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.