI 10.4-12.4), while the average annual crude incidence of the first ischemic stroke was 235.3/100,000. During the mean observation time period of 6 years, the expected and observed cases of ischemic stroke among the 484 patients with SSNHL did not differ significantly (6.8 expected vs. 9 observed [95% Poisson Confidence Interval 4.11-17.08]). Conclusions: Our findings suggest that SSNHL does not significantly increase the risk of ischemic stroke.