Introduction: Disease registers and electronic health records are valuable resources for disease surveillance and research but can be limited by variation in data quality over time. Quality may be limited in terms of the accuracy of clinical information, of the internal linkage that supports person-based analysis of most administrative datasets, or by errors in linkage between multiple datasets.
Objectives: By linking the National Down Syndrome Cytogenetic Register (NDSCR) to Hospital Episode Statistics for England (HES), we aimed to assess the quality of each and establish a consistent approach for analysis of trends in prevalence of Down's syndrome among live births in England.
Methods: Probabilistic record linkage of NDSCR to HES for the period 1998-2013 was supported by linkage of babies to mothers within HES. Comparison of prevalence estimates in England were made using NDSCR only, HES data only, and linked data. Capture-recapture analysis and quantitative bias analysis were used to account for potential errors, including false positive diagnostic codes, unrecorded diagnoses, and linkage error.
Results: Analyses of single-source data indicated increasing live birth prevalence of Down's Syndrome, particularly in the analysis of HES. Linked data indicated a contrastingly stable prevalence of 12.3 (plausible range: 11.6-12.7) cases per 10 000 live births.
Conclusion: Case ascertainment in NDSCR improved slightly over time, creating a picture of slowly increasing prevalence. The emerging epidemic suggested by HES primarily reflects improving linkage within HES (assignment of unique patient identifiers to hospital episodes). Administrative data are valuable but trends should be interpreted with caution, and with assessment of data quality over time. Data linkage with quantitative bias analysis can provide more robust estimation and, in this case, stronger evidence that prevalence is not increasing. Routine linkage of administrative and register data can enhance the value of each.
Bibliographical noteFunding Information: This work was supported by the Economic and Social Research Council [grant number: ES/L007517/1], the Medical Research Council [grant number: London MR/ K006584/1], the NIHR Great Ormond Street Hospital Biomedical Research Centre, Health Data Research UK [RG] and The Wellcome Trust (grant number: 103975/A/14/Z; KH).
JM was Director of the National Downs Syndrome Cytogenetic Register at Queen Mary University of London until its integration into the National Congenital Anomaly and Rare Disease Registration Service at Public Health England in 2014. SS was the Registry Lead for the National Congenital Anomaly and Rare Disease Registration Service at the time of writing.
Open Access: Open Access under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/deed.en).
Publisher Copyright: 2019 © The Authors.
Citation: Doidge, James C., et al. "Prevalence of Down's Syndrome in England, 1998–2013: Comparison of linked surveillance data and electronic health records." International journal of population data science 5.1 (2020).
- Data linkage
- Disease surveillance
- Down's syndrome
- Electronic health records
- Linkage error