Self-Monitoring of Blood Drug Helps Patients

Fewer problems, lower death rate, researchers found

THURSDAY, Feb. 2, 2006 (HealthDay News) -- People who take the anti-clotting medication warfarin get substantial benefits if they monitor their own blood levels rather than have a laboratory do it for them, British researchers report.

An analysis of 14 controlled trials found that self-monitoring led to a 55 percent reduction in harmful clotting events, a 39 percent lower death rate from all causes and a 35 percent reduction in major bleeding crises, as compared to laboratory monitoring, according to a study that appears in the Feb. 3 issue of The Lancet by physicians at the University of Oxford.

The study was intended to fill a knowledge gap, the researchers wrote. "Published guidelines state that there are no reliable clinical-outcome data in any of the published studies to lend support to its [self-monitoring] use," they noted.

Their analysis showed otherwise: "Self-management improves the quality of oral anticoagulation," the report said.

The study was initially intended simply to show that self-monitoring was safe, said study author Dr. Carl Heneghan, a clinical research fellow at Oxford. The finding of substantial benefit came as something of a surprise.

"Each of the trials alone was not statistically significant, but combining them showed that you get a benefit in terms of mortality," he said.

Self-monitoring for warfarin is basically the same as what people with diabetes do when they check their blood sugar levels, Henegan said. "It offers a sense of freedom, of not being tied to a clinic," he noted.

Warfarin, best known as the prescription drug Coumadin, is notoriously difficult to manage, requiring frequent blood tests to be sure that the ability of the blood to clot is within the normal range. People taking the drug often have to take tests every few weeks, or even weekly, for years on end.

Self-monitoring equipment has been approved for use in the United States by the U.S. Food and Drug Administration, yet fewer than 1 percent of physicians allow their patients to do their own monitoring, noted Gary Liska, director of the disease management group of Quality Assured Services, a Florida company that markets three monitor models.

One reason is that Medicare pays for such equipment only for people with artificial heart valves, Liska said. But the drug can be taken for a number of other reasons, such as control of the abnormal heartbeat called atrial fibrillation.

There's is also "fear of loss of control of patients," Liska said. "We feel that in reality the opposite is true, that patients have better control than ever before."

Another issue is fear of malpractice suits should something go wrong with self-monitoring. There is a high chance of a harmful interaction with another drug for warfarin, and many of the people who take it are elderly and are taking a number of other medications, Liska said.

The journal report noted some other deterring factors, such as the intensive patient training required and the high cost of test strips.

Once the technique is learned, a self-monitoring test requires only a fingerstick, similar to that done by someone with diabetes to measure blood sugar levels, Liska said. If the reading is outside the range set by the doctor, the patient can call the physician for instructions about changing the dose.

But when it comes to allowing patients to monitor their blood clotting level, "many doctors seem to have a roadblock in their minds," he said.

More information

More about warfarin is provided by the National Library of Medicine.

SOURCES: Carl Heneghan, M.D., clinical research fellow, Oxford University, England; Gary Liska, director, disease management group, Quality Assured Services, Melbourne, Fla.; Feb. 4, 2006, The Lancet
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