Comparison of two different models of anticoagulation management services with usual medical care

To evaluate the safety and economic impact of three models of anticoagulation management services: usual medical care, a nurse-managed service, and a pharmacist-managed service.

Retrospective medical record review.

An eight-county health care system in central New York State.

Nine hundred ninety-six patients (age range 19-99 yrs) who were receiving warfarin therapy for at least 6 months and who had three or more international normalized ratio (INR) values reported during the 1-year study period; 489 patients (6243 INR values) were in the pharmacist-managed group, 307 patients (3618 INR values) were in the nurse-managed group, and 200 patients (3142 INR values) were in the usual care group.

All INR measurements were performed by the central laboratory or by on-site point-of-care testing. Data were queried from calendar year 2003 for the usual care and nurse-managed services and calendar year 2006 for the pharmacist-managed service. Anticoagulation indication, INR goal, baseline characteristics, and rates and costs of hospitalization and emergency department visits directly related to anticoagulation therapy were extracted from the medical record. If the INR goal was not documented, a range was assigned as appropriate from the American College of Chest Physicians anticoagulation guidelines. Markers of anticoagulation control--time in range (percentage of time a patient is maintained within their therapeutic range) and percentage of INR values in range--were calculated for each study group. Baseline characteristics were similar among all study groups. The pharmacist-managed service yielded the lowest rates of hospitalization and emergency department visits, with hospitalizations reduced by 56% versus nurse-managed service and 61% versus usual care (p<0.01). Emergency department visits were reduced by 78% in both the nurse-managed and usual care models (p<0.002). Based on visit rates, the pharmacist-managed service averted $141,277.34 in hospitalization costs and $10,183.76 in emergency department visit costs versus the nurse-managed service and $95,579.08 in hospitalization costs and $5511.21 in emergency department costs compared with the usual care model.

Pharmacist-managed anticoagulation management services reduced the rates of anticoagulation-related emergency department visits and hospitalizations, with significant financial impact. Based on results of this study, a collaborative clinic using pharmacists, nurses, and physicians may be the optimal structure for an anticoagulation management service, with these results verified in future prospective randomized studies.