The impact of smoking on the severity of acute ischemic stroke

Objectives: This study investigated the impact of smoking on the initial severity of acute ischemic stroke and examined its subsequent outcome. Methods: Patient data was collected from the Stroke Registry in the Chang Gung Healthcare System (SRICHS). A total of 2650 patients admitted for acute ischemic stroke from January to December 2009 were included. Baseline characteristics were compared between smokers and non-smokers. Factors affecting the initial severity and the recovery from neurological deficit were examined by logistic regression analysis. The patients were further divided according to stroke mechanism for subgroup analysis. Results: The total number of smokers and non-smokers was 817 (31.9%) and 1833 (69.1%), respectively. Univariate analysis showed that smokers had lower NIHSS scores on admission than did non-smokers (P < 0.001). In subgroup analysis, smokers with small-vessel occlusions frequently had higher NIHSS scores on admission than did non-smokers (P = 0.001). However, smokers with cardioembolic stroke had lower NIHSS scores on admission as compared to non-smokers (P = 0.024). No subgroup had smoking as a significant factor for neurological recovery during hospitalization. Conclusions: Smoking correlated with higher NIHSS scores on admission for small-vessel occlusion. Conversely, it was associated with lower NIHSS scores on admission for cardioembolism.