Introduction: anticoagulants and anti-platelet drugs have been shown in ran
domized trials to reduce the risk of stroke in patients with atrial fibrill
ation (AF). We therefore investigated their use in patients known to be in
AF before a stroke, transient ischaemic attack (either cerebral or ocular)
or retinal artery occlusion to assess the influence of trials on clinical p
ractice.
Methods: inpatients and outpatients with acute stroke, transient ischaemic
attack or retinal artery occlusion were prospectively identified by a strok
e physician from 1990 to 1997. The presence or absence of AF before the vas
cular event, and prior use of anticoagulant and anti-platelet drugs were re
corded at the time of the assessment and verified using information from ge
neral practitioner and hospital case notes.
Results: of 1934 patients with stroke or retinal artery occlusion, 191 (10%
) were in AF before their ischaemic event. Anticoagulants had been used in
40 (21%) of these, but only in 32 (2%) of the 1743 patients in sinus rhythm
[odds ratio (OR) 14.2, 95% confidence interval (CI) 8.6-23.2]. Anti-platel
et drugs had been used in 62 (32%) of those with AF compared with 500 (30%)
of those in sinus rhythm (OR 1.2, 95% CI 0.9-1.64). Of the 161 patients in
AF without contraindications to anticoagulants, only 36 (22%) were taking
them. Although there was a statistically significant increase in anticoagul
ant use from 8% in 1990 to 23% in 1996, this could be explained solely by a
fall in the age of the patients referred to our hospital.
Conclusion: anticoagulation is probably under-used in AE We found no conclu
sive evidence that anticoagulation trials have influenced clinical practice
. This raises issues about the dissemination and implementation of trial re
sults.