Health care expenditures and therapeutic outcomes of a pharmacist-managed anticoagulation service versus usual medical care.

Study Objective: To evaluate the differences in health care expenditures and therapeutic outcomes of patients receiving warfarin therapy management by a pharmacist-managed anticoagulation service compared with those receiving warfarin management by usual medical care.

Design: Retrospective, matched-cohort study.

Data Source: University of Pittsburgh Medical Center (UPMC) and UPMC Health Plan.

Patients: Three hundred fifty adults who received warfarin therapy; 175 were managed by the pharmacist-managed anticoagulation service for at least 2 months between October 1, 2007, and September 30, 2008, (case patients) and 175 received usual care (matched comparison group).

Measurements And Main Results: Medical claims data compared were direct anticoagulation cost and overall medical care costs, anticoagulation-related adverse events, hospitalizations and emergency department visits, frequency of international normalized ratio (INR) testing, and quantity of warfarin refills. Operational costs of the anticoagulation service were also calculated. The INR values and time within therapeutic range were assessed through anticoagulation service reports and laboratory results. The direct anticoagulation care cost was $35,465 versus $111,586 and the overall medical care cost was $754,191 versus $1,480,661 for the anticoagulation service group versus the usual care group. Accounting for operational and drug expenditure costs, the cost savings was $647,024 for the anticoagulation service group. The anticoagulation service group had significantly fewer anticoagulation-related adverse events (14 vs 41, p<0.0001), hospital admissions (3 vs 14, p<0.00001), and emergency department visits (58 vs 134, p<0.00001). The percentage of INR values in range and the percentage of time the INR values were in range were significantly higher in the anticoagulation service group (67.2% vs 54.6%, p<0.0001, and 73.7% vs 61.3%, p<0.0001, respectively). Compared with the usual care group, the anticoagulation service group had significantly more INR tests performed but demonstrated no significant difference in the quantity of drug refills.

Conclusion: After accounting for operational costs, pharmacist-managed anticoagulation leads to reduced health care expenditure while improving therapeutic outcomes compared with usual medical care.