Men who live alone struggle with taking warfarin

Men who live on their own—but not women—struggle to take warfarin as directed, according to research presented Sept. 2 at the ESC Congress in Paris.

Warfarin, a blood thinning drug, is a common prescription for heart patients, study author Anders N. Bonde said in a release—but it can also be a tricky one. Too little warfarin could allow for clotting and too much risks major bleeding, so continuous blood monitoring with international normalized ratio (INR) measurements is required to keep patients’ safety in check.

Quality of INR control is typically measured as time in therapeutic range (TTR), or the percentage of time a patient’s blood levels of warfarin are optimal for preventing stroke and bleeding. ESC guidelines recommend being in the therapeutic range at least 70% of the time, which can be difficult when patients also have to navigate the multiple food and drug interactions that come hand-in-hand with a warfarin prescription.

Bonde and his team recruited 4,772 atrial fibrillation patients from Danish registries for their study, all of whom had six months of continuous warfarin use and INR monitoring under their belts. The researchers stratified the pool by sex and living situation and calculated TTR for men living alone, men cohabitating, women living alone and women cohabitating. 

The average TTR in men who lived alone was 57%—3.6% lower than in cohabitating men even after adjusting for other factors that could affect TTR. Women who lived alone also struggled with a lower TTR than cohabitating women, but after adjustment the 0.2% difference was negligible. 

“‘Ask my wife’ is a common reply among older men to questions about their medication, disease and treatment,” Bonde said. “Our study suggests that when it comes to anticoagulation control, men are more dependent on their partner than women.”

Women who live alone typically have better relationships with their kids or a wider support network that can help them manage their warfarin regimen, he said. On the other hand, men struggle more with divorce and are more prone to alcohol abuse than their female counterparts.

“Cohabitation status was a strong and important predictor for TTR among men, but not among women,” Bonde said. “Men who live on their own may need extra support to use warfarin, such as education, home visits, telephone contracts or additional follow-up visits. They might also consider using a newer type of drug, a non-vitamin K antagonist oral anticoagulant, which is easier to manage and has fewer interactions with food and drugs compared to warfarin.”