AM, BB & MT are employees of EPIC, a license holder of THIN.
Version of Record online: 8 DEC 2008
Copyright © 2008 John Wiley & Sons, Ltd.
Pharmacoepidemiology and Drug Safety
Volume 18, Issue 1, pages 76–83, January 2009
How to Cite
Maguire, A., Blak, B. T. and Thompson, M. (2009), The importance of defining periods of complete mortality reporting for research using automated data from primary care. Pharmacoepidem. Drug Safe., 18: 76–83. doi: 10.1002/pds.1688
Conflict of interest was declared.
- Issue online: 29 DEC 2008
- Version of Record online: 8 DEC 2008
- Manuscript Accepted: 22 OCT 2008
- Manuscript Revised: 29 AUG 2008
- Manuscript Received: 28 MAR 2008
- data quality;
- primary care
To define periods of acceptable mortality reporting in primary care and to demonstrate through examples the implication for research using automated medical data.
Annual death counts were obtained for each primary care practice participating in The Health Improvement Network “THIN” (UK). Expected counts were calculated from national death rates, accounting for the practice's age/sex structure. The standardized mortality ratio (SMR) was calculated with 95% confidence intervals (CI). A visual review process was undertaken to assign the year from which the practice had acceptable mortality reporting (AMR). The process involved reviewer pairs who were blinded to each other's decisions. Patterns of death reporting were checked. The AMR year was applied as a filter to THIN data to assess its impact on the SMR.
For most practices the SMR was relatively stable and the AMR year was easily identified with 86% agreement between the blinded reviewer pairs. Applying the AMR to THIN removed under-reporting of death. However, the total computerized follow-up reduced from 37 to 32 million patient-years. Problematic death recording patterns included some practices keeping only live patient records when converting their software systems thereby creating ‘immortal periods’ prior to this moment, and peaks occurring when practices updated the vital status of their patients' records.
This is the first time that an external standard has been used to assess completeness of mortality in automated primary care data. The resulting AMR year provides a natural filter for research and avoids biases associated with ‘immortal periods’, record updating and under-reporting. Copyright © 2008 John Wiley & Sons, Ltd.