The influence of initial stroke severity on the likelihood of unfavourable clinical outcome and death at 90 days following acute ischemic stroke: a tertiary hospital stroke register study

Background and Purpose: Epidemiological studies on the extent of the interaction and/or influence of stroke severity on clinical outcomes are important. The aim of the present study was to investigate the putative (and degree of) impact of initial stroke severity in predicting the overall functional outcome, in-hospital placement, and mortality in acute ischemic stroke (AIS) in comparison with age, admission to the stroke unit and thrombolytic treatment. Materials and Methods: The John Hunter Hospital acute stroke register was used to collect a retrospective cohort of AIS patients being assessed for reperfusion therapy and admitted between January 2006 and December 2013. Univariate and multivariate logistic regression and receiver operating characteristics analyses were used to assess associations with functional outcome, in-hospital placement, and mortality at 90 days. Results: 608 AIS patients with complete datasets were included in the study. On univariate analysis, initial stroke severity showed the strongest independent association to the risk of death within 90 days (Odds ratio (OR) =1.15; P < 0.001; 95% confidence interval (CI) = [1.11, 1.18]); age was a less significant independent influence (OR = 1.02; P = 0.049; 95% CI = [1.00, 1.03]). Multivariate logistic regression analysis demonstrated that initial stroke severity independently predicted the 90 day mortality (OR = 1.16; 95% CI = [1.12, 1.2]; P < 0.0001) and unfavorable outcome (OR = 1.16; 95% CI = [1.13, 1.2]; P < 0.0001). Higher National Institute of Health Stroke Scale at admission was significantly associated with longer in-hospital placement (P < 0.0001). Conclusions: In this acute stroke cohort, initial stroke severity had a major impact on the likelihood of death following an AIS and appears to be the dominant influence on the overall stroke outcome and in-hospital placement.