A blood thinner for the heart may also be gentle on the memory
What happened
A large Swedish study has found that people living with both Alzheimer's disease and an irregular heartbeat may lose their memory slightly more slowly if they take a newer type of blood thinner. The research was published in the European Heart Journal on 18 September 2026. It was led by scientists at the Karolinska Institutet in Sweden. The team looked at records for 7,308 people. Every one of them had two conditions at the same time: Alzheimer's disease, and atrial fibrillation. Atrial fibrillation is often shortened to AF. It means the heart beats in an irregular way. It is common as people get older. AF matters because it makes blood more likely to form a clot inside the heart. If that clot travels to the brain, it causes a stroke. To lower that risk, doctors prescribe blood thinners, properly called anticoagulants. There are two main kinds in use. The older one is warfarin, which has been used for decades. The newer ones are known as NOACs, short for non-vitamin K oral anticoagulants. Apixaban and rivaroxaban are examples. The researchers used a national database called SveDem. This is Sweden's register of people diagnosed with dementia. It has followed patients for years, which is what made the study possible. They sorted people into three carefully matched groups. One group was taking a newer NOAC. One was taking warfarin. One was taking no blood thinner at all. Matching the groups means the researchers tried to compare people who were otherwise as similar as possible, in age, health and other factors. Then they tracked how each group's memory changed over time.
Why this matters
Two conditions that often sit together have usually been treated as separate problems. The heart doctor thinks about stroke risk. The memory clinic thinks about dementia. This study looks at both at once. That is unusual, and it is useful. Roughly one in three people with dementia also has atrial fibrillation, so this is not a rare combination. It describes a great many families. There is also a practical worry behind all of this. Blood thinners work by making it harder for blood to clot. That is the point of them. But it also means bleeding is more likely, including bleeding in the brain. Because of that, some people with dementia are never offered a blood thinner, or are taken off one, because the risks feel too high. So a study suggesting that a particular type of blood thinner is linked to slower memory decline, as well as fewer strokes, is worth paying attention to. It adds something to a decision that families and doctors often find genuinely difficult. It is also a reminder of something easy to forget. A medicine prescribed for one part of the body does not stay in that part of the body. A drug for the heart travels to the brain too.
What the evidence actually says
Here is where care is needed, because the headline is more exciting than the numbers. Memory was measured using the Mini-Mental State Examination, or MMSE. It is a short test scored out of 30. Higher is better. People taking a newer NOAC declined by about 0.23 points a year less than people taking no blood thinner. Compared with warfarin, the difference was about 0.21 points a year. That is small. On a test scored out of 30, a fifth of one point over a whole year is not something a family would notice. The researchers are clear about this. Maria Eriksdotter, one of the senior scientists, said: "The difference is modest for an individual patient from one year to the next, but over a longer period even such an effect could influence how cognitive function develops." That is the honest version. Small each year, possibly meaningful if it builds up over several years. Possibly. The study found other things too, and some were less ambiguous. People on newer NOACs had lower rates of death, stroke, blood clots and fractures. People on warfarin had a higher risk of serious bleeding. Now the important limitation. This was an observational study. That means the researchers watched what happened to people who were already taking these medicines. They did not randomly assign anyone to a treatment. That matters, because people who are prescribed newer blood thinners may differ from those who are not, in ways the researchers could not fully measure. Someone frailer, or further along with their dementia, might be less likely to be started on a blood thinner in the first place. The study team matched the groups to reduce this problem, but matching cannot remove it completely. So this study shows a link. It does not prove that the medicine caused the slower decline. The researchers say so themselves. They suggest a possible explanation, that better blood flow and less small-scale damage in the brain might help, but that remains a theory to be tested. One more point. This study was carried out in Sweden, in people already diagnosed with Alzheimer's and AF. It does not tell us anything about whether blood thinners protect memory in people who do not have these conditions.
Qurexa perspective
There is one genuinely practical thread here, and it is about taking medicines regularly rather than about which medicine is best. Anticoagulants only do their job if they are taken as prescribed. Missed doses reduce the protection against stroke. For someone living with memory problems, remembering a daily tablet is exactly the thing that becomes hard, and it often becomes hard gradually, without anyone noticing at first. This is the everyday problem behind a lot of our work. We deliver prescriptions across Lincolnshire and support people with medication adherence, including families managing tablets for an older relative. Simple things help: a dosette box, a repeat prescription that arrives before the last one runs out, one routine rather than several. None of that changes which medicine is right for someone. That is a conversation for a GP or a pharmacist, and this study is not a reason to request a switch. But if the tablets are already the right ones, taking them consistently is the part that is within reach.
Practical advice
If you or someone you care for is affected, here is what is reasonable to do. Do not change anything on your own. Stopping a blood thinner suddenly can raise the risk of a stroke sharply. This is one of the clearest rules in medicine. If you have concerns, raise them, but keep taking the tablets while you do. If you already take a newer blood thinner, this study is mildly reassuring. There is nothing here that should worry you. If you take warfarin, do not assume you are on the wrong drug. Warfarin is still the right choice for some people, including those with certain heart valves, and switching is not always possible or safe. Your doctor will have had a reason. If you or a relative has atrial fibrillation and dementia and is not on any blood thinner, it is fair to ask why at the next appointment. There may well be a good reason. But it is a reasonable question. A useful way to ask is simply: what is the plan for stroke prevention, and when will it next be reviewed? Watch for signs of bleeding and report them. Unusual bruising, blood in urine or stools, black tarry stools, nosebleeds that will not stop, or a bad headache after a bump to the head all need prompt medical advice. Keep a current list of all medicines, including anything bought over the counter. Some painkillers, including ibuprofen and aspirin, interact with blood thinners. Ask a pharmacist before buying anything new. And if remembering doses is becoming difficult, say so early. There are straightforward ways to make it easier, and they work better when put in place before things slip.
What to know
A Swedish study of 7,308 people with both Alzheimer's disease and atrial fibrillation found that those taking newer blood thinners, known as NOACs, declined about 0.2 points a year more slowly on a 30-point memory test than those taking warfarin or no blood thinner. The same group also had lower rates of death, stroke, clots and fractures, while warfarin was linked to more serious bleeding. The memory difference is small in any one year. It might matter if it accumulates, but that has not been shown. The study was observational, so it cannot prove the medicine caused the effect. Nobody should change or stop a blood thinner because of this research. If you have questions, ask your GP or pharmacist and keep taking your tablets in the meantime. Sources: European Heart Journal, "Oral anticoagulants, cognition, and clinical outcomes in atrial fibrillation and Alzheimer's disease: a Swedish nationwide study" by Nanbo Zhu and colleagues, 18 September 2026, DOI 10.1093/eurheartj/ehag584, https://academic.oup.com/eurheartj ; ScienceDaily, "These blood thinners may have an unexpected benefit for Alzheimer's patients", 18 September 2026, https://www.sciencedaily.com/releases/2026/09/260917003732.htm ; Karolinska Institutet (SveDem, the Swedish Registry for Cognitive/Dementia Disorders), https://www.svedem.se This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional. Never start, stop or change a prescribed medicine without speaking to the person who prescribes it.
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