Medication therapy problems detected at community pharmacy INR checks

Despite the shift towards direct-acting anticoagulants, warfarin remains widely used in Canada and is traditionally managed by family physicians through laboratory-based international normalized ratio (INR) testing. The Community Pharmacy Anticoagulation Management Service (CPAMS) in Nova Scotia represents an innovative approach, enabling community pharmacists to conduct point-of-care (POC) INR testing and manage warfarin therapy. A potential benefit of this approach is the opportunity to identify non-warfarin medication therapy problems (nwMTPs) during routine visits.

We conducted a prospective, multicentre, observational study across 40 community pharmacies in Nova Scotia, part of CPAMS's second phase. Pharmacists documented nwMTPs identified in patients with atrial fibrillation during routine POC INR visits using the Qualtrics Insight Platform, categorizing them by indication, effectiveness, safety, or adherence, alongside corresponding interventions.

Over 6 months, 43 nwMTPs were submitted from 13 unique pharmacies. There were 3404 POC INR tests in patients with atrial fibrillation, yielding an estimated nwMTP detection rate of 1.26 (95% CI, 0.69 to 2.32) per 100 INR tests. The most common nwMTP category was "Indication," primarily requiring additional therapy. Pharmacists frequently intervened by recommending medication adjustments or providing patient education.

The findings highlight a modest, yet potentially significant role of pharmacists in detecting and managing diverse MTPs during focused warfarin management assessments. The predominance of indication-related problems underscores unmet therapeutic needs in patients on warfarin.

This study illustrates the potential of pharmacist-led POC INR testing in community settings to identify and address nwMTPs, contributing to comprehensive patient care.