In This Edition
Literature At A Glance
A guide to this month’s studies
- Warfarin vs. aspirin in heart-failure patients
- Aspirin after anticoagulation prevents VTE recurrence
- Novel oral anticoagulants vs. warfarin in afib patients
- Intravenous metronidazole for mild C. diff infection
- Frequency of Foley catheter complications vs. CAUTI
- Intensive hyperglycemia control in noncritical hospitalized patients
- Risk score predicts 30-day mortality after noncardiac surgery
- Temperature, white blood cell count are not sensitive predictors of bacteremia
Warfarin Reduces Stoke but Increases Hemorrhage Compared with Aspirin in Patients with Heart Failure and Sinus Rhythm
Clinical question: Is warfarin superior to aspirin with regard to clinical outcomes in patients with heart failure who are in sinus rhythm?
Background: Heart failure is associated with stroke and death potentially caused by atherothrombotic events. Anticoagulation is efficacious in some heart failure patients with atrial fibrillation or significant valvular disease, but the role of anticoagulation versus aspirin in patients with chronic heart failure and sinus rhythm is unclear.
Study design: Double-blind randomized controlled trial.
Setting: Multicenter, multinational trial involving outpatients.
Synopsis: This double-blind, double-dummy trial involving 2,305 patients with sinus rhythm and reduced left ventricular ejection fraction (<35%) showed no significant difference in the primary combined outcome (ischemic stroke, intracerebral hemorrhage, or death) in those treated with warfarin as compared with aspirin. Warfarin did significantly reduce the rate of ischemic stroke by 0.64 events per 100 patient-years (absolute risk reduction 2.2%, number needed to treat 45) when compared with aspirin, with no significant difference in the rate of intracerebral hemorrhage. This outcome was offset by an increased rate of major hemorrhage by 0.91 events per 100 patient-years (absolute risk increase 3.1%, number needed to harm 32).
This study included patients from all functional classes of heart failure, with a protocol to initiate treatment with other standard heart failure medications. Patients with an indication for either warfarin or aspirin were excluded. Due to recruitment difficulties, the power of this study was reduced. Other study limitations included a relatively low percentage of time that patients on warfarin were in therapeutic range and a substantial period of follow-up time in which patients did not receive the assigned study treatments.
Bottom line: The benefit of reduced stoke in patients with heart failure and sinus rhythm who take warfarin over aspirin is counteracted by an increased risk for serious bleeding outcomes.
Citation: Homma S, Thompson JLP, Pullicino PM, et al. Warfarin and aspirin in patients with heart failure and sinus rhythm. N Engl J Med. 2012;366(20):1859-1869.
Aspirin Use after Recommended Anticoagulation Treatment Prevents Recurrence in VTE Patients
Clinical question: Does aspirin prevent recurrence in patients after treatment with anticoagulation following their first episode of unprovoked VTE?
Background: VTE recurrence is common following the discontinuation of anticoagulation, particularly in patients with a history of unprovoked pulmonary embolism (PE) or DVT. Extension of treatment with vitamin K antagonists decreases recurrence but also causes more bleeding. The role of aspirin in the secondary prevention of VTE is unknown.
Study design: Double-blind randomized controlled trial.
Setting: Multicenter international trial involving outpatients.
Synopsis: This trial compared treatment with aspirin versus placebo for approximately two years in 205 patients with a history of unprovoked VTE who had completed six to 18 months of anticoagulant therapy. The relative risk reduction of recurrent VTE in the aspirin versus the placebo group was approximately 40% per year (6.6% vs. 11.2% per year; absolute risk reduction 4.6% per year; number needed to treat 22). No difference in major or clinically relevant bleeding was observed between the two groups.