Table 2.

Clinician, patient and system determinants of overuse and underuse.

REASON FOR OVERUSE [REFERENCE #]		REASON FOR UNDERUSE [REFERENCE #]
P	Low-risk patients with genuine indication for anticoagulants for other non-AF conditions [40]	C	Fear of patient bleeding complication; overestimation of risk over benefits [20,22,24,32,36]
P	Low-risk patient preference to minimize risk of stroke [23]	C	CHA2DS2-VASc risk scores not documented or incorrect [23]
		C	Clinician lack of knowledge of the disease [27] Clinician’s lack of awareness of stroke risk from non-use of the combined CHA2DS2-VASc score and bleeding (HAS-BLED) score [22]
S	Update in guidelines in some countries no longer recommending antiplatelet agents in AF make others appear overprescribing [20,33]	C	GP perceived risk of bleeding if history of peptic ulcer or tumour [40]
S	Absence of a national guideline [20]	C	Doctor perceived lower thromboembolic risk in women than in men [20,40]
S	Evolution in risk prediction and wide availability of direct OA [24]	C	Older age a barrier to start OA [25,32] due to clinician’s perceived risk of bleeding [20,40]
S	Patient comorbidities, lack of social support or insurance status as incentive for in-hospital management [26]	C	Falls risk reduces clinician inclination to prescribe [20,23,40]
S	Aggressive promotion by pharmaceutical companies [20]	C	Lower inclination to prescribe in dementia, frailty syndrome [25], known poor patient compliance [40]
S	Lack of registry information on discontinuation at subsequent time points [33]	P	Patients’ unwillingness to receive prescription and non-adherence after prescription [24,33]
C	Low clinician familiarity with or adoption of risk stratification methods [20,26] or guidelines [24,27]	P	Documented contraindication: scheduled surgical procedure, active bleeding, reduce glomerular filtration, alcoholism [23,25,32,36]

AF = atrial fibrillation; OA = oral anticoagulants; C = clinician reason, P = patient reason; S = system determinant.