Is smoking associated with favourable outcome in tPA-treated stroke patients?

Smoking has been associated with improved outcome in thrombolysed patients with myocardial infarction and higher recanalization rates in stroke patients treated with tissue plasminogen activator (tPA). We hypothesized a positive association between smoking and favourable outcome in stroke patients treated with tPA and no such association in acute stroke patients not treated with tPA, suggesting a beneficial effect of smoking on thrombolysis with tPA.

Stroke patients treated with tPA and stroke patients not treated with tPA, but presenting within 6 h after stroke onset, were included in two separate groups. Three groups were defined according to smoking habits: current smoking, previous smoking and no smoking. Functional outcome by modified Rankin Scale (mRS) was assessed after 1 week or at discharge, if discharged earlier. Favourable outcome was defined as mRS 0 or 1.

A total of 399 patients were treated with tPA (94 current smokers, 148 previous smokers and 157 non-smokers), whereas 424 patients were not treated with tPA (90 current smokers, 164 previous smokers and 170 non-smokers). Current smoking was independently associated with favourable outcome in patients treated with tPA when adjusted for confounders (OR 2.08, 95% CI 1.09-3.95, P = 0.025). There was no such association in acute stroke patients not treated with tPA (OR 1.26, 95% CI 0.67-2.36, P = 0.472).

Our study showed an association between current smoking and favourable short-term outcome in stroke patients treated with tPA, but not in acute stroke patients not treated with tPA. This may indicate a more effective thrombolysis with tPA in smokers.