As no universally agreed on operational definitions currently exist for categorising migrants, the following definition developed by the MEHO-partners was employed: "A migrant is any person who migrated to the current EU-27 countries from outside the EU-15 member states (the 15 EU member states before the expansion in 2004), while further excluding North America and Australasia but including the post World War II guest workers from the Southern European countries periphery (e.g. Italy, Greece, and Turkey) and re-settlers from the former countries of the Soviet Union, and is staying as a resident (not a visitor, asylum seeker, temporary worker or student)" . Thus, large group of migrant workers from countries like Italy and Greece are included in the definition in spite of the long lasting EU membership of their country of origin. This is primarily motivated by the expectation of the MEHO partners that these migrant groups might be disadvantaged healthwise and therefore should be included in the various parts of the MEHO project. Furthermore, by using this definition, ethnic minorities living in a country for generations were excluded.
For the purpose of gaining knowledge about existing registries on health care utilization which includes information allowing for identification of permanently settled migrants in the EU countries, we designed a questionnaire. Due to national differences in registry and classification systems, we pilot tested the questionnaire among our collaboration partners, mainly researchers and national health authorities, in selected EU countries (Denmark, Germany, Italy, the Netherlands, and the UK). The questionnaire contained information on healthcare utilization registry sources including background information of registry such as demographic catchment area, number of records, delimitation of data, and registry format; availability of health care utilization information; availability of identification of migrants; availability of demographic and socio-economic information; limitations of data; and access to the registry.
We collected contact information of members of the Statistical Programme Committee network group, coordinated by EUROSTAT, which represents the official channel for statistical information in each EU country to whom we sent the questionnaire by email including a cover letter which explained the objectives in details, and that the research project was part of the MEHO-project . Furthermore, it was specified that accurate and complete information was extremely important for the development of this research project. Finally, it was outlined that if the receiver of the questionnaire did not represent the relevant institution, the receiver was kindly asked to provide us with contact information about who we should contact instead in the country in question.
After the deadline for the reply of the questionnaire specified in the cover letter, a reminder was sent along with the questionnaire. This procedure was repeated three times for countries not responding. Nevertheless, after four reminders, Italy, Malta, Spain, and the UK still did not respond (or did not respond with complete information). For Italy and Malta, we received the information on registries on healthcare utilization from another survey on general information on registries and survey data on migrant health that was conducted by Agency of Public Health, Lazio Legion, Italy in 2007/8 within the MEHO-project. Furthermore, we contacted researchers in Spain and the UK with expertise within healthcare utilization and migrant health with whom we had a personal contact. Through our contacts in Spain, the Health Ministry of Spain provided us with the information regarding national registries in Spain. For the UK, we only received information through our personal contacts; however, the different informants from the UK all concluded the same regarding availability of the registries. Finally, we double-checked all our collected information on healthcare utilization registries with information from the general survey of 2007/8. If a mismatch of the information occurred (in three cases: Austria, Belgium, and Czech Republic), we contacted the respondents for a clarification. All information on the registries was collected from September 2008-May 2009.
Criteria for registries to be listed in this overview were: 1) information on utilization of at least one healthcare service should be covered including a) in-patient hospital care utilization such as hospital admission and length of stay; b) out-patient care utilization such as ambulatory contacts, emergency room contacts, and contact to general practitioners; c) surgical operation and procedures; and d) medicine use; 2) information on migrant status should be included by at least one of the following indicators either directly or by linkage: country of birth, mother's country of birth, father's country of birth, citizenship, mother's citizenship, or father's citizenship according to the MEHO-definition; 3) the registry should have preferably national coverage or at least regional coverage; 4) the registry should include the general population and not a population sub-group e.g. infants, children, etc.
Registries on healthcare use for specific diagnoses or conditions e.g. reproductive health were excluded in order to generate a general overview.