NEW YORK (Reuters Health) – When asymptomatic patients with a supratherapeutic INR are seen in the emergency department, can they be treated as outpatients or should they be admitted to the hospital? There’s very little published evidence to help with that decision, researchers found, but what there is does not indicate that the management approach affects outcomes.

Dr. Michael Levine, with Banner Good Samaritan Medical Center in Phoenix, Arizona and colleagues note in the Annals of Emergency Medicine online May 30 that when patients receiving warfarin are seen in the emergency department, more than 25% are found to have a supratherapeutic INR. Such patients are often admitted to a hospital, but there would be advantages to patients and hospitals if this could be safely avoided.

The team conducted a literature review to look at evidence for or against outpatient treatment of asymptomatic patients with a supratherapeutic INR. They found no randomized trials comparing inpatient versus outpatient management, but several studies examined outcomes after outpatient treatment.

The authors summarize four of the most relevant studies in their report. For example, in one study of 89 patients with an INR of more than 10, 75 of the patients were considered appropriate for outpatient therapy. Only three of the patients developed significant bleeding within 3 days, and these were in a group that did not receive vitamin K.

In another study, 114 patients with an INR greater than 6 were followed as outpatients and were not treated with vitamin K. Five patients had major bleeding within the first 2 weeks. A third study found that when 1043 patients with an INR between 5 and 10 were treated with vitamin K as outpatients, one patient had a major bleeding episode within 30 days whereas 6 patients experienced a thromboembolic event.

“According to this review, it is certainly within the standard of care to manage patients with an asymptomatic, supratherapeutic INR as outpatients,” Dr. Levine and colleagues conclude.

They add, “We were unable to find any studies that support a reduced risk of warfarin-associated bleeding caused by rapid INR reversal or inpatient admission.”

Ann Emerg Med 2011.