Open Access Open Badges Research article

Usefulness of primary care electronic networks to assess the incidence of chlamydia, diagnosed by general practitioners

Anita WM Suijkerbuijk1*, Ingrid VF van den Broek1, Henk J Brouwer2, Ann M Vanrolleghem3, Johanna HK Joosten4, Robert A Verheij5, Marianne AB van der Sande16 and Mirjam EE Kretzschmar16

Author Affiliations

1 Centre for Infectious Disease Control, RIVM National Institute of Public Health and the Environment, Bilthoven, The Netherlands

2 Department of General Practice, Academic Medical Center-University of Amsterdam, The Netherlands

3 Department of Medical Informatics, Erasmus University Medical Centre, Rotterdam, The Netherlands

4 Academic General Practice Network VUmc, Free University Medical Centre, Amsterdam, The Netherlands

5 NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands

6 Julius Centre for Health Sciences and Primary Care, University Medical Centre Utrecht, Utrecht, The Netherlands

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BMC Family Practice 2011, 12:72  doi:10.1186/1471-2296-12-72

Published: 8 July 2011



Chlamydia is the most common curable sexually transmitted infection (STI) in the Netherlands. The majority of chlamydia diagnoses are made by general practitioners (GPs). Baseline data from primary care will facilitate the future evaluation of the ongoing large population-based screening in the Netherlands. The aim of this study was to assess the usefulness of electronic medical records for monitoring the incidence of chlamydia cases diagnosed in primary care in the Netherlands.


In the electronic records of two regional and two national networks, we identified chlamydia diagnoses by means of ICPC codes (International Classification of Primary Care), laboratory results in free text and the prescription of antibiotics. The year of study was 2007 for the two regional networks and one national network, for the other national network the year of study was 2005. We calculated the incidence of diagnosed chlamydia cases per sex, age group and degree of urbanization.


A large diversity was observed in the way chlamydia episodes were coded in the four different GP networks and how easily information concerning chlamydia diagnoses could be extracted. The overall incidence ranged from 103.2/100,000 to 590.2/100,000. Differences were partly related to differences between patient populations. Nevertheless, we observed similar trends in the incidence of chlamydia diagnoses in all networks and findings were in line with earlier reports.


Electronic patient records, originally intended for individual patient care in general practice, can be an additional source of data for monitoring chlamydia incidence in primary care and can be of use in assessing the future impact of population-based chlamydia screening programs. To increase the usefulness of data we recommend more efforts to standardize registration by (specific) ICPC code and laboratory results across the existing GP networks.