What factors explain the differences in morbidity estimations among general practice registration networks in the Netherlands? A first analysis

Figures & data

Figure 1.  Factors influencing morbidity figures of general practice based registration networks.

Table I.  Outline of 11 Dutch general practice registration networks (GPRNs).

	ANH-VUmc	CMR-N	HAG-net-AMC	HNU	IPCI	LINH	RNG	RNH	RNUH- LEO	SMILE	Trans
Healthcare system
Localization	Amsterdam, Amstelveen, and Haarlem	Nijmegen and surrounding area	Care area AMC Amsterdam	Province Utrecht	Throughout the Netherlands	Dutch representation	Groningen, Hoogezand-Sappemeer, and Hoogeveen	Province of Limburg	Leiden and surrounding area	Eindhoven	Amstelveen and Franeker
Methodological aspects
- Sample size
Size	70 000	13 500	57 000	56 210	600 000	350 000	30 000	87 780	30 000	56 000	13 160
No. of GPs/practices	47/12	11/4	44/37	35/22	362/not counted	160/80	17/6	65/22	20/4	32/9	8/5
- General information
Goal	Improving quality of family medicine	Generating epidemiologic data for diseases	Providing a sample framework for scientific research	Collecting longitudinal data for scientific research	Collecting data from primary care for post-marketing surveillance	Providing information about GP care, quality of care, and public health	Systematic collection of information for patient care	Providing a sample framework for scientific research	Supporting scientific research, education, and GP care in general	Collecting hybrid data for research and sampling framework from questionnaires and GP care	Formulating, characterizing, and describing GP-based epidemiology
Type of network	Problem list and contact based GPRN	Contact based GPRN	Problem list based GPRN	Contact based GPRN	Contact based GPRN	Contact based GPRN	Problem list and contact based GPRN	Problem list based GPRN	Problem list and contact based GPRN	Problem list and contact based GPRN, and patient questionnaires	Contact based GPRN
Classification^#	ICPC	E-codes	ICPC	ICPC-2	ICPC	ICPC	ICPC	ICPC-1	ICPC-1	ICPC-1	ICPC-2/ ICD-10
- Definitions
Numerator	Episodes^a and problems^b	Episodes^c	Problems^b	Episodes^a	Complete records^d	Contacts^e	Episodes^f	Problems^b	Episodes^a and problems^b	Episodes^a and problems^b	Episodes^g
- Data available
Recorded information	Morbidity, prescriptions, and referrals	Morbidity, referrals, and hospital admission	Morbidity, prescriptions, and intervention	Morbidity, prescriptions, referrals, and intervention	Morbidity, complete records	Morbidity, prescriptions, referrals, and intervention	Morbidity, prescriptions, referrals, type of contact	Morbidity, prescriptions, medication dossier	Morbidity, prescriptions, medical history, diagnostic dossier, and referrals	Morbidity, prescriptions, referrals, number and type of contacts	Morbidity, all proceedings in practice^§
Recording: out-of-office hours, telephone contact, visits	No agreements	Out-of-hours and telephone contact, and visits	Differs per location	Telephonic contact and visits, but incomplete	No agreements	Telephonic and e-mail contact, and visits	Out-of-hours and telephone contact, and visits	No	Out-of-hours (except one practice) and telephone contact, and visits	Telephone contact and visits	Yes, all out-of-office hours only employee GP
Recorded contact with other employees?*	Varies between practice and GPIS	Yes Assistant	Yes Assistant	Yes Assistant	Yes But no agreement	Yes Assistant and nurse practitioner	Yes Assistant, nurse practitioner, and locum tenens	Contacts are not used in database	Yes Assistant, physician assistant, and locum tenens	Yes	Yes Assistant, physician assistant, and locum tenens
- Quality assurance
Control of data after extraction	Yes Impossible or illogical combinations	Yes File size and misclassifications	Yes Impossible or illogical combinations and missing values	Yes ID codes and completeness	Yes Completeness and internal consistency	Yes Completeness and internal consistency	No	Yes Impossible or illogical combinations or values	Yes Population, impossible values, missing links, completeness, and doubles	No (in future)	Yes Doubles
Classification agreements	Instruction GP	Training GP	Internal training GP	Expertise promotion	Absence of paper registration	Explicit documentation, introduction period for new GPs	Explicit documentation	Training GP, coding assistance (RNH web, RNH assistant program, help file)	Internal training GP and explicit documentation	Instruction GP	Inclusion and exclusion criteria registered in ICPC-2
Feedback concerning data to GP	?	Yes	Yes	Yes GP info-net	Yes	Yes	Yes + annual report and newsletter	Yes	Yes	Yes	Yes
Meetings	Yes Monthly and 2 per year	Yes Monthly	Yes 2 per year	Yes 5 per year	Occasionally	Optional Once a year	Yes 2 per year and 1 weekend	Yes 2 per year	Optional Once a year	Optional	Yes, 6-weekly and 1 weekend
Content of meetings	Education, GP workshops	Classification difficulties, consensus	Quality of the registration, special items	Education and registration	Scientific topics	Not applicable	Registration problems	Consensus	Not applicable	Registration difficulties, benchmarking	Classification problems, special items
Information system
software package	OmniHIS, MicroHIS, and Medicom	Promedico	Mira and MicroHIS 8	MicroHIS and Promedico	Elias, Promedico, MicroHIS, Medicom, and HetHIS	Arcos, Mira, Promedico, OmniHIS, MicroHIS, Elias, and Medicom	MicroHIS	MicroHIS and Zorgdossier	Medicom	Medicom	TransHIS
Patient characteristics
Patient characteristics	Year of birth, gender, zip code, patient category (fixed or not fixed)	Gender, age, social class, education level, family situation, occupation, zip code	Date of birth, gender, family situation (ethnicity)	Date of birth, gender, family situation, zip code	Gender, age, family situation, patient category (fixed or passer-by)	Date of birth, gender, family situation, zip code, patient category (fixed or passer-by), GP code	Date of birth, gender, zip code, GP code	Date of birth, gender, family situation, education (>25 years old), zip code, status fixed or not	Age, gender, number of family members	Date of birth, gender, educational level, marital status, living arrangement, zip code	Date of birth, gender, family situation, zip code

