Ascertainment and accuracy of Down syndrome cases reported in congenital anomaly registers in England and Wales
- 1Department of Public Health and Primary Care, University of Cambridge, Institute of Public Health, Cambridge, UK
- 2Centre for Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, St Bartholomew’s and the London Queen Mary’s School of Medicine and Dentistry, London, UK
- Dr J K Morris, Centre for Environmental and Preventive Medicine, Wolfson Institute of Preventive Medicine, St Bartholomew’s and the London Queen Mary’s School of Medicine and Dentistry, Charterhouse Square, London, EC1M 6BQ, UK; j.k.morris{at}qmul.ac.uk
- Accepted 7 March 2008
- Published Online First 28 March 2008
Abstract
Objective: Congenital anomaly registers allow the rates of anomalies to be monitored and are essential for understanding their epidemiology. We estimate the ascertainment and accuracy of records of Down syndrome (DS) on national and regional registers in England and Wales.
Methods: Probabilistic record linkage was used to match records of DS from three sources: the National Down Syndrome Cytogenetic Register (NDSCR), seven regional members of the British Isles Network of Congenital Anomaly Registers (BINOCAR) and the National Congenital Anomaly System (NCAS). Capture-recapture methods were then used to estimate the ascertainment of each register.
Results: The NDSCR and BINOCAR registers ascertain around 95% of both pre-natally and post-natally diagnosed cases of DS. NCAS collects data only on births and ascertains 55% of cases of DS births, which is currently around 25% of all DS diagnoses. NCAS ascertainment varies according to whether a BINOCAR register covering the same area contributes information to NCAS, varying from 80% in areas where regional registers contribute to 50% where regional registers do not.
Conclusions: Active case finding through regional registers is essential for monitoring congenital anomalies. The ascertainment of the NDSCR and BINOCAR is sufficient to provide reliable epidemiology and surveillance of congenital anomalies, whereas that of NCAS is not.
Footnotes
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Funding: JM is director of the NDSCR, funded by the United Kingdom National Screening Committee. GS was supported by grant RAB04/PJ/03 from the Research Advisory Board of St Bartholomew’s and The Royal London Charitable Foundation. NorCAS and CAROBB are funded by the Department of Health Policy Research Programme (Disease register). EMSYCAR is funded by PCTS within East Midlands and South Yorkshire. CARIS is funded by the West Assembly Government.
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Competing interests: JM is Director of the NDSCR. GS has no competing interests.
