Outcomes of anticoagulation therapy in patients with mental health conditions

Background: Patients with mental health conditions (MHCs) experience poor anticoagulation control when using warfarin, but we have limited knowledge of the association between specific mental illness and warfarin treatment outcomes. Objective: To examine the relationship between the severity of MHCs and outcomes of anticoagulation therapy. Design: Retrospective cohort analysis. Participants: We studied 103,897 patients on warfarin for 6 or more months cared for by the Veterans Health Administration during fiscal years 2007-2008. We identified 28,216 patients with MHCs using ICD-9 codes: anxiety disorders, bipolar disorder, depression, post-traumatic stress disorder, schizophrenia, and other psychotic disorders. Main Measures: Outcomes included anticoagulation control, as measured by percent time in the therapeutic range (TTR), as well as major hemorrhage. Predictors included different categories of MHC, Global Assessment of Functioning (GAF) scores, and psychiatric hospitalizations. Key Results: Patients with bipolar disorder, depression, and other psychotic disorders experienced TTR decreases of 2.63 %, 2.26 %, and 2.92 %, respectively (p < 0.001), after controlling for covariates. Patients with psychotic disorders other than schizophrenia experienced increased hemorrhage after controlling for covariates [hazard ratio (HR) 1.24, p = 0.03]. Having any MHC was associated with a slightly increased hazard for hemorrhage (HR 1.19, p < 0.001) after controlling for covariates. Conclusion: Patients with specific MHCs (bipolar disorder, depression, and other psychotic disorders) experienced slightly worse anticoagulation control. Patients with any MHC had a slightly increased hazard for major hemorrhage, but the magnitude of this difference is unlikely to be clinically significant. Overall, our results suggest that appropriately selected patients with MHCs can safely receive therapy with warfarin.