Sammon, CJ;
Petersen, I;
(2016)
Backdating of events in electronic primary health care data: should one censor at the date of last data collection.
Pharmacoepidemiology and Drug Safety
, 25
(4)
pp. 378-384.
10.1002/pds.3981.
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Abstract
PURPOSE: Studies using primary care databases often censor follow-up at the date data are last collected from clinical computer systems (last collection date (LCD)). We explored whether this results in the selective exclusion of events entered in the electronic health records after their date of occurrence, that is, backdated events. METHODS: We used data from The Health Improvement Network (THIN). Using two versions of the database, we identified events that were entered into a later (THIN14) but not an earlier version of the database (THIN13) and investigated how the number of entries changed as a function of time since LCD. Times between events and the dates they were recorded were plotted as a function of time since the LCD in an effort to determine appropriate points at which to censor follow-up. RESULTS: There were 356 million eligible events in THIN14 and 355 million eligible events in THIN13. When comparing the two data sets, the proportion of missing events in THIN13 was highest in the month prior to the LCD (9.6%), decreasing to 5.2% at 6 months and 3.4% at 12 months. The proportion of missing events was largest for events typically diagnosed in secondary care such as neoplasms (28% in the month prior to LCD) and negligible for events typically diagnosed in primary care such as respiratory events (2% in the month prior to LCD). CONCLUSIONS: Studies using primary care databases, particularly those investigating events typically diagnosed outside primary care, should censor follow-up prior to the LCD to avoid underestimation of event rates.
| Type: | Article |
|---|---|
| Title: | Backdating of events in electronic primary health care data: should one censor at the date of last data collection |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/pds.3981 |
| Publisher version: | http://dx.doi.org/10.1002/pds.3981 |
| Language: | English |
| Additional information: | This is the peer reviewed version of the following article: Sammon, CJ; Petersen, I; (2016) Backdating of events in electronic primary health care data: should one censor at the date of last data collection. Pharmacoepidemiol Drug Saf 10.1002/pds.3981., which has been published in final form at DOI:10.1002/pds.3981. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving. |
| Keywords: | CPRD, THIN, censoring, database, epidemiology, pharmacoepidemiology, primary care |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Population Health Sciences > Institute of Epidemiology and Health > Primary Care and Population Health |
| URI: | https://discovery.ucl.ac.uk/id/eprint/1475658 |
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