ESOC 2024 | Income and education level significantly impact stroke mortality risk

Being a rehab physician, I had a gut feeling let’s put it that way, that people bring with them their history… meaning their comorbidities but also their living condition that has an impact on outcome. We have students doing semester work with us in order to get their graduation and this student came up to me and he said “how come I’m doing fine where other people that are born or live in the same area, that I went to school with, they’re not as successful?”. So we decided to see what we could look at regarding these softer areas that we’re not very often as physicians looking into, like where people live, their living conditions, their income, their education, where they’re born, etc…

So we have local stroke quality register in Gothenburg, Sweden where we have almost 7,000 patients that have entered data regarding stroke severity, comorbidities, when they came to the hospital, physical activity level, etc. We combined those data with data from Riks-Stroke, the Swedish national quality register that has a long-term follow-up but we also went to the National Board of Health and Welfare because they have data on all specialized health care that a patient has had at a hospital, whether it’s inpatient or outpatient. So we got that data as well for these patients in order to look at other comorbidities and make for instance a Charlson Comorbidity Index. Also prescribed drugs that they’ve taken up to two years prior to the stroke and then also afterwards. Then we combine that with data from Statistics Sweden regarding the household income the last two years prior to the stroke, also where people are born, level of education, etc. The National Board of Health and Welfare merged all these data files, they were merged using personal identification numbers so they could merge them and we were sent pseudonymized data back so we could not identify anything so it was ethically completely safe.

So we looked at these data and we could see that yes the traditional risk factors such as atrial fibrillation, diabetes, yes they do of course have an effect regarding mortality after stroke, but we were specifically interested in the social demographic data such as age, gender, income, where you live, educational level, and where you were born. We divided our city because our city has around 800,000 catchment areas. It contains both rural areas, archipelago with fishing villages, as well as high rises and also what the police called ‘blue light’ areas, eight of those areas, that are socially insecure and they don’t really like to go in there that much. So we looked at to see who lived in those more dangerous areas and we looked at them compared to the rest of the people and then we looked at these different risk factors like different quintiles for income, we looked at the living areas, we looked at education level and country of birth as well as sex and age.

What we could see was that higher income and higher education was a positive factor. We could not see that much difference depending on living quarters because there were not enough people living in the poor areas so we can’t say that it’s not a factor, but we couldn’t really analyze it very much. We could see that things like being poor is a risk factor of having a poor outcome after having a stroke and this is in a country where healthcare is free. It’s tax finance. We have quite a small width when it comes to income variation. And also we have three hospitals and all people just go in and the ambulance drives to the hospital that is closest or if you need thrombectomy they drive to one, so that’s given to everyone no matter your income or the money you have in your wallet. So what we could see was that still income had an influence on outcome. We think that this has to do with that… we know the wealthier people often have a better overall health status. That might sound strange when it’s a tax finance system but going and seeing the doctor they consume more healthcare compared to the poor people, we know that from statistics, and it means that if you’re going to see the doctor you usually need to take time off from work which means that there’s a loss of income and if you have a very low income those Swedish crowns are the ones that you actually need. We also know that that poorer people often have not as good eating habits, they have also worse oral health because it’s also more expensive to go to the dentist, there are a higher number of smokers, and they follow the recommendations when it comes to prescriptions and so on less than the high-income people with high education.

I think that what we need to realize is that we as physicians we cannot fix the whole society but we can point out that these are problems that are outside the healthcare system but has an impact on the healthcare system. We also need to realize that when we give people folders or prescribe drugs, it’s not only just handing over the paper it’s also making sure that the person who you hand over to actually understands why they’re asked to do this, why they should stop smoking, why they need to take these pills or whatever, or change their lifestyle behavior. I think that is a challenge for us to understand that we need to differentiate our message depending on who’s on the other side of the table.

We’re waiting on an ethical approval to get 4-year data from Riks-Stroke and then we also want to merge it with the national cohort because I mean, 7000 is fine but we have around 25,000 strokes per year in Sweden which is not a lot but it’s still quite a number. With four years, we’ll have more people and we will be able to explore this further because I think that even in a tax finance country like Sweden this is a problem and we do know that we have around 1/5 of the population is born outside Sweden or outside Europe so there is a diversity in the population and that requires that we change our way of working with primary prevention.