Evaluation of Warfarin Use in Patients With Mental Health Conditions in a Rural Community Health Center System

Background: Mental health conditions (MHCs) may affect a patient's ability to comply with requirements necessary for safe warfarin use. Objective: To describe warfarin control, defined as time in therapeutic range (TTR), for patients with and without MHCs receiving care through a pharmacist-driven anticoagulation service within a rural community health center system. Methods: Retrospective cohort study of patients on warfarin between January 1, 2014, and December 31, 2017. The primary study endpoint was TTR. Secondary endpoints were the number of international normalized ratios (INRs) per 30 days, percentage of INRs within, above, and below target range, and warfarin-related adverse events. Results: A total of 79 patients were included-37 with and 42 without MHCs. Patients were mostly male (n = 47; 59.5%) and prescribed warfarin for atrial fibrillation (n = 45; 57.0%). There were no differences in overall TTR between those with (59.6%; interquartile range = 41.8-73.4) versus without (63.4%; interquartile range = 46.7-73.6) MHCs (P = .542). Secondary outcomes showed no differences in the frequency or percentage of INRs in, above, or below target range (all P > .05). However, there were about twice as many hemorrhagic complications in the group with MHCs (27% vs 11.9%; P = .149). Conclusion: Patients with MHCs experienced no difference in overall TTR as compared to patients without MHCs. However, there was a non-statistically significant reduction in TTR, which would be consistent with limited existing data and demonstrates possible reproducibility to a rural, underserved patient population. Future research is needed to validate these outcomes.