Abstract TMP106: Decline In The Severity Of Hospitalized Ischemic Stroke 2005-2015: The Greater Cincinnati/Northern Kentucky Stroke Study

Background: Monitoring changes in ischemic stroke severity at the population level is important as changes in risk factors and clinical treatments could influence stroke severity. We describe trends in the distribution of NIHSS across 3 time periods in a population-based epidemiologic stroke study. Methods: In 2005, 2010, and 2015 all adult acute ischemic strokes occurring within the Greater Cincinnati area presenting to 15 hospitals were ascertained using discharge codes (ICD-9 433-436; IDC-10 I63-I68, G45-46). Following physician verification, confirmed ischemic stroke cases underwent chart abstraction including estimation of a retrospective (rNIHSS) score at presentation. Descriptive statistics (rNIHSS median, IQR) were generated by survey year, demographics, and medical history. Using a binary definition of stroke severity (median rNIHSS score > 4 versus < 4), multivariable logistic regression was used to estimate changes in stroke severity over time, adjusting for potential confounders. Random effects were used to account for multiple admissions occurring in the same subject. Results: The number of ischemic stroke admissions in the 2005, 2010, and 2015 surveys was 1778, 1903, and 1933, respectively (Table). The median (IQR) rNIHSS scores were 3 (2-7), 3 (1-6), and 2 (1-6) across the 3 surveys, respectively; the proportion of admissions with rNIHSS > 4 was 48%, 39% and 37%, respectively. After adjusting for demographics, medical history and pre-stroke function, compared to 2005, the odds ratio for more severe stroke was 0.69 (95% CI= 0.60-0.79, p=0.001) in 2010 and 0.63 (95% CI= 0.55-0.73, p=0.001) in 2015. Conclusions: In this population- based study there was a statistically significant change in the severity of ischemic stroke hospitalizations with increases in the proportion of milder strokes over time. Potential reasons for this change need to be explored but could include changes in risk factors, clinical treatments or diagnostic approach.