Patients taking anticoagulants for atrial fibrillation were at a much lower risk of developing dementia than those who were not, a new study has revealed.
The retrospective study, the largest to date to look at the association between the drugs and dementia, examined data for just over 444,000 Swedish patients who had an atrial fibrillation diagnosis from a hospital. Just over half of the patients were not taking any oral anticoagulant treatment, and the remaining patients were taking either warfarin or a NOAC.
The researchers from the Danderyd University Hospital, Stockholm, found that patients taking anticoagulants had a 29% reduced risk of developing dementia, which rose to a 48% reduced risk when they looked at the time period during which the patients took the drugs.
They noted that the protective effect against dementia was greater the sooner oral anticoagulant treatment was started.
They said in the paper, which was published in the European Heart Journal: ‘Our results strongly suggest that OAC treatment protects against dementia in AF. In order to prove this assumption, randomised placebo controlled trials would be needed, but as previously pointed out, such studies cannot be done because of ethical reasons. It is not possible to give placebo to AF patients and then wait for dementia or stroke to occur.
‘Therefore, we have to do the second best, which is to use the information in population-wide health databases for retrospective studies while trying to control for biases and confounders the best we can.’
Dr Leif Friberg, lead author and associate professor of cardiology at the Karolinska Insitute, commented: ‘Patients start on oral anticoagulation for stroke prevention but they stop after a few years at an alarmingly high rate. In the first year, approximately 15% stop taking the drugs, then approximately 10% each year. In this study we found that only 54% of patients were on oral anticoagulant treatment.
‘If you know that AF eats away your brain at a slow but steady pace and that you can prevent it by staying on treatment, I think most AF patients would find this a very strong argument for continuing treatment.’