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Patient Safety Tip of the Week
January 17, 2023
Patient Safety with
NOAC’s and DOAC’s
Oral anticoagulants
are the mainstay for prevention of stroke in patients with atrial fibrillation.
With the advent of non-vitamin K antagonist oral anticoagulants (NOAC’s)/direct
oral anticoagulants (DOAC’s), many of the safety concerns we had when using
warfarin were expected to be bypassed. These new oral anticoagulants no longer
needed to be titrated to a lab value and had fewer drug and food interactions
than seen with warfarin. And clinical trials of most of these newer agents
showed efficacy at least as good as warfarin along with fewer serious bleeding
consequences. So, combining simpler regimens with better safety profiles has
led to greater uptake of these agents in patients with atrial fibrillation, including
their use in patients in whom we’d previously have been wary of using warfarin.
Ko et al. (Ko
2022) looked at trends between 2010 and 2020 in initiation of oral
anticoagulants in Medicare Advantage patients age 65 and older with atrial
fibrillation. Indeed, rates improved from 20.2% to 32.9% (with the rate of DOAC
uptake increasing from 1.1% to 30.9%). Over the same period, warfarin
initiation decreased from 19.1% to 2.0%. Among patients who were initiated on oral
anticoagulants, there was an increase in DOAC uptake from 5.4% in 2010 to 93.9%
in 2020. Moreover, nonadherence rates decreased from 52.2% to 39.0%. But patients
with dementia, frailty, and anemia were still less likely than patients without
those conditions to have an oral anticoagulant initiated. The authors conclude
that, despite the improved rates of oral anticoagulation, such management has remained
suboptimal. They call for additional strategies to improve stroke prophylaxis
in all older adults with atrial fibrillation including those with coexisting
dementia, frailty, and anemia.
A recent Medscape article
(Wajngarten
2022) summarized several recent studies on safety issues with NOAC’s/DOAC’s
in patients with atrial fibrillation. He cited a a
systematic review and meta-analysis by Caso et al. (Caso
2022) that found frequent inappropriate dosing of non-vitamin K antagonist
oral anticoagulants (NOAC’s) in patients with atrial fibrillation. Compared with recommended DOAC dosing, overdosing
was associated with an increased risk of major bleeding, as expected. Underdosing
was associated with a null effect on stroke outcomes and bleeding outcomes (the
latter unexpected) but an increased risk of all-cause mortality. Increased
age, history of minor bleeds, hypertension, congestive heart failure and low
creatine clearance were associated with an increased risk of underdosing.
Physicians have been reluctant to use anticoagulants in
patients at risk for falls. We’ve done several columns on the risk of
intracranial hemorrhage after head trauma in patients taking oral anticoagulants,
with studies offering mixed conclusions. Wajngarten
cited a new Canadian study (Grewal 2021) that
found patients on warfarin seen in the emergency department with a head injury
had higher relative risks of intracranial hemorrhage than matched patients on a
DOAC and patients not on anticoagulation, respectively. The risk of intracranial
hemorrhage for patients on a DOAC was not significantly different compared with
no anticoagulation.
Another patient
group in which anticoagulant prescription has been low is those with frailty. Wajngarten cited a recent study (Kim 2022)
that showed in frail patients with AF, oral anticoagulant treatment was
associated with a positive net clinical outcome. DOAC’s provided lower
incidences of stroke, bleeding, and mortality, compared with warfarin.
Taken together, these studies suggest that many of the
barriers to prescribing oral anticoagulants in patients with atrial
fibrillation still exist, despite evidence that their use in such patients might
be justified, particularly when NOAC’s/DOAC’s are used rather than warfarin.
Some of our previous
columns on head trauma in the anticoagulated patient:
April 16, 2007 “Falls
With Injury”
July 17, 2007 “Falls
in Patients on Coumadin or Heparin or Other Anticoagulants”
June 5, 2012 “Minor Head Trauma in the Anticoagulated
Patient”.
July 8, 2014 “Update: Minor Head Trauma in the
Anticoagulated Patient”
August 21, 2018 “Delayed
CT Scan in the Anticoagulated Patient”
September 21, 2021 “Repeat CT in Anticoagulated
Patients After Minor Head Trauma Not Cost-Effective”
December 14, 2021 “Delayed Hemorrhage After
Head Trauma in Anticoagulated Patients”
References:
Ko D, Lin KJ, Bessette LG, et al. Trends in Use of Oral
Anticoagulants in Older Adults With Newly Diagnosed
Atrial Fibrillation, 2010-2020. JAMA Netw Open 2022; 5(11):
e2242964
https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2798659
Wajngarten M. Oral Anticoagulant
Mistakes to Avoid in Older Adults With AF. Medscape Medical News 2022; December 23, 2022
https://www.medscape.com/viewarticle/986128?src=WNL_dne1_221226_MSCPEDIT&uac=14695HV&impID=5032296
Caso V, de Groot JR, Sanmartin
Fernandez M, et al. Outcomes and drivers of inappropriate dosing of non-vitamin
K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation:
a systematic review and meta-analysis. Heart. 2022; Published Online First: 31
October 2022
https://heart.bmj.com/content/early/2022/10/31/heartjnl-2022-321114.long
Grewal K, Atzema CL, Austin PC et
al. Intracranial hemorrhage after head injury among older patients on
anticoagulation seen in the emergency department: a population-based cohort
study. CMAJ 2021; 193(40): E1561-E1567
https://www.cmaj.ca/content/193/40/E1561.long
Kim D, Yang PS, Sung JH, et al. Effectiveness and Safety of
Anticoagulation Therapy in Frail Patients With Atrial
Fibrillation. Stroke 2022; 53(6): 1873-1882
https://www.ahajournals.org/doi/10.1161/STROKEAHA.121.036757
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