Sometimes it's a weekly trip to the clinic for Patricia Slattery, sometimes it's every two. At one point, she was visiting the doctor three times a week to get her blood drawn.
About three years ago, Slattery was diagnosed with deep venous thrombosis, a condition in which blood clots form in deep veins in the body. Doctors put her on warfarin, an anticoagulant that prevents blood clots. Those on the medicine must tightly monitor their blood to make sure they are getting an adequate, but safe, dose of the drug.
The result is an intricate, daily balancing act for these patients.
"It's a bit of a pain to get checked, but I can't complain because the medicine saved my legs," said Slattery, a 69-year-old resident of Baltimore, Md. "It's an important part of my life now, so if I have anything planned and then I have to suddenly get my blood taken, I'll cancel."
Warfarin is the most widely prescribed blood thinner in the United States; about 2 million people take the drug on any given day.
While the monitoring usually takes place in a doctor's office, a new study from the Veterans Affairs Medical Center found that an at-home weekly test may be just as safe and effective as a monthly blood draw in the doctor's office.
"We need strategies to make warfarin anticoagulation easier and safer," said Dr. David Matchar, co-author of the study and director of the Health Services Research Field Program at Duke-NUS Medical School in Singapore. "The availability of devices that can provide results comparable to high-quality clinic care should encourage people at high stroke risk and their doctors to use this treatment, and to be assured that they can use it well."
About a year ago, Rick Pero was diagnosed with atrial fibrillation, a condition where the heart beats irregularly, and Pero was also put on warfarin. Now, every two weeks, Pero leaves work early to drive 45 minutes to a health center to get his finger pricked.
"If I had a self-test that I could use at home, it would save me a lot of time, especially since I have to use an hour of sick time every time I leave work to get my blood drawn," said Pero, a maintenance director in Wolfeboro, N.H.
Patricia Slattery agreed that a home test would make life more convenient.
"If I had a monitoring system in my own possession, it'd be much easier, and I could get the results to my doctor even quicker than he gets them now," said Slattery.
The study, published on Wednesday in the New England Journal of Medicine, involved 2,922 patients who were taking warfarin and capable of using a self-testing home device, similar to a finger stick glucose test for diabetic patients. It's important to note that, in past studies, weekly self-testing proved to be better at reducing the risk of stroke, death, and major bleeding events than a monthly doctor's visit. But after two years of follow-up, this study showed that the self-test and the clinic tests were similar in result.
"Since we did not find a difference in these events between the two testing groups, we were surprised by the results," said Dr. Rowena Dolor, co-author of the study and assistant professor in the internal medicine division at Duke University Medical Center in Durham, N.C. "This study was conducted within high-quality anticoagulation clinics and the lack of the difference between office testing and home testing may be due to the high level of anticoagulation care received in the VA setting."