Procedure to obtain the data
There were considerable variations in the procedure to obtain the requested data in the different countries (table ). Approval of the project, based on a provided project description, by the agencies responsible for the death certificate data was sufficient to get the data files in Italy, Belgium, and Scotland. In the Netherlands this was also the case, but the office's data protection policy to prevent possible identification of individuals implied some restrictions in the use of the data, so that some variables could not be provided (e.g. marital status, place of residence), while aggregations needed to be made for others (e.g. age, cause of death). Data were provided relatively fast in these countries.
Procedure to obtain the databases
In other countries additional approvals were required next to those by the agencies responsible for the death certificate data: in Sweden by the National Board of Health and Welfare; in Denmark by the Danish Data Protection Agency (including an additional approval of access to micro data with a restriction to use the data only within Denmark); in England/Wales by the Micro release panel; and in Norway by the data protection agency and by the Social- and Public Health Department of the Ministry of Health.
In Denmark, Sweden, England/Wales and Norway, the time from the order of the data to the delivery exceeded (sometimes considerably) 6 months. No charges were asked for the datasets in Belgium (Flanders and Brussels), and Italy (all three regions). In the Netherlands, England/Wales and in Scotland the cost price was less than 1,000 euros, in Sweden over 2,500 euros and in Denmark over 3,500 euros.
Most recent year available and total number of deaths on the data file
The most recent year of the available full and error-checked databases -at the time of the initiation of the study (September 2004)- was 2003 for Flanders(BE), Brussels(BE), The Netherlands, Norway, Scotland (UK), and England/Wales (UK); 2002 for Tuscany (IT), Emilia Romagna (IT), the city of Milan (IT), and Sweden, and 2001 for Denmark.
Total number of deaths ranged from 10,108 in Brussels to 505,341 in England (table ).
Total number of deaths on the datafile and year of registration
Place of death information
The categories of the place of death variable on the death certificate data file corresponded in most countries with the categories that could be marked on the actual death certificates (table ). In the Netherlands it was most comprehensive, comprising the categories: hospital, psychiatric hospital, nursing home, home for older people, other institute, own home, and other. On the Belgian file, the place of death was divided in hospital, care home (which covers both nursing homes and homes for older people), home and other (subdivided in workplace, public road, or a textual specification by the physician). The Scotland data file comprised hospital (hospital, and joint user), care homes (residential homes, nursing homes, and contracturals), own home, other institution (prison, and homes), and other. The England and the Wales file distinguished hospitals, psychiatric hospitals, care homes (residential homes, and nursing homes), own home, and NHS and private hospices. In Norway hospitals and care homes were grouped in a same category on the death certificate.
Available categories of the variable 'place of death' on the death statistics database
However, in three countries the place of death variable on the dataset did not contain all categories that could be marked by certifying physicians on the death certificate [see Additional file 1
]. The Italian datasets only made a distinction between 'home' and 'other', while the category 'hospital' from the death certificate was not recorded. The Danish data file only distinguished 'hospitals', 'institutions (but not hospitals)', and 'other', while 'home' could also be marked on the death certificate. In Sweden, place of death, while a certified variable, was not even recorded at all on the death certificate data file. However, 'hospital', 'psychiatric hospital' or 'other' could be deduced from the postcodes of the parish of death, as these institutions have their own postcodes.
Other variables, potentially associated with place of death
In Belgium and in Italy most desired clinical and socio-demographic information was directly available via the countries' death certificate data (table ). In other countries the clinical and socio-demographic information directly available via the death certificate data was more limited, but in several countries linkages could be made (via unique identifiers) with other population databases. The living environment of the deceased was however not available in Norway, Sweden, and Scotland. In England and Wales the living environment and the civil status of the deceased, recorded in census data, were not linked to the death certificate data due to privacy rules. The level of education could not be retrieved in The Netherlands and in the UK, but in England, Wales and Scotland the social class based on the last occupation (i.e. NS-SEC code) was available for all deaths below 75 years.
variables potentially associated with place of death on the data-file
In all countries, the cause of death variable was provided as an ICD-10 (3 digits) coded variable, except in The Netherlands and in Italy, where the data protection policies called for certain aggregation. In these countries we negotiated to have 27 pre-determined aggregated cause of death categories, for which we in broad outlines followed the instruction manual by the U.S. Department of Health and Human Services [43
Besides socio-demographic and clinical variables we also aimed to include a number of residence and healthcare system characteristics. As the municipality (or the parish, council, or local authority) of residence was available on the data files, the variables urbanisation, contextual SES-measures, and number of hospital beds per 1,000 inhabitants were operationalized by linking existing statistics to this place of residence of the deceased.
The Dutch data protection policy, however, did not allow providing us a database containing the municipality of residence of the deceased. At our request the inclusion of the residence characteristics was therefore done in advance by the Dutch Central Bureau of Statistics.