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Register-based research: information, tools, examples

The current pandemic has highlighted the importance of accelerating research in order to meet the global health challenge. Knowledge about COVID-19 has, over the last two years, rapidly increased through research studies, pre-clinical studies, clinical trials, and register-based studies using real-patient data.

Register-based data can contribute with important real-patient data aspects to research and add a new dimension to the field. Linking register-based data, clinical data, and biobank samples can give insights into not yet not elucidated parts of COVID-19 disease urgently warranted. To facilitate register-based research, on this page we provide information, guidelines, and tools to support.

Subset of useful registers

The table below is an overview of a number of different national public authority registers and national quality registers that may be useful for COVID-19 related register-based research. Please note that the webpages of some of the registers listed below are only are available in Swedish.

Ordering register data

Note that in case of some registers information is only available in Swedish.

Ongoing research projects

Below is a manually curated overview of research projects using Register data that are funded by major funding agencies in Sweden. As it is manually curated, the list may not be exhaustive and new projects will be added as soon as possible. If you think that your project should be listed here but isn’t, please get in touch with us. For a list of all research projects funded by major funding agencies in Sweden see this section of the portal.

Project title Principal investigator PI affiliation Funder
COVID-19 – a population-based project of ICU patients Emma Larsson Karolinska Institute SciLifeLab / Knut and Alice Wallenberg Foundation
Characterization of ICU treated COVID patients in Sweden Jonathan Grip Karolinska Institute SciLifeLab / Knut and Alice Wallenberg Foundation
Register-based large-scale national population study to monitor Covid-19 vaccination effectiveness and safety (RECOVAC) Fredrik Nyberg University of Gothenburg SciLifeLab / Knut and Alice Wallenberg Foundation
Organization and response to covid-19 of municipal health and social care of older people – impact on mortality and health care utilization in Region Stockholm Bo Burström Karolinska Institute Swedish Research Council
Collateral damage of COVID-19 in older adults: short and long-term health consequences of the epidemic outbreak Laura Fratiglioni Karolinska Institute Swedish Research Council
Targeting the most severely affected in the COVID-19 pandemic: older adults’ medications and other crucial factors in large nationwide data Kristina Johnell Karolinska Institute Swedish Research Council
Covid-19 epidemic in Sweden and cardiometabolic disease: using available data from Swedish registers. Annika Rosengren University of Gothenburg Swedish Research Council
Covid-19 and androgen deprivation therapy for prostate cancer. Populationbased studies Pär Stattin Uppsala University Swedish Research Council
Addressing the smoking paradox in the etiology of COVID-19 through population-based studies Maria Rosaria Galanti Karolinska Institute NordForsk
COVID-19 vaccination in immuno-suppressed individuals: An interdisciplinary collaboration to obtain clinical and mechanistic insight into lasting immunity against SARS-CoV-2 infection Soo Aleman Karolinska Institute Swedish Research Council
Register studies and immunological effect studies of COVID-19 vaccination and build-up of infrastructure for pandemic preparedness at national level (RE-VISION) Magnus Gisslén University of Gothenburg Swedish Research Council
FASTER – National COVID-19 vaccine research platform Pontus Naucler Karolinska Institute Swedish Research Council

Examples of register-based research

Below is a list of preprints and published scientific journal articles using register-based data involving at least one author affiliated with a Swedish university or research institute. Note that this list is based on a manually curated database and, as such, may not be exhaustive. If you think that a publication should be listed here but isn’t, or feel that information about a publication needs correction, please get in touch with us. For a list of all publications on COVID-19 and SARS-CoV-2 involving at least one author affiliated with a Swedish university or research institute see this section of the portal.

Publication Registers used
Stridsman C, Vanfleteren LEGW, Konradsen JR, Axelsson Fisk S, Pedroletti C, [...], Karlsson Sundbaum J
Eur Respir J 2101920
DOI: 10.1183/13993003.01920-2021
Grote L, Theorell-Haglöw J, Ulander M, Hedner J
Sleep Med Clin 16 (3) 409-416
DOI: 10.1016/j.jsmc.2021.05.008
Melander S, Almström J, Enlund G, Frykholm P
Paediatr Anaesth
DOI: 10.1111/pan.14203
Sultanian P, Lundgren P, Strömsöe A, Aune S, Bergström G, [...], Rawshani A
Eur Heart J 42 (11) 1094-1106
DOI: 10.1093/eurheartj/ehaa1067
Bergqvist R, Ahlqvist VH, Lundberg M, Hergens MP, Sundström J, [...], Magnusson C
PLoS Med 18 (10) e1003820
DOI: 10.1371/journal.pmed.1003820
Gémes K, Talbäck M, Modig K, Ahlbom A, Berglund A, [...], Matthews AA
Eur J Epidemiol 35 (5) 401-409
DOI: 10.1007/s10654-020-00646-z


Sweden has a long tradition of record keeping of registers containing person data and many of the health registers in Sweden have data from the 1950s and forward. A register contains personal data ( health data, demographic, socioeconomic etc) connected to personal numbers, a unique identifier, that allows linking between registers. The registers are kept safe by different Register holders and all use has to adhere to GDPR and others laws.

A register-based study can be defined as “…an investigation of a research question or hypothesis using data from (a) new or existing registry(-ies) for patient recruitment and data collection…”. A register-based study may both be primary use of data and/ or secondary use of data. Secondary use of data means that the data in the register was originally collected for a different purpose. Register-based studies can be both clinical trials or a non-interventional trails/studies (EMA, Guideline of register-based studies, 2020). Using register-based data gives the researchers the possibility to study real-patient data and capture longitudinal data, in so called “real-world practice”. Importantly, register-based research covers all quantitative scientific disciplines, for example, Public Health, Sociology, Demography, Psychology, Statistics, Medical and Social Sciences, Health Economics etc. that use registers in research. Sweden has a long tradition of population-based registers, and the use of personal identity numbers allows linking between registers. Therefore, Sweden has the unique opportunity to use rich data from different population-registers for research aimed at better public health. - a hub for information about register-based data

The Swedish Research Council has set up a single national entry point for information and support for register-based data. is a website aimed at researcher who wish to use Swedish register-based data in their research. The website includes information about available registers, and guides the researchers in the register-based research process (identify, request, and use), and aims at making information about the legal requirements easily available. In most cases the data produced in register-based research cannot be openly shared (if data should be shared with a third party there is the need for a risk assessment), though new code may.

There are several types of registers available in Sweden (note that the webpages listed below are in Swedish):

Register Utilizer Tool (RUT)

The Swedish Research Council also operates the Register Utiliser Tool (RUT) that allows researchers to search and match metadata in registers from both register holding authorities and organizations, which facilitates the use of register-based data. All the registers made available in the tool are structures according to Generic Statistical Information Model (GSIM) which is a framework for metadata developed by the United Nations Economic Commission for Europe (UNECE).An important functionality in RUT is the possibility to search for variables without an exact name using the free text option, in addition search also allows searchers of specific terms or populations. Most of the metadata and concepts in RUT are in Swedish. Semantic mapping to international ontologies and terminologies has been carried out in some registers connected to RUT and is ongoing in other registers. Such mapping enables machine readability and multilingualism in the languages implemented by the ontologies or terminologies.During the pandemic, register-based data from, for example, the Swedish Intensive Care Registry (SIR), one of the Swedish national quality registers which include the number of inpatients with COVID-19 in Swedish intensive care departments, have proved important for both research and policy-making.

In summary, the RUT tool that makes the metadata searchable and contributes to making the registered registers more FAIR (Findable, Accessible, Interoperable and Reusable, for more information about FAIR see here). Note that though the tool is free of charge you need to use an email connected to a research institution, or to an authority or organization that holds registers to set up a RUT account.

Note: The information on this webpage is primarily based on available information from and