Outcomes of Individualized Pharmaceutical Care in Atrial Fibrillation Patients at Warfarin Clinic, Klongluang Hospital, Pathumthani Province

Abstract

Objective: To evaluate the effects of individualized pharmaceutical care on knowledge, correctness of medication use, clinical outcomes, and the safety of warfarin use in patients with atrial fibrillation (AF). Methods: This quasi-experimental, one-group pretest-posttest study was conducted in 71 AF patients receiving warfarin from the Warfarin Clinic, Klongluang Hospital, who had out-of-range INR values and drug-related problems (DRPs). The study evaluated the following outcomes before and after pharmaceutical care intervention: 1) knowledge on warfarin use, using an 18-item questionnaire adapted from the Queen Sirikit Heart Center of the Northeast; 2) correctness of medication use, assessed by interviewing the patient or main caregiver; 3) INR values; 4) drug interactions; and 5) adverse events.  Results: The patients' mean knowledge score significantly increased from 13.4 ± 3.2 to 15.8 ± 2.1 (out of 18) (P<0.001). The percentage of patients who took their medication correctly increased from 80.28% to 98.59% (P<0.001). The proportion of patients with an INR in the target range (2.0–3.0) increased from 0% to 54.93% (P<0.001). Patients using drugs or food that could potentially interact with warfarin decreased from 42.25% to 7.04% (P<0.001). Warfarin-food and warfarin-other drug interactions decreased significantly (P=0.001 and P=0.003, respectively). The incidence of bleeding events decreased from 7.04% to 1.40%, although this was not statistically significant (P=0.134). Conclusion: Case-based pharmaceutical care may enhance therapeutic outcomes in patients with atrial fibrillation (AF) receiving warfarin by improving patient knowledge and adherence, maintaining INR within the therapeutic range, and reducing the incidence of interactions between warfarin and other drugs or food.