{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T13:03:46Z","timestamp":1761224626342,"version":"build-2065373602"},"reference-count":27,"publisher":"Danish Medical Association","issue":"10","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Dan Med J"],"abstract":"<jats:p>INTRODUCTION. Graves\u2019 disease (GD) is the leading cause of hyperthyroidism in women of fertile age. Register-based studies rely on diagnostic codes; this study examined the validity of diagnosed thyrotoxicosis among women of fertile age in the Danish National Hospital Register (DNHR).\n\nMETHODS. All women in the North Denmark Region aged 18-45 years with a diagnosis of thyrotoxicosis (Tenth International Classification of Diseases: E05.0-05.9) in the DNHR from 2017-2018 were identified and medical records reviewed.\n\nRESULTS. Among 263 women included, thyrotoxicosis was confirmed in 249 cases with a positive predictive value (PPV) of 94.7% (95% confidence interval (CI): 91.2-97.1%) for the diagnostic group (E05.0-05.9). Autoimmune hypothyroidism was the leading cause of misclassification. GD was the aetiology in 150 women, resulting in a PPV for GD of 57.0% (95% CI: 50.8-63.1%) in the diagnostic group (E05.0-05.9), increasing to 83.6% (95% CI: 76.4-89.3%) when restricted to women who were prescribed an antithyroid drug (ATD). The PPV for GD was highest when the specific diagnosis (DE05.0) was considered (PPV 91.1% (95% CI: 84.7-95.5%); however, 42 women with GD (28.0%) were first given a diagnosis of unspecified thyrotoxicosis (E05.9).\n\nCONCLUSIONS. The validity of thyrotoxicosis identified in the DNHR among women of fertile age was high. Results emphasise the importance of how subtypes of thyrotoxicosis are defined and show that the combined use of diagnoses and prescriptions of ATD is warranted to define GD.\n\nFUNDING. Novo Nordisk Foundation (grant no: NNF20OC0059465).\n\nTRIAL REGISTRATION. Not relevant.<\/jats:p>","DOI":"10.61409\/a04250296","type":"journal-article","created":{"date-parts":[[2025,10,8]],"date-time":"2025-10-08T06:47:32Z","timestamp":1759906052000},"page":"1-8","source":"Crossref","is-referenced-by-count":0,"title":["Validity of a thyrotoxicosis diagnosis code among women of fertile age"],"prefix":"10.61409","author":[{"given":"Nanna Maria Uldall","family":"Torp","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Signe","family":"Kirkegaard","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Karoline","family":"Schack","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Stine Linding","family":"Andersen","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"40208","published-online":{"date-parts":[[2025]]},"reference":[{"issue":"3","key":"ref0","doi-asserted-by":"publisher","first-page":"158","DOI":"10.1038\/s41574-021-00604-z","article-title":"Assessment and treatment of thyroid disorders in pregnancy and the postpartum period","volume":"18","author":"SY","