^#Classification system according to the GPRN.

*Employees, other than practice GPs, who record data in the EMD, according to the GPRN.

^aCounting 1-year prevalence, thus after at least one GP–patient contact in the reference year.

^bUse all diseases or complaints which are permanent, chronic, or recurrent, or which need to be brought to GP's attention.

^cUse all information about morbidity a GP receives, aditionally chronic and permanent disease episodes are continued in the following years.

^dDepends on the research question: whole record information is possible (free text, diagnoses, prescriptions, specialist letters, etc.).

^eEpisode construction after collection in database.

^fStart with morbidity episodes, with possible completion with prescriptions, referrals, and interventions.

^gUse all information about what takes place in general practice.

^§All proceedings in practice, including type of contact, reason for contact, episode-of-care status, coding changes, referrals, test results, interventions, prescriptions, etc.

Table II.  Box 1. Prevalence rates of rheumatoid arthritis from five general practice registration networks (GPRNs) in the Netherlands. The National Institute for Public Health and the Environment uses information about diseases derived from GPRNs for the estimation of morbidity rates presented in the National Public Health Compass [14]. Prevalence^‡ rheumatoid arthritis (per 1000 patients)

	CMR-Nijmegen	LINH	RNH	RNUH LEO	Transition Project
Men	5.11	2.97	9.40	6.83	3.06
Women	6.40	5.92	13.49	13.19	7.18

^‡These rates are based on data from GPRNs, which were available in 2005.

Table III.  Box 2. Ten Dutch general practice registration networks.

Abbreviation	Full name (Dutch)	Full name (English)
ANH-VUmc	Academisch Netwerk Huisartsgeneeskunde, Vrije Universitair medisch centrum	Academic General Practice Network of VU University Medical Centre
CMR-N	Continue Morbiditeit Registratie Nijmegen	Continuous Morbidity Registration Nijmegen
HAG-net-AMC	Huisartsen Netwerk Academisch Medisch Centrum	General Practice Network Academic Medical Centre
IPCI	–	Integrated Primary Care Information
LINH	Landelijk Informatie Netwerk Huisartsenzorg	Netherlands Information Network of General Practice
RNG	Registratie netwerk Groningen	Registration Network Groningen
RNH	Registratie net huisartspraktijken	Registration Network Family Practices
RNUH LEO	Registratie Netwerk Universitaire Huisartspraktijken Leiden en omgeving	Registration Network of General Practitioners Associated with Leiden University
SMILE	Studie naar Medische Informatie en Leefwijzen in Eindhoven	Study into Medical Information and Lifestyle in Eindhoven
Trans	Transitie Project	Transition Project
HNU	Huisartsen Netwerk Utrecht	The Utrecht Network of General Practitioners

Poos MJJC, Gijsen R. Reumatoide arthritis. Omvang van het probleem. Achtergronden en details bij cijfers uit huisartsregistraties. National Public Health Compass (Nationaal Kompas Volksgezondheid), part of the Dutch Public Health Status and Forecasts, version 3.11.1 Bilthoven: RIVM; 8 November, 2007. URL: www.nationaalkompas.nl.

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