One-third of NOAC patients treated inappropriately: Study

Medicines

28 Apr 2016

One in three patients prescribed apixaban, dabigatran or rivaroxaban are not being treated according to evidence-based guidelines, a Brisbane study has found.

Published in the Internal Medicine Journal the study concluded that 55 of 174 patients studied were treated inappropriately.

Treatment with a NOAC was contraindicated in 40% of this group, mainly because of severe renal impairment (creatinine clearance <30 mL/min).

Another 22% were prescribed an excessively high dose, and 38% were under-dosed.

“Our findings imply that there remains considerable uncertainty about appropriate prescribing and dosing of NOACs, particularly in patients with impaired renal function,” the research team concluded.

“We recommend judicious prescribing and regular monitoring of renal function in patients at high risk of complications from NOAC therapy.”

NOAC users were identified in the records of patients admitted to Brisbane’s three major teaching hospitals during a three-month period in 2014.

Three-quarters were prescribed NOACs because of non-valvular atrial fibrillation, and the remainder because of a history of venous thromboembolism.

The majority had commenced treatment in the community. Their renal function was generally poorer than those initiated in hospital, but the appropriateness of prescribing was no different between the groups.

However, appropriate prescribing was higher in patients with VTE rather than AF (85% vs 60%).

“A limited number of elderly patients (75 years of ager and older), or those with significant renal impairment or at extremes of body weight, were included in the major landmark clinical trials,” Ms Pattullo said.

In addition, patient selection and the frequency of review in routine clinical practice may not match the standards achieved in trials.

“If an incorrect dose is selected, a patient’s physiological parameters change, or interacting concomitant medications are erroneously assed, patients may receive inappropriate NOAC therapy for long periods of time without review or monitoring.

“These concerns have been borne out by reports of increased bleeding associated with NOAC use in the elderly.”

The research team recommended continued promotion of current guidelines on NOAC use, as well as routine monitoring of renal function during treatment.

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