A Cochrane review[Abstract] 1 included one cluster randomised controlled trial involving 50 general practices in England with a total of 14 829 subjects aged 65 or over. Patients in intervention practices (n=9 866) were randomly allocated to systematic screening (invitation for electrocardiography) or opportunistic screening (pulse taken when they visited their general practitioner for any reason and invitation for electrocardiography if the pulse was irregular). No active screening took place in control practices (n=4 963). Both these screening programmes increased the rate of detection of new cases of atrial fibrillation compared to normal practice (Table T1). Both systematic and opportunistic screening were more effective in men (OR 2.68, 95% CI 1.51 to 4.76 and OR 2.33, 95% CI 1.29 to 4.19, respectively) than in women (OR 0.98, 95% CI 0.59 to 1.62 and OR 1.2, 95% CI 0.74 to 1.93, respectively). No data on the effectiveness of screening in different ethnic or socioeconomic groups were available.
| Outcome | Participants (studies) | Assumed - Routine practice* | Corresponding - Systematic screening* | Relative effect | Number needed to screen |
|---|---|---|---|---|---|
| Number of new diagnoses (follow up 12 months) | 9 075 (1 study) | 10 per 1000 | 16 per 1000 (95 % CI 11 to 23) | OR 1.56 (95% CI 1.08 to 2.24) | 172 (95% CI 94 to 927) |
| Outcome | Participants (studies) | Routine practice* | Opportunistic screening* | Relative effect | Number needed to screen |
| Number of new diagnoses (follow up 12 months) | 9 088 (1 study) | 10 per 1000 | 16 per 1000 (95% CI 11 to 23) | OR 1.57 (95% CI 1.1 to 2.26) | 167 (95% CI 92 to 806) |
| *Illustrative comparative number of new diagnoses: assumed - routine practie; corresponding - screening | |||||
Uptake of screening was higher for systematic screening than for opportunistic screening, and within both interventions the uptake was higher for men and the 65 to 74 age group compared to people over 75 years. No safety issues or complications were reported. There were insufficient data to compare the effectiveness of screening programmes in different healthcare settings. Systematic screening was more costly than opportunistic screening.
Comment: The quality of evidence is downgraded by study limitations (unclear allocation concealment and lack of blinding).
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