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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






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



Wajngarten M. Oral Anticoagulant Mistakes to Avoid in Older Adults With AF. Medscape Medical News 2022; December 23, 2022



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



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



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






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