Anticoagulation Prescription in the ED May Boost Later Use

Sending older patients with A-fib home from the emergency department (ED) with a prescription for oral anticoagulation appears to have a substantial impact on whether they’ll still be taking the medication 6 months to a year later, Canadian researchers have found.

Fewer than one in every five patients received a prescription before they were sent home, but those who did were more likely than those who didn’t to fill a prescription 6 months later (67.8% vs 37.2%). A difference, though attenuated, persisted at 1 year (63.7% vs 40.5%; P < 0.001 for both).

Lead author Clare Atzema, MD (Sunnybrook Health Sciences Centre, Toronto, Canada), told TCTMD that emergency physicians are often afraid to prescribe chronic medications to patients because they’re not likely to be able to follow up and make sure treatment is well tolerated. “It’s asking quite a bit for a physician who’s never going to see the patient again to start a chronic medication,” Atzema said.

But this study, published in the December 9, 2019, issue of CMAJ, “gives us some evidence that actually it’s a good thing to do,” she said.

ED Visit as an Opportunity

Patients with A-fib, in whom oral anticoagulation is generally underused, often make their way to the ED because of palpitations, shortness of breath, and chest pain, Atzema noted. “We know that a lot of them are not getting the appropriate anticoagulation, so that creates an opportunity for us to prescribe,” she said.

I think in the ER we get patients when they’re frightened, when they’re stressed, and we probably have a teachable moment, which I think is kind of an amazing thing. Clare Atzema

Many emergency physicians are hesitant to prescribe oral anticoagulation and other chronic medications, however, both because of the desire to avoid delays in treating other patients in the ED and because of the inability to provide continuity of care after the patient goes home, Atzema explained. “There’s a big argument that emergency care is for acute illness and then there’s preventative care, which is done within primary care.”

There’s also a lack of evidence showing that there is a benefit from prescribing chronic medications in the ED, she said. “My thinking was there probably is. I think in the ER we get patients when they’re frightened, when they’re stressed, and we probably have a teachable moment, which I think is kind of an amazing thing that we have and we don’t always capitalize on.”

Atzema and her colleagues looked into whether getting a prescription for oral anticoagulation into the hands of patients with A-fib while they were in the ED made a difference later on. They examined retrospective data on 2,132 patients 65 or older who received a primary diagnosis of atrial fibrillation or flutter at 15 EDs in the province of Ontario between April 2009 and March 2014. The analysis included only patients who were discharged from the ED and were not already taking oral anticoagulation.

Overall, 18.9% of patients were given a prescription for oral anticoagulation before they were sent home; that rate varied widely from 7.3% to 38.2% across hospitals.

After inverse probability of treatment weighting based on propensity score, receipt of an ED prescription was associated with a 30.6% absolute increase in rate of prescriptions filled at 6 months and a 23.2% absolute increase at 1 year, with numbers needed to treat (NNTs) of 3 and 4, respectively, at the two time points. Adherence based on the proportion of days covered by a prescription over the first year was higher in patients who received a prescription in the ED as well.

Rates of all-cause mortality, stroke, and bleeding leading to hospital admission did not differ based on whether patients received a prescription in the ED, but Atzema noted that the study was underpowered to detect such differences because of the short duration of follow-up and the small number of patients. These patients also represent a group with very low risk because they were sent home from the ED and not admitted to the hospital, she pointed out.

Despite the lack of difference in clinical outcomes in this study, the authors estimate that getting more patients on oral anticoagulation by giving them a prescription in the ED could have a potentially large impact on how patients fare.

“To prevent one stroke at 1 year, the NNT with oral anticoagulants is 1.7; therefore, the NNT for oral anticoagulant prescriptions in the emergency department to prevent a stroke is about 7,” they write. “By comparison, the NNT for statins to prevent nonfatal myocardial infarction in patients with a history of heart disease is 39.”

Short-term Prescription May Be a Solution

Commenting for TCTMD, Deborah Diercks, MD (UT Southwestern Medical Center, Dallas, TX), said she wasn’t surprised to see that giving a prescription for oral anticoagulation in the ED was associated with greater use after discharge, as earlier studies have hinted at the phenomenon for other chronic medications. The lack of a difference in clinical outcomes also wasn’t unexpected, she said, because of the short duration of the study period and the size of the patient population.

What the study does is “reinforce that we do need to be doing a risk assessment for the need of anticoagulation,” Diercks said.

“That has become in many ways an expectation in the emergency department, and although there clearly hasn’t been rapid adoption of thinking in that manner, I think it’s something that we’re going to have to take on as a specialty,” she continued. “The decision to initiate anticoagulation is really easy once you utilize the CHA₂DS₂-VASc score and [other] risk scores that are out there.”

She added that prior studies have shown that simple reminders can help increase the rate of prescriptions in the ED. “What I take from this study is that we need to continue to move forward with identifying these patients and actually initiating therapy in the emergency department because it is an opportunity to initiate a therapy that could have significant long-term advantages to the patient,” Diercks said.

As for potential obstacles to prescriptions in the ED, Diercks pointed to a perception among some emergency physicians that it isn’t their job to prescribe chronic medications like oral anticoagulants and to a bias bred by a greater familiarity in the emergency medicine field with the harms of these drugs. “And then I think there probably is some lack of knowledge about the importance and how to actually stratify these patients,” she said.

A potential solution suggested by Atzema to overcome some of these barriers may be use of short-term prescriptions for oral anticoagulation in the ED, just enough to allow patients to check in with their preferred primary care physician or cardiologist to assess the need for longer-term therapy.

“It’s much more comfortable putting somebody on a medication, especially if you choose warfarin, for 7 days and not for a prolonged period of time because the perceived risk in that 7 days is much less than [during] a longer prescription, and then if the patient doesn’t get follow-up in that time, the person prescribing it doesn’t feel at risk,” Diercks commented.

This short-term approach, giving a 7- or 30-day prescription, “takes away a lot of the fear for emerg docs,” Atzema said. If patients don’t see anyone about extending the prescription after leaving the ED, “then the prescription ends, the risk of bleeding ends, and you did what you could and that’s not on you. You tried. And I think for an emerg doc, that’s a really reassuring message.”