Quality of recording of diabetes in the UK: how does the GP's method of coding clinical data affect incidence estimates? Cross-sectional study using the CPRD database
Open Access
- 25 January 2017
- Vol. 7 (1), e012905
- https://doi.org/10.1136/bmjopen-2016-012905
Abstract
Objective To assess the effect of coding quality on estimates of the incidence of diabetes in the UK between 1995 and 2014. Design A cross-sectional analysis examining diabetes coding from 1995 to 2014 and how the choice of codes (diagnosis codes vs codes which suggest diagnosis) and quality of coding affect estimated incidence. Setting Routine primary care data from 684 practices contributing to the UK Clinical Practice Research Datalink (data contributed from Vision (INPS) practices). Main outcome measure Incidence rates of diabetes and how they are affected by (1) GP coding and (2) excluding ‘poor’ quality practices with at least 10% incident patients inaccurately coded between 2004 and 2014. Results Incidence rates and accuracy of coding varied widely between practices and the trends differed according to selected category of code. If diagnosis codes were used, the incidence of type 2 increased sharply until 2004 (when the UK Quality Outcomes Framework was introduced), and then flattened off, until 2009, after which they decreased. If non-diagnosis codes were included, the numbers continued to increase until 2012. Although coding quality improved over time, 15% of the 666 practices that contributed data between 2004 and 2014 were labelled ‘poor’ quality. When these practices were dropped from the analyses, the downward trend in the incidence of type 2 after 2009 became less marked and incidence rates were higher. Conclusions In contrast to some previous reports, diabetes incidence (based on diagnostic codes) appears not to have increased since 2004 in the UK. Choice of codes can make a significant difference to incidence estimates, as can quality of recording. Codes and data quality should be checked when assessing incidence rates using GP data.This publication has 16 references indexed in Scilit:
- Trends in incidence, prevalence and prescribing in type 2 diabetes mellitus between 2000 and 2013 in primary care: a retrospective cohort studyBMJ Open, 2016
- Structuring and coding in health care records: a qualitative analysis using diabetes as a case studyJournal of Innovation in Health Informatics, 2015
- The Growing Prevalence of Type 2 Diabetes: Increased Incidence or Improved Survival?Current Diabetes Reports, 2013
- The incidence of type 2 diabetes in the United Kingdom from 1991 to 2010Diabetes, Obesity and Metabolism, 2013
- Use of diverse electronic medical record systems to identify genetic risk for type 2 diabetes within a genome-wide association studyJournal of the American Medical Informatics Association, 2012
- Automated identification of miscoded and misclassified cases of diabetes from computer recordsDiabetic Medicine, 2011
- Judging nudging: can nudging improve population health?BMJ, 2011
- Effects of Pay for Performance on the Quality of Primary Care in EnglandThe New England Journal of Medicine, 2009
- Effect of the quality and outcomes framework on diabetes care in the United Kingdom: retrospective cohort studyBMJ, 2009
- Clinical information for research; the use of general practice databasesJournal of Public Health, 1999