Nordic Health Registry-Based Research: A Review of Health Care Systems and Key Registries

Abstract

The Nordic countries are Denmark, Finland, Iceland, Norway, and Sweden and comprise a total population of approximately 27 million. The countries provide unique opportunities for joint health registry-based research in large populations with long and complete follow-up, facilitated by shared features, such as the tax-funded and public health care systems, the similar population-based registries, and the personal identity number as unique identifier of all citizens. In this review, we provide an introduction to the health care systems, key registries, and how to navigate the practical and ethical aspects of setting up such studies. For each country, we provide an overview of population statistics and health care expenditures, and describe the operational and administrative organization of the health care system. The Nordic registries provide population-based, routine, and prospective data on individuals lives and health with virtually complete follow-up and exact censoring information. We briefly describe the total population registries, birth registries, patient registries, cancer registries, prescription registries, and causes of death registries with a focus on period of coverage, selected key variables, and potential limitations. Lastly, we discuss some practical and legal perspectives. The potential of joint research is not fully exploited, mainly due to legal and practical difficulties in, for example, cross-border sharing of data. Future tasks include clear and transparent legal pathways and a framework by which practical aspects are facilitated.

Type 2 diabetes classification: a data-driven cluster study of the Danish Centre for Strategic Research in Type 2 Diabetes (DD2) cohort

“…Denmark has a free tax supported healthcare system. 6 7 All individuals aged ≥18 years with new clinically diagnosed T2D in Denmark after 1 January 2009, with or without initiation of glucose-lowering therapy, are eligible for inclusion in the DD2 cohort and biobank ( online supplemental table S1 ). At enrollment, interview and clinical examination data for each patient are recorded, and blood and urine samples are obtained.…”

Periconceptional Use of Phthalate-Containing Medications and Secondary Sex Ratio

“…Using personal identifiers assigned to all Danish residents, we linked data from several Danish health registries (Laugesen et al 2021). Data on medication excipients in pharmaceuticals marketed during the period 2004-2017 from the Danish Medicines Agency were linked with individual-level prescription data from the Prescription Register.…”

Association between having a pregnancy complicated by vaginal bleeding and risk of cancer

“…[30] Hospital admissions are available in the DNPR from 1977, while outpatient clinic and emergency room visits are recorded from 1995 onwards. [30,31] Admissions and outpatient specialist visits due to psychiatric conditions are captured by the Psychiatric Central Research Register [32] and were available in this study from 1995. The Danish National Prescription Registry [33] captures data on prescribed medication dispensings from 1995 onwards and records the Anatomical Therapeutic Classification (ATC) codes of the dispensed drugs and the dates when the prescriptions were redeemed.…”