Evaluation of dabigatran prescribing practices at University of Illinois Medical Center

Purpose: Dabigatran (D) is the first oral anticoagulant available as an alternative to warfarin in 58 years. It was approved in October 2010 with only one indication; the prevention of stroke or systemic thromboembolism for nonvalvular atrial fibrillation. Unlike warfarin, dosing is a fixed bid regimen based on renal function and does not require INR monitoring.  The University of Illinois Medical Center (UIMC) clinical pharmacists proactively educated physicians, nurses, and pharmacists on proper use of D.  Additional education was provided as new information became available, specifically reports of bleeding and an update to the package insert. The objective of this study is to evaluate the prescribing practices since regulatory approval of D at UIMC.

Methods: Retrospective review of D prescriptions from 12/10/10-12/23/11. Demographics, past medical history, CrCl, concomitant anti-platelet therapy and PGP-inhibitors were evaluated. High risk for bleeding was defined as age >75, CrCl ≤30mL/min, on concomitant PGP-inhibitors, and/or body weight <60 kg.

Results: Among the 92 D prescriptions, 60 were converted from warfarin and 32 were new to anticoagulation.  The mean age was 66.1 ± 13.4 years, 63.0% were male, 58% Caucasian, 31% African American, 11% other.  Forty-seven percent of patients were taking daily aspirin and 0 were on other anti-platelet therapy.  

Table 1: Prescribing Trend
	n(%)
Indication appropriate	92 (100.0)
CrCl>30mL/min and on 150mg BID (n=83)	77/83 (92.8)
CrCl ≤30mL/min and on 75mg BID (n=9)	9/9 (100.0)

Table 2: Bleeding Risk
	n(%)
Age > 75 years	25 (27.2)
CrCl ≤30mL/min	9 (9.8)
Body weight <60kg	4 (4.3)
PGP-inhibitors and CrCl>30mL/min (n=83)	11/83 (13.3)
PGP-inhibitors and CrCl ≤30mL/min	0 (0)

Conclusion: These data suggest that patients of UIMC are prescribed and dosed on D appropriately without significant drug interactions. Proactive education to prescribers may have contributed to appropriate prescribing. The most common bleeding risk is age > 75.