Audit of anticoagulant therapy and acute hospital admissions

Abstract

We conducted an audit on the contribution of failure of control of anticoagulant therapy to acute hospital admissions. Over a period of 3 months there were 1480 acute admissions. One-hundred-and-twelve (7.6%) of these patients were on anticoagulant therapy. One-hundred-and-three of these 112 patients were evaluated, 74 patients had international normalized ratios (INRs) in the therapeutic range, of whom four (5.4%) bled from causes unlikely to be due directly to anticoagulant therapy. Twenty-nine patients were over-anticoagulated. Of these, 17 (59%) were admitted with bleeding symptoms, which may have been a consequence of high INR, while one had a very high INR but no bleeding. Eleven more patients were admitted for reasons unrelated to anticoagulant therapy but were found to have over-therapeutic INRs, which may have influenced their subsequent hospital management. The only clear difference between the bleeding and nonbleeding groups was age. Reasons for over-anticoagulation were poor patient compliance in 31%, influence of other medications in 17, congestive heart failure in 28%, and unknown in 24%. In conclusion, 22/1480 hospital admissions (1.5%) were due to warfarin complications and 16/21 bleeding patients had INRs > 4.5. These are admissions that could potentially be avoided with better anticoagulation control.

Training Australian pharmacists for participation in a collaborative, home-based post-discharge warfarin management service

“…Although its therapeutic efficacy and the current absence of any viable oral alternatives have cemented warfarin's role in clinical practice, it is well recognised internationally as a high-risk drug for adverse drug events (ADEs) [3][4][5]. The initiation and stabilisation phase of warfarin therapy is a particularly high-risk period, with the risk of major bleeding in the first month of therapy approximately ten times the risk after the first year [6][7][8][9].…”

Spontaneous Intramural Small Bowel Hematoma Associated With Warfarin Nonadherence in an Elderly Patient

“…In a previous study, poor adherence of elderly patients was responsible for 31% of overanticoagulation cases 9 . These admissions could potentially be avoided with better anticoagulation control.…”

Drug-related problems identified in post-discharge medication reviews for patients taking warfarin

“…Warfarin is recognised as a high-risk drug [2,[7][8][9], with warfarin-related ADEs a significant cause of hospital admissions. In one study, warfarin complications were responsible for 1.5% of hospital admissions and the majority of these admissions were considered preventable [10]. An Australian study suggested that anticoagulants, including warfarin, were responsible for up to 9.0% of all ADEs resulting in or prolonging hospitalisation between 1981 and 2002 among older patients [11].…”