Background: Anticoagulants including direct oral anticoagulants (DOACs) are among the highest-risk medications in the United States. We postulated that routine consultation and follow-up from a clinical pharmacist would reduce clinically important medication errors (CIMEs) among patients beginning or resuming a DOAC in the ambulatory care setting.

Objective: To evaluate the effectiveness of a multicomponent intervention for reducing CIMEs.

Design: Randomized controlled trial.

Participants: Ambulatory patients initiating a DOAC or resuming one after a complication.

Intervention: Pharmacist evaluation and monitoring based on the implementation of a recently published checklist. Key elements included evaluation of the appropriateness of DOAC, need for DOAC affordability assistance, three pharmacist-initiated telephone consultations, access to a DOAC hotline, documented hand-off to the patient's continuity provider, and monitoring of follow-up laboratory tests.

Control: Coupons and assistance to increase the affordability of DOACs.

Main measure: Anticoagulant-related CIMEs (Anticoagulant-CIMEs) and non-anticoagulant-related CIMEs over 90 days from DOAC initiation; CIMEs identified through masked assessment process including two physician adjudication of events presented by a pharmacist distinct from intervention pharmacist who reviewed participant electronic medical records and interview data.

Analysis: Incidence and incidence rate ratio (IRR) of CIMEs (intervention vs. control) using multivariable Poisson regression modeling.

Key results: A total of 561 patients (281 intervention and 280 control patients) contributed 479 anticoagulant-CIMEs including 31 preventable and ameliorable ADEs and 448 significant anticoagulant medication errors without subsequent documented ADEs (0.95 per 100 person-days). Failure to perform required blood tests and concurrent, inappropriate usage of a DOAC with aspirin or NSAIDs were the most common anticoagulant-related CIMEs despite pharmacist documentation systematically identifying these issues when present. There was no reduction in anticoagulant-related CIMEs among intervention patients (IRR 1.17; 95% CI 0.98-1.42) or non-anticoagulant-related CIMEs (IRR 1.05; 95% CI 0.80-1.37).

Conclusion: A multi-component intervention in which clinical pharmacists implemented an evidence-based DOAC Checklist did not reduce CIMEs.

Nih trial number: NCT04068727.