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Incidence and prevalence of autoimmune disease in the Swedish National Patient Register

Bergman, David ; Sundquist, Kristina LU ; Segelmark, Mårten LU orcid ; Svedbom, Axel ; Sun, Jiangwei ; Piehl, Fredrik ; Yuan, Shuai ; Kämpe, Olle ; Brodin, Petter and Ebrahimi, Fahim , et al. (2026) In European Journal of Epidemiology 41(3). p.367-375
Abstract

Background: Standardized definitions of autoimmune disease (AD) are lacking. Therefore, we aim to propose a definition of AD for register-based research and estimate the burden of AD in Sweden as registered in the National Patient Register (NPR) from 1980 to 2023. Methods: Leveraging the NPR, we defined AD as having at least two relevant International Classification of Diseases (ICD) codes representing AD. These codes could either represent the same disease or two different diseases. Age-standardized and age-specific incidence rates (IRs) of AD were calculated, along with prevalence on December 31, 2023. Results: From 1980 to 2023, the mean age-standardized IR of AD was 318 cases per 100,000 person-years (95% CI: 294–342). The IR... (More)

Background: Standardized definitions of autoimmune disease (AD) are lacking. Therefore, we aim to propose a definition of AD for register-based research and estimate the burden of AD in Sweden as registered in the National Patient Register (NPR) from 1980 to 2023. Methods: Leveraging the NPR, we defined AD as having at least two relevant International Classification of Diseases (ICD) codes representing AD. These codes could either represent the same disease or two different diseases. Age-standardized and age-specific incidence rates (IRs) of AD were calculated, along with prevalence on December 31, 2023. Results: From 1980 to 2023, the mean age-standardized IR of AD was 318 cases per 100,000 person-years (95% CI: 294–342). The IR decreased with the introduction of ICD-10 (1997), but then sharply increased in 2001 following the addition of specialized outpatient data to the NPR that year, likely reflecting improved case ascertainment rather than a sudden true rise in incidence. As of December 31, 2023, the prevalence of AD in Sweden was 6.6% overall, 7.9% in adults, and 1.5% in children. Conclusions: In a nationwide study spanning more than 40 years, the IR of AD was 318 per 100,000 person-years but with substantial variation correlating to administrative changes in coding and content of the NPR. In 2023, the point prevalence of AD in Sweden was 1 in 15 individuals across all ages, 1 in 13 adults, and 1 in 67 children.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Autoimmunity, Epidemiology, Incidence
in
European Journal of Epidemiology
volume
41
issue
3
pages
367 - 375
publisher
Springer
external identifiers
  • scopus:105030675622
  • pmid:41721992
ISSN
0393-2990
DOI
10.1007/s10654-026-01369-3
language
English
LU publication?
yes
id
9b47927d-409a-42a8-86b6-23177fa1b677
date added to LUP
2026-04-21 15:39:12
date last changed
2026-06-10 09:11:32
@article{9b47927d-409a-42a8-86b6-23177fa1b677,
  abstract     = {{<p>Background: Standardized definitions of autoimmune disease (AD) are lacking. Therefore, we aim to propose a definition of AD for register-based research and estimate the burden of AD in Sweden as registered in the National Patient Register (NPR) from 1980 to 2023. Methods: Leveraging the NPR, we defined AD as having at least two relevant International Classification of Diseases (ICD) codes representing AD. These codes could either represent the same disease or two different diseases. Age-standardized and age-specific incidence rates (IRs) of AD were calculated, along with prevalence on December 31, 2023. Results: From 1980 to 2023, the mean age-standardized IR of AD was 318 cases per 100,000 person-years (95% CI: 294–342). The IR decreased with the introduction of ICD-10 (1997), but then sharply increased in 2001 following the addition of specialized outpatient data to the NPR that year, likely reflecting improved case ascertainment rather than a sudden true rise in incidence. As of December 31, 2023, the prevalence of AD in Sweden was 6.6% overall, 7.9% in adults, and 1.5% in children. Conclusions: In a nationwide study spanning more than 40 years, the IR of AD was 318 per 100,000 person-years but with substantial variation correlating to administrative changes in coding and content of the NPR. In 2023, the point prevalence of AD in Sweden was 1 in 15 individuals across all ages, 1 in 13 adults, and 1 in 67 children.</p>}},
  author       = {{Bergman, David and Sundquist, Kristina and Segelmark, Mårten and Svedbom, Axel and Sun, Jiangwei and Piehl, Fredrik and Yuan, Shuai and Kämpe, Olle and Brodin, Petter and Ebrahimi, Fahim and Askling, Johan and Ludvigsson, Jonas F.}},
  issn         = {{0393-2990}},
  keywords     = {{Autoimmunity; Epidemiology; Incidence}},
  language     = {{eng}},
  number       = {{3}},
  pages        = {{367--375}},
  publisher    = {{Springer}},
  series       = {{European Journal of Epidemiology}},
  title        = {{Incidence and prevalence of autoimmune disease in the Swedish National Patient Register}},
  url          = {{http://dx.doi.org/10.1007/s10654-026-01369-3}},
  doi          = {{10.1007/s10654-026-01369-3}},
  volume       = {{41}},
  year         = {{2026}},
}