Primary prevention of arterial thromboembolism in non-rheumatic atrial fibrillation in primary care: randomised controlled trial comparing two intensities of coumarin with aspirin.
OBJECTIVE
To investigate the effectiveness of aspirin and coumarin in preventing thromboembolism in patients with non-rheumatic atrial fibrillation in general practice.


METHODS
Randomised controlled trial.


METHODS
729 patients aged >/=60 years with atrial fibrillation, recruited in general practice, who had no established indication for coumarin. Mean age was 75 years and mean follow up 2. 7 years.


METHODS
Primary care in the Netherlands.


METHODS
Patients eligible for standard intensity coumarin (international normalised ratio 2.5-3.5) were randomly assigned to standard anticoagulation, very low intensity coumarin (international normalised ratio 1.1-1.6), or aspirin (150 mg/day) (stratum 1). Patients ineligible for standard anticoagulation were randomly assigned to low anticoagulation or aspirin (stratum 2).


METHODS
Stroke, systemic embolism, major haemorrhage, and vascular death.


RESULTS
108 primary events occurred (annual event rate 5.5%), including 13 major haemorrhages (0.7% a year). The hazard ratio was 0.91 (0.61 to 1.36) for low anticoagulation versus aspirin and 0.78 (0.34 to 1.81) for standard anticoagulation versus aspirin. Non-vascular death was less common in the low anticoagulation group than in the aspirin group (0.41, 0.20 to 0.82). There was no significant difference between the treatment groups in bleeding incidence. High systolic and low diastolic blood pressure and age were independent prognostic factors.


CONCLUSIONS
In a general practice population (without established indications for coumarin) neither low nor standard intensity anticoagulation is better than aspirin in preventing primary outcome events. Aspirin may therefore be the first choice in patients with atrial fibrillation in general practice.
Hellemons
B S
BS
Department of General Practice, University of Maastricht, 6200 MD Maastricht, Netherlands. Bep.Hellemons@HAG.Unimaas.NL
Langenberg
M
M
Lodder
J
J
Vermeer
F
F
Schouten
H J
HJ
Lemmens
T
T
van Ree
J W
JW
Knottnerus
J A
JA
D000368:Aged; D000925:Anticoagulants / Q000008:administration & dosage* / Q000009:adverse effects; D001241:Aspirin / Q000008:administration & dosage* / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000517:prevention & control*; D003374:Coumarins / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage* / Q000009:adverse effects; D016016:Proportional Hazards Models; D016019:Survival Analysis; D013923:Thromboembolism / Q000517:prevention & control*; D016896:Treatment Outcome
D000925:Anticoagulants; D003374:Coumarins; D010975:Platelet Aggregation Inhibitors; C030123:coumarin; D001241:Aspirin