Optimization of inpatient warfarin therapy: Impact of daily consultation by a pharmacist-managed anticoagulation service

OBJECTIVE: TO determine the effect of daily consultation by a team or hospi tal pharmacists on the accuracy and rapidity of optimizing warfarin therapy , DESIGN: Comparison of a historical control cohort with a prospective coho rt matched for treatment indication. SETTING: A 400-bed university teaching hospital. PATIENTS: Sixty consecutive patients hospitalized in 1992 and starting warf arin for the first time, with anticoagulation therapy anticoagulation ther, were compared with 60 patients matched for warfarin indication. hospitaliz ed in 1995, but with anticoagulation therapy managed with pharmacy consulta tion. RESULTS: Pharmacist management of initial warfarin therapy resulted in a si gnificant reduction in the length of hospitalization compared with physicia n dosing, from 9.5 +/- 5.6 days to 6.8 +/- 4.4 days (p = 0.909). The number of patients and patient-bays with international normalized ratio (INR) val ues >3.5 were reduced by pharmacist dosing from 37 patients and 142 days to 16 patients and 29 days, respectively (p < 0.001). Similarly, the number o f patients and patient-days with INR >6.0 were reduced from 20 patients and 50 days to two patients and six days, respectively (p < 0.001). There were six documented bleeding complications in compared with one in 1995 (p = 0. 11). The mean INR at discharge was significantly lower in the pharmacy surv eillance group, 2.6 +/- 0.58, compared with the physician cohort, 3.3 +/- 2 .1 (p = 0.07). Readmissions after discharge due to bleeding or recurrent th rombosis were reduced from five (at 1 mo) and 10 (Bt 3 mo) to two and five readmissions, respectively, by pharmacist intervention (p = 0.43). The numb er of patients with concurrently prescribed digs known to significantly int eract with warfarin was significantly lower (6 vs. 13; p = 0.02) in the pha rmacy surveillance group. CONCLUSIONS: Among patients starting warfarin for the first time, daily con sultation by a pharmacist significantly decreased the length of hospital st ay and the number of patients who received excessive anticoagulation therap y, These findings translate into improved quality of care and potentially s ignificant cost savings.