University of Oulu

J Paltta, H-K Heikkilä, L Pirilä, KK Eklund, J Huhtakangas, P Isomäki, O Kaipiainen-Seppänen, K Kristiansson, AS Havulinna, T Sokka-Isler, A Palomäki & for the FinnGen investigators (2023) The validity of rheumatoid arthritis diagnoses in Finnish biobanks, Scandinavian Journal of Rheumatology, 52:1, 1-9, DOI: 10.1080/03009742.2021.1967047

The validity of rheumatoid arthritis diagnoses in Finnish biobanks

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Author: Paltta, J.1; Heikkilä, H.-K.2; Pirilä, L.1;
Organizations: 1Centre for Rheumatology and Clinical Immunology, Division of Medicine, Turku University Hospital and University of Turku, Turku, Finland
2Centre for Rheumatic Diseases, Tampere University Hospital, Tampere, Finland
3Department of Rheumatology, Helsinki University Hospital, University of Helsinki and Orton Orthopaedic Hospital, Helsinki, Finland
4Division of Rheumatology, Department of Internal Medicine, Oulu University Hospital and Medical Research Center Oulu, Oulu, Finland
5Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
6Department of Medicine, Kuopio University Hospital, Kuopio, Finland
7Department of Public Health Solutions, Finnish Institute for Health and Welfare (THL), Helsinki, Finland
8Institute for Molecular Medicine Finland, FIMM, HiLIFE, University of Helsinki, Helsinki, Finland
9Department of Medicine, Jyväskylä Central Hospital, Jyväskylä, Finland
10FinnGen members are listed in the Supplementary material
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.8 MB)
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Language: English
Published: Informa, 2023
Publish Date: 2023-10-23


Objective: The aim of this study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in Finnish biobanks.

Method: We reviewed the electronic medical records of 500 Finnish biobank participants: 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA, and 250 age- and gender-matched controls. The patients were chosen from five different biobank hospitals in Finland. A rheumatologist reviewed the medical records to assess whether each patients’ diagnosis was correct. The diagnosis was compared with the diagnostic codes in the Finnish Care Register for Health Care (CRHC) and special reimbursement data of the Social Insurance Institution of Finland.

Results: The positive predictive value (PPV) of CRHC diagnosis of RA (for seropositive and seronegative RA combined) was 0.82. For patients with a special reimbursement for anti-rheumatic medications for RA, the PPV was 0.89. The PPV was higher in patients with more than one visit. For one, two, five, and 10 visits, the PPV was 0.82, 0.85, 0.89, and 0.90, respectively, and for patients who also had the special reimbursement, the PPV was 0.89, 0.91, 0.93, and 0.94 for one, two, five, and 10 visits, respectively. In patients positive for anti-citrullinated protein antibodies, the PPV was 0.98.

Conclusion: These results demonstrate that the validity of RA diagnoses in Finnish biobanks was good and can be further improved by including data on special reimbursement for medication, number of visits, and serological data.

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Series: Scandinavian journal of rheumatology
ISSN: 0300-9742
ISSN-E: 1502-7732
ISSN-L: 0300-9742
Volume: 52
Issue: 1
Pages: 1 - 9
DOI: 10.1080/03009742.2021.1967047
Type of Publication: A1 Journal article – refereed
Field of Science: 3121 General medicine, internal medicine and other clinical medicine
Funding: This work was supported by research grants from the FinnGen research project to JP, H-KH, and AP; the Finnish Foundation for Rheumatic Diseases to JP; Turunmaa Duodecim Society to JP; Finska Läkaresällskapet and Stockmanns Foundation to KKE; and the Academy of Finland [grant number 321356] to ASH.
Dataset Reference: Due to Finnish national data protection legislation, the register data used in this study cannot be shared without permission from the Health and Social Data Permit Authority of Finland.
Copyright information: © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License ( licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.