Effects of Smoking on Short-Term and Long-Term Mortality after Aneurysmal Subarachnoid Hemorrhage

<b><i>Objective:</i></b> The relationship between smoking and clinical outcomes after aneurysmal subarachnoid hemorrhage (aSAH) is poorly clarified, and current pieces of evidence are inconsistent. The purpose of this multicenter cohort study is therefore to explore the relationship between smoking and mortality as well as several complications after aSAH. <b><i>Methods:</i></b> Databases of patient records were from 4 tertiary hospitals. We assessed the impact of tobacco use and tobacco dose (categorized based on smoking index [SI]) on several complication and overall outcome variables. The primary outcome was mortality within the longest follow-up. Logistic models were used to investigate univariate and multivariate relationships between predictors and outcomes. We also developed a propensity score matching for smoking status by using all known confounders. <b><i>Results:</i></b> A total of 6,578 patients with aSAH were analyzed. Current smoking and former smoking did not show association with mortality within the longest follow-up (odds ratio [OR], 0.95, 95% confidence interval [CI]: 0.69–1.30, <i>p</i> = 0.726; OR, 0.66, 95% CI: 0.38–1.15, <i>p</i> = 0.139, respectively). In addition, patients who were current smokers showed an independent association with the decreased occurrence of hydrocephalus (OR, 0.60; 95% CI: 0.41–0.88; <i>p</i> = 0.009) after matching all known confounders. We also found moderate smoking (SI between 384 and 625) was associated with reduced mortality in hospital. <b><i>Conclusions:</i></b> Our results indicated that in patients with aSAH, current smoking or former smoking was not associated with all-cause mortality up to 7-year follow-up.