Managing Warfarin Drug Interactions: The Bayview Experience

1. Managing Warfarin Drug Interactions: The Bayview Experience Charles H. Twilley, MBA, PharmD Johns Hopkins Bayview Medical Center Baltimore, MD USA DAWN Users Group, November 2002

2. Where is Maryland? USA The capital of the state

3. Where is Baltimore? Salisbury is REALLY the cultural epicenter of the state!

4. Where in Baltimore is Bayview?

5. Bayview Overview • Community Teaching Hospital • Member Institution of Johns Hopkins Healthcare • 692 beds • 320 acute care • 255 long term/geriatric • 117 rehabilitation/transitional care

6. The Anticoagulation Service At Bayview • Clinical Initiative of the Department of Pharmacy Services • Occupies 1 FTE • Responsible for all aspects of chronic anticoagulation management, including acute bridge therapy with heparin, outpatient DVT Tx. • Currently has 625 patients on service; up from 285 in 1998

7. JHBMC Patient Breakdown by Diagnosis

8. PATIENT VOLUME

9. Problems with Anticoagulation Management at Bayview • No formalized inpatient management service • approval slated for November, 2002 • Difference in level of pharmaceutical care between acute and long term care • JHBMC is a teaching facility • Large geriatric population

10. Magnitude of the Problem • Warfarin associated 22% of adverse drug reactions in Q3 FY 2000-2001 • Heparin is associated with 51% of medication errors for Q1-Q3 FY 2000-2001 • Problems with anticoagulation management implicated in two sentinel events over the past 16 months • Adverse Drug Events (ADE’s) are associated with cost of $7000 per event (1997 study finding)

11. Case Study • CJ: 48 y.o. AA male, s/p cadaveric renal transplant, developed embolic CVA • chronically anticoagulated for 4 years • Presented to PCP with painful, discolored, cracking of great toe; diagnosed as onychomycosis • Treated with itraconazole 100mg po qd

12. Case Study: 14 days later • Presents to AC clinic • Pertinent findings • INR 18.5 (repeated and verified) • Hgb/Hct: 7.5/22 • Guiac: + • When asked why • neither my doctor nor the pharmacist that filled the prescription thought it would be a problem

13. The final outcome • Three day admission • 4 units PRBC’s transfused • Cost to the health care system of $5000-7000 • ? Cost in lost productivity, work time, etc. • Could this have been avoided?

14. What could the ACS do? • Prevent admissions from outpatients served • Instill the notion of drug interactions into introductory didactic patient education • Implement specific, evidence-based policies and procedures to address management • Utilize management database to facilitate

15. How did the ACS utilize DAWN AC? • Utilized the drug interactions screen function • incorporated Drug Interaction algorithm into interaction tracking function • provided prescriber with notification of interaction and cited literature

16. How did we test our results? • Identified drug interactions with clinically relevant evidence of severity • chose drug with Evidence Levels I and II of clinical significance (Wells, et al.) • Evaluated efficacy of our ACS to prevent/minimize warfarin interactions • Conducted prospective evaluation from 07/01/99 to 01/01/2000 to evaluate efficacy

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21. Results

22. Clinical Adverse Outcomes

23. Conclusions • Potential interactions with warfarin occur at a rate of 23.5 events/100 patient years • A defined algorithmic approach can minimize the incidence of supratherapeutic INR’s, thus minimizing adverse clinical events. • Provider notification and intervention within 72 hours after a potentially interacting medication is started may reduce the risk of major bleeding. Patients need to be continually reminded to inform their anticoagulation care provider when new medications are initiated.

24. Added Benefits • Problem: • JHBMC was showing $6M in laboratory fees not retrieved • Solution: • modify DAWN AC database to create link between patient demographics

25. Net Result • Created a centralized database for billing department • Created a template for other clinical services • Able to retrieve $1.8M of $6M deficit

26. What else? • Induction regimen function to facilitate ambulatory DVT treatment • Report writing capabilities • Database management/query abilities • Screens for monitoring/preventing adverse drug outcomes

27. The Bayview Experience • Facilitated expansion from 285 to 625 patients • Facilitated ability to capture workflow fluctuations • Facilitated ability to capture clinical interventions

28. Future Initiatives • Use of induction module to undertake inpatient ACS • use of hand held technology to make ACS a “mobile” clinical entity • further expand outpatient clinical pharmacy services • Lipid management, diabetes management

29. Questions, comments, concerns? E-mail: ctwilley@jhmi.edu