Use of Warfarin for Atrial Fibrillation Linked To Increased Risk of Dementia

Warfarin is used for the purpose of preventing the clotting of blood and has proved to be a lifesaving drug for a variety of conditions, atrial fibrillation being one of them. Atrial fibrillation (AF) is a type of arrhythmia in which the heart beat becomes quite irregular and abnormally fast. 

The signs and symptoms of atrial fibrillation include difficulty in breathing, palpitations, dizziness and fatigue etc. The condition is associated with the risk of blood clot formation within heart which can result in stroke. Warfarin, by inhibiting the formation of blood clots, dramatically reduces the risk of stroke, saving the life of the patients. 

A recently held study has pointed out that over time, the blood thinning property of warfarin can increase the likelihood of bleeding within the brain and can lead to dementia. 

Warfarin May Cause Dementia

The study was carried out by Dr. T. Jared Bunch and fellow researchers at Intermountain Medical Center Heart Institute in Salt Lake City, UT. They looked at the data of 10,000 patients taking warfarin in order to look into the possible relationship between warfarin use, dementia and atrial fibrillation. The research findings were later presented at the Heart Rhythm Society's 37th Annual Scientific Session. 
Majority of the patients taking warfarin were taking it for the treatment of atrial fibrillation. However, some of them were using warfarin for other blood clot related conditions like thromboembolism and valvular heart diseases. None of the study subjects had any previous history of dementia. 

The subjects were followed up for 7 years. The data obtained after 7 years interval was quite disturbing, revealing that 5.8 percent of the people taking warfarin for atrial fibrillation had dementia as compared to a mere 1.6 percent people taking warfarin for other conditions. 
People using warfarin for AF for long term were found to be more likely to develop vascular dementia and eventually, Alzheimer’s disease, as compared to people taking it for non-AF causes. 

Warfarin and the Threats Associated With It

The administration of warfarin is quite tricky. One must weigh the potential benefits and risks associated with it before prescribing it. The response to warfarin varies between different patients. Besides, finding the precise dose can turn out to be a time consuming process since the onset of action for warfarin occurs late. 

Previously it was thought that the risk of dementia in patients on long term warfarin therapy was dose dependent.  Now it is known that the risk of dementia increases irrespective of the dose of warfarin. This study is the first of its kind to show the risk of cognitive decline associated with long term anticoagulation with warfarin. 

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The Future Prospects

According to Dr. Bunch, the lead researcher, the results are going to have a significant impact on warfarin administration in future. He believes that it may lead to formulation of guidelines that will allow prescription of warfarin only when no other suitable alternative exists. 
He went on to advise that the use of other anticoagulant drugs like Aspirin should also be avoided. When it becomes altogether impossible to avoid the use of blood thinning drugs, newer and safer drugs should be used instead of warfarin. 

Since warfarin is a widely used drug, the findings of this study are likely to pave way for further research into the safety of this drug. 

Women With Atrial Fibrillation At Risk of Developing Cancer

A recent study has found that women suffering from atrial fibrillation are at high risk of developing cancer, particularly that of the colon. 
Atrial fibrillation (AF) is one of the most common cardiovascular events in which the heart rate becomes quite irregular and fast. The condition is linked with serious cardiovascular complications. However, the risk of non-cardiac complications is also quite high in AF patients and among them, malignant tumors have been found to be the most common. 

The study was carried out by David Conen, MD, MPH, of the University Hospital in Basel, Switzerland, and his fellow researchers. The results of the study were subsequently published in JAMA Cardiology. This long term study spanned a period of 20 years from 1993 to 2013. 

During the course of the study, the researchers followed 34, 691 women aged 45 years and above. At the start of the study, none of the women had any previous history of atrial fibrillation and cancer. This prospective study is the first of its kind aimed at studying the long term association between atrial fibrillation and cancer.

Atrial Fibrillation and Cancer Are Correlated

During the follow up study, it was found that 4% of the study subjects developed atrial fibrillation whereas 15% of the women developed cancer. Atrial fibrillation was found to be a major risk factor for the development of cancer in age-adjusted and multivariable-adjusted study models. 

The researchers particularly investigated into lung, breast, and colon cancer. According to the lead researcher Dr.Conen, the strongest association was found between atrial fibrillation and colon cancer. The study established that the number of patients of atrial fibrillation dying of non-AF causes is way higher than was previously thought. 

The risk of development of cancer in patients suffering from atrial fibrillation was highest one year after the diagnosis of AF. On the contrary, in the women suffering from cancer, the risk of atrial fibrillation was present only during the initial three months after the diagnosis of cancer. 

The researchers stipulated that hidden risk factors may underlie the association between AF and cancers. The exact mechanism by which atrial fibrillation increases the risk of cancer in women is as yet, unknown. One plausible explanation for it can be shared risk factors. This view is supported by the fact that new onset cancer and new onset AF share a common risk factor profile, particularly the body mass index (BMI) 

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On the other hand, AF may be the primary result of any systemic pathology which enhances the risk of both these conditions in women. Inflammatory processes and oxidative stress can be the underlying mechanism. Formation of blood clots can be another causative factor since both these conditions give rise to a pro-thrombotic state. 

This study has opened doors for new research into the precise mechanisms by which the risk of cancers increases in women with atrial fibrillation. It can lead to risk factor control for the prevention of cancer in such patients and formulation of effective preventive strategies for cancer control.