Impact of an inpatient anticoagulation management service on clinical outcomes

BACKGROUND: Antithrombotic medications require careful management to avoid thrombotic or hemorrhagic complications. The benefits of specialized anticoagulation management services (AMS) in the outpatient setting are well established; less evidence of benefit in the hospital setting is available. OBJECTIVE: To evaluate the clinical benefits of an inpatient AMS to cardiac surgery patients requiring warfarin anticoagulation therapy. METHODS: After obtaining institutional review board approval, we conducted a retrospective, single-center, cohort study of consecutive cardiac surgery patients treated before (January 2003-May 2005) and after (June-December 2005) establishment of an inpatient AMS. Demographic and clinical characteristics as well as laboratory and clinical data were retrieved from institutional electronic databases and compared between the 2 patient cohorts. Comparisons between study groups were conducted using a χ² or Fisher's Exact test for categorical variables and a Student's t-test for continuous variables. Analysis of rare event data was conducted using Poisson regression analysis. RESULTS: Of 1919 patients admitted during the study interval, 826 received warfarin (674 pre-AMS, 152 post-AMS). The number of patients with postsurgical panic international normalized ratio (INR) values declined after initiation of the AMS (pre-AMS 90/674 [13.4%] vs post-AMS 11/152 [7.2%]; p = 0.036). There was a trend toward fewer clinically significant postoperative bleeding events (pre-AMS 21/674 [3.1%] vs post-AMS 2/152 [1.3%]; p = 0.22) and fewer repeat surgeries for late postoperative bleeding (pre-AMS 8/674 [1.2%] vs post-AMS 0/152 [0%]; p = 0.08). AMS intervention was associated with a 17% decrease in the average postsurgical length of stay (13.9 days vs 11.6 days; p = 0.015). CONCLUSIONS: A multidisciplinary AMS can improve anticoagulation management, leading to fewer panic INR values and a reduced length of hospital stay.