Screening Improves Detection Of Major Stroke Risk Factor

The prevalence of atrial fibrillation rises with age, from about 1% in the whole population to about 5% in people aged over 65. It can be diagnosed using a simple low cost test (electrocardiography) and the risk of serious problems, such as stroke, can be dramatically reduced by treatment.

There are two types of screening for atrial fibrillation -- opportunistic and systematic (or total population) screening. In opportunistic screening, a healthcare professional would take a patient's pulse during a consultation and, if the pulse was irregular, electrocardiography would be performed to confirm the diagnosis. In systematic screening, the whole target population would be invited for screening by electrocardiography.

So researchers set out to test whether screening was more effective than routine care in detecting atrial fibrillation in the community, and compared opportunistic with total population screening.

They identified 14,802 patients aged 65 or over from 50 general practices in England (split into 25 intervention and 25 control practices).

Patients in intervention practices were randomly allocated to systematic screening (invitation for electrocardiography) or opportunistic screening (pulse taking and electrocardiography if the pulse was irregular). Screening took place over 12 months in each practice from October 2001 to February 2003. No active screening took place in control practices.

Screening practices identified substantially more cases of atrial fibrillation than control practices. Systematic and opportunistic screening detected similar numbers of new cases.

The screening processes, whether systematic or opportunistic, did not raise anxiety and were acceptable to patients.

This finding suggests that routine electrocardiography within this population is unnecessary for the detection of atrial fibrillation as long as healthcare professionals are conscientious about feeling the pulse, say the authors.

As the detection rates were essentially identical for the two methods, the more labour intensive, costly, and intrusive approach with systematic screening cannot be justified, they conclude.