Impact of Smoking on Functional Prognosis after Ischemic Stroke according to Deprivation: A Prospective Cohort Study

Background: Smoking influence on poststroke prognosis remains controversial. These conflicting results could be due to some residual confounding factors not fully considered in previous studies, including social deprivation. This study aimed to assess the joint impact of deprivation and smoking on functional outcomes after ischemic stroke. Methods: Between 2011 and 2014, 1,573 patients with a first-ever stroke were prospectively included in the French multicenter INDIA (“Inegalites sociales et pronostic des accidents vasculaires cerebraux à Dijon et Antilles-Guyane”) cohort study. Patients with ischemic stroke and available data on smoking, deprivation, and outcome were considered for the analysis (n = 1,242). Deprivation was assessed using the EPICES “Evaluation de la Précarité et des Inégalites de santé dans les Centres d’Examen de Santé” score. Primary outcome was functional outcome assessed with the modified Rankin Scale (mRS) score at 12 months. Association between smoking and moderate to severe disability (mRS score ≥3) was evaluated with logistic regression model. Interactions between smoking and deprivation were tested. Results: Smokers (n = 189, 15.2%) were younger and more often deprived (EPICES score ≥30.17) than nonsmokers. A significant interaction was found between smoking status and deprivation on disability (p = 0.003). In nondeprived patients, the odds of moderate to severe disability at 12 months were twice as high in smokers as in nonsmokers (adjusted OR = 2.08, 95% CI: 1.04–4.18). This association was not observed in deprived patients (adjusted OR = 0.89, 95% CI: 0.49–1.61). Conclusion: The effect of smoking on functional prognosis after ischemic stroke varied according to deprivation status, with poorer outcomes observed in nondeprived patients.