Warfarin: implementing its safe use in hospitalized patients from nursing homes and community through a performance improvement initiative.

Introduction: Warfarin is increasingly used to prevent thromboembolism but adverse drug events (ADEs) are common. The National Safety Goals (3E) 2008 recommend that institutions develop processes to monitor the safe use of warfarin. Despite these guidelines, adverse events (bleeding) are common. This initiative, in an academic hospital, tracked warfarin use before and after using a PI process aimed at improving safe use of warfarin in hospitalized adults.

Methods: Retrospective (PRE-initiative, September-December 2007) and prospective (POST-initiative, January-December 2008) data were collected on in-hospital and prior warfarin use, demographics, medical history, initial and in-hospital warfarin maintenance dosing, hematocrit, International Normalized Ratio (INR), hepatic and renal function and adverse events related to warfarin use. Education on the appropriate use of warfarin was provided through formal and informal sessions and during daily hand-off sessions.

Results: A total of 308 patients receiving oral warfarin were examined (mean age 70 ± 17(SD) years, 47% males, 36% from nursing homes). Age, sex ratios, and place of residence were similar PRE- versus POST-initiative. Overall initial and maintenance warfarin doses were significantly lower POST-initiative (P = .0129 and P = .0319, respectively) and these decreases occurred exclusively in patients with supratherapeutic INR levels (>3.0). During the POST-period, the prevalence of high INR levels and bleeding events during hospitalization also decreased significantly (P = .015 and P < .0005, respectively). Finally, concomitant use of anticoagulant and/or antiplatelet drugs was significantly decreased POST-initiative (P = .028).

Conclusions: Most hospitalized patients (PRE- and POST-) presented with INRs in the sub- or supratherapeutic ranges (<2 and >3, respectively), requiring warfarin dose adjustments. Education through this initiative resulted in significantly lower average maintenance doses of warfarin, less use of concomitant anticoagulant or antiplatelet drugs, fewer supratherapeutic range INRs, and fewer adverse events during warfarin therapy. Education through a PI initiative is a simple and effective means to implement safer use of warfarin in the in-hospital setting.