A retrospective evaluation of the management of excessive anticoagulation in an established clinical pharmacy anticoagulation service compared to traditional care.

BACKGROUND

Analysis of the outcomes associated with episodes of excessive anticoagulation (international normalized ratio [INR] > 6.0) managed by physicians in a group model health maintenance organization (HMO) revealed opportunities for improvement. A centralized, telephone follow-up Clinical Pharmacy Anticoagulation Service (CPAS) was later implemented in the same HMO. We sought to compare the outcomes of excessive anticoagulation episodes managed by CPAS pharmacists to traditional physician management.

METHODS

Computerized laboratory information was used to identify episodes of excessive anticoagulation managed by CPAS clinical pharmacists during the 6-month study. Pertinent data were collected through retrospective medical record review. Results were compared to a similar analysis conducted prior to CPAS implementation (traditional management).

RESULTS

A total of 313 INR episodes >6.0 were identified in the CPAS group compared to 301 in the traditional management group. 6.3% of patients in the traditional management group experienced major bleeding compared to 1.3% in the CPAS group (p = 0.001). The majority of excessive anticoagulation episodes in both groups were managed by temporarily withholding warfarin therapy. Phytonadione was administered more frequently in the traditional management group than the CPAS group, 17.0% vs. 6.4%, respectively (p < 0.001). Traditional management patients also received higher doses of phytonadione than CPAS patients, 13.0 mg vs. 3.3 mg, respectively (p < 0.001). Aggressive use of phytonadione in the traditional management group resulted in two episodes of iatrogenic thromboembolism while no such episodes occurred in the CPAS group.

CONCLUSIONS

The management of excessive anticoagulation by a centralized telephone follow-up anticoagulation service staffed by clinical pharmacists resulted in improved clinical outcomes compared to traditional management.