Effects of Depressive and Other Psychiatric Disorders on Anticoagulation Control in a Pharmacist-Managed Anticoagulation Clinic

Background: The impact of psychiatric disorders on International Normalized Ratio (INR) control and adverse events for patients receiving warfarin has not been fully elucidated. Objective: To determine the effect of depressive and other psychiatric disorders on anticoagulation control in a pharmacist-managed anticoagulation clinic. Methods: A retrospective chart review evaluated outcomes of patients with no history of psychiatric disorders and compare it with that of patients with either a history of depression or any form of psychiatric disorder. Data was obtained from patient medical records over a 24-month period. The primary outcome was a comparison of time in therapeutic range, calculated using 3 separate methods (percentage of INRs in therapeutic range, a modified Rosendaal’s linear interpolation, and mean INR in goal). Results: A total of 151 patients met the inclusion criteria (control = 79, psychiatric disorders = 72 patients). Control patients had a significantly greater proportion of INRs in the goal range compared with either the depression or psychiatric disorders groups (control, 55.7%; depression, 43.5%; psychiatric, 45.8%). Utilizing the Rosendaal’s method, patients with psychiatric disorders were in the goal range significantly less often than those in the control group (53.0% vs 61.3%). No differences were seen when adjusting for multiple comparisons or when comparing the control and depression groups (54.5% vs 61.3%). There was no difference between the groups when comparing percentages of patients with a mean INR in their goal range. Conclusions: Patients with psychiatric disorders who take warfarin may spend less time in the therapeutic range.