New research has shown how smoking after an ischaemic stroke leads to an increased risk for major cardiovascular (CV) events and death.
Despite the effects smoking has leading up to the time of stroke being well known, there has been little research into the risks persistent smoking after an ischaemic stroke has.
In order to conduct this analysis, researchers from the Medical University of South Carolina used data from the Small Subcortical Strokes trial, a randomised multicentre trial, conducted at 82 centres in the Americas and Spain, between 2003 and 2012.
In this research, smoking status from month 3 after ischaemic stroke was related with CV outcomes and death through an average follow-up of 38.8-42.7 months.
Major adverse CV events (MACE) were defined as all-cause death, ischaemic or haemorrhagic stroke, and myocardial infarction.
The study sample included 1,152 non smokers, 1,152 prior smokers, and 570 current smokers at the time of ischaemic stroke. Amongst those current smokers, 162 had quit by 3 months after ischaemic stroke and 408 were persistent smokers.
The mean age of study participants was between 57 and 64.
As a general finding, researchers note that the current smokers were younger than the past or non smokers, more women were non smokers than current or former smokers.
The former smokers had an average smoking history of 24 years, which was shorter than the current smokers which averaged between 32 to 35 years.
Amongst the current smokers, the proportion of persistent smokers decreased throughout the follow-up, from 71.6 per cent at 3 months, to 68.3 per cent, 67.3 per cent, and 66 per cent at, 6, 12, and 18 months, respectively.
However, a small percentage of patients who had quit smoking by 3 months had resumed smoking by 6 (14.2 per cent) or 12 (20.4 per cent) months.
The researchers found that the primary outcome of MACE occurred among 14.2 per cent of the never smokers, 16.2 per cent of the former smokers, 12.4 per cent of the current smokers who quit by 3 months, and 18.4 per cent of the persistent smokers.
When compared with those who had never smoked, persistent smoking was linked with increased risk for MACE.
In a subgroup analysis, age was found to have a significant interaction for the primary outcome, in which increased risk from MACE among persistent smokers compared with non smokers was only significant among patients younger than 60, but not for those older than 60.
The researchers state: “We demonstrated an association between persistent smoking after stroke and higher risk of composite outcome of death, stroke, and myocardial infarction.”
