ANTICOAGULATION: GUIDELINES AND CONSULTATION REDUCES BLEEDS AND VENOUS THROMBOEMBOLISM

Landefeld et al.. Ann Intern Med. 1992 May 15;116;829-37 Expires May 2000

The study: unblinded randomised controlled trial with intention to treat
Setting: university teaching hospital, Canada
101 patients (mean age 72; 55% women) treated with warfarin or heparin, and judged to at moderate (n = 60) or high risk (n = 41) for bleeding

Excluded if

• anticoagulant treatment within 30 days of admission
• treatment for < 10 days

Control group (n = 55; 55 analysed): usual care: nursing and medical care from housestaff supervised by an attending physician.
Experimental group (n = 46; 46 analysed) usual care plus consultation: guideline-based consultative care with daily visits by a study physician using specific practice guidelines.
Guidelines used based on recommendations made by the ACCP consensus conferences (1986, 1989, 1992). Used for assessing risks and benefits of therapy; alternative treatment; formulation and discussion of specific recommendations for the use, dose, and duration of anticoagulants; and daily follow-up.

100% followed for 3 months.

Outcomes:

1. Major bleeding : overt bleeding that led to loss of ³ 2 units of blood in < 7 days.
2. Minor bleeding: other internal bleeding, a drop of ³ 0.06 in hematocrit that led to transfusion of ³ 2 units of blood, or a drop of 20% in hematocrit to < 0.30 at discharge.

The evidence:

outcome	time to outcome	CER	EER	RRR (95% CI)	ARR (95% CI)	NNT (95% CI)
minor or major bleeding	3 months	17 (30.9%)	6 (13.0%)	58% (2% to 82%)	17.9% (2.24% to 33.5%)	6 (3 to 45)
major bleeding	3 months	7 (12.7%)	2 (4.35%)	66% (-57% to 93%)	8.35% (-2.24% to 18.94%)	12 (NNT = 5 to inf; NNH = 45 to inf)
new or recurrent PE or DVT	3 months	9 (16.4%)	2 (4.35%)	73% (-17% to 94%)	12.1% (0.63% to 23.48%)	8 (4 to 160)
death	3 months	6 (10.9%)	6 (13.0%)	-20% (-246% to 59%)	-2.14% (-14.9% to 10.6%)	-47 (NNT = 9 to inf; NNH = 7 to inf)

Comments:

1. Potentially reversible factors associated with bleeding
• prothrombin time > 2 times control
• activated partial thromboplastin time > 3 times baseline
• insufficient indication for anticoagulation
• use of nonsteroidal anti-inflammatory agents
• failure to use alternative therapy e.g. vena cava filter

Citation:
Consultation and Guidelines to Reduce Anticoagulant-related Bleeding ACP Journal Club. 1992 Sept-Oct;117:61 summary of Landefeld CS, Anderson PA. Guideline-based consultation to prevent anticoagulant-related bleeding. A randomized, controlled trial in a teaching hospital. Ann Intern Med. 1992 May 15;116;829-37.

Appraiser: CMBall (cmball11@aol.com) on July, 14, 1998

Search terms: warfarin in Best Evidence

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