Introduction: The Danish Civil Registration System (CRS) was established in 1968, and all persons alive and living in Denmark were registered for administrative use. Content: CRS includes individual information on the unique personal identification number, name, gender, date of birth, place of birth, citizenship, identity of parents and continuously updated information on vital status, place of residence and spouses. Validity and coverage: Since 1968, CRS has recorded current and historical information on all persons living in Denmark. Among persons born in Denmark in 1960 or later it contains complete information on maternal identity. For women born in Denmark in April 1935 or later it contains complete information on all their children. CRS contains complete information on immigrations and emigrations from 1969 onwards, permanent residence in a Danish municipality from 1971 onwards, and full address in Denmark from 1977 onwards. Conclusion: CRS in connection with other registers and biobanks will continue to provide the basis for significant knowledge relevant to the aetiological understanding and possible prevention of human diseases.

https://journals.sagepub.com/doi/pdf/10.1177/1403494810387965

The Danish civil registration system

Introduction: The Danish National Patient Register (NPR) was established in 1977, and it is considered to be the finest of its kind internationally. Content: At the onset the register included information on inpatient in somatic wards. The content of the register has gradually been expanded, and since 2007 the register has included information on all patients in Danish hospitals. Validity and coverage: Although the NPR is overall a sound data source, both the content and the definitions of single variables have changed over time. Changes in the organisation and provision of health services may affect both the type and the completeness of registrations. Conclusion: The NPR is a unique data source. Researchers using the data should carefully consider potential fallacies in the data before drawing conclusions.

https://journals.sagepub.com/doi/pdf/10.1177/1403494811401482

The Danish National Patient Register

Background
The Danish National Patient Registry (DNPR) is one of the world’s oldest nationwide hospital registries and is used extensively for research. Many studies have validated algorithms for identifying health events in the DNPR, but the reports are fragmented and no overview exists.

/pdf/the-danish-national-patient-registry-a-review-of-content-1tblzc3eff.pdf

The Danish National Patient Registry: a review of content, data quality, and research potential.

Background The Danish Civil Registration System (CRS) was established in 1968, where all persons alive and living in Denmark were registered. Among many other variables, it includes individual information on personal identification number, gender, date of birth, place of birth, place of residence, citizenship, continuously updated information on vital status, and the identity of parents and spouses. Methods To evaluate the quality and completeness of the information recorded on persons in the CRS, we considered all persons registered on November 4, 2005, i.e. all persons who were alive and resident in Denmark at least one day from April 2, 1968 to November 4, 2005, or in Greenland from May 1, 1972 to November 4, 2005. Results A total of 8,176,097 persons were registered. On November 4, 2005, 5,427,687 (66.4%) were alive and resident in Denmark, 56,920 (0.7%) were alive and resident in Greenland, 2,141,373 (26.2%) were dead, 21,160 (0.3%) had disappeared, and 528,957 (6.5%) had emigrated. Among persons born in Denmark 1960 or later the CRS contains complete information on maternal identity. Among persons born in Denmark 1970 or later the CRS contains complete information on paternal identity. Among women born in Denmark April 1935 or later the CRS contains complete information on all their children. Among males born in Denmark April 1945 or later the CRS contains complete information on all their children. The CRS contains complete information on: a) immigrations and emigrations from 1971 onwards, b) permanent residence in a Danish municipality from 1971 onwards, c) permanent residence in a municipality in Greenland from May 1972 onwards, and d) full address in Denmark from 1977 onwards. Conclusion Data from the CRS is an important research tool in epidemiological research, which enables Danish researchers to carry out representative population-based studies on e.g. the potential clustering of disease and death in families and the potential association between residence and disease and death.

The Danish Civil Registration System. A cohort of eight million persons.

Higher BMI during childhood is associated with an increased risk of CHD in adulthood. The associations are stronger in boys than in girls and increase with the age of the child in both sexes. Our findings suggest that as children are becoming heavier worldwide, greater numbers of them are at risk of having CHD in adulthood.

/pdf/childhood-body-mass-index-and-the-risk-of-coronary-heart-1b62ll4umc.pdf

Childhood body-mass index and the risk of coronary heart disease in adulthood

The Danish National Hospital Register (LPR) has collected nationwide data on all somatic hospital admissions since 1977, and since 1995 data on outpatients and emergency patients have been included as well. Numerous research projects have been undertaken in the national Danish context as well as in collaboration with international teams, and the LPR is truly a valuable source of data for health sciences, especially in epidemiology, health services research and clinical research. Nearly complete registration of somatic hospital events in Denmark is combined with ideal conditions for longterm follow-up due to the existence of a national system of unique person identification in a population of relative demographic stability. Examples of studies are provided for illustration within three main areas: I: Using LPR for surveillance of the occurrence of diseases and of surgical procedures, II: Using the Register as a sampling frame for longitudinal population based and clinical research, and III: Using the Register as a data source for monitoring outcomes. Data available from the Register as well as studies of the validity of the data are mentioned, and it is described how researchers may get access to the Register. The Danish National Hospital Register is well suited to contribute to international comparative studies with relevance for evidence-based medicine.

J Jørgensen

Papers

The Danish National Hospital Register. A valuable source of data for modern health sciences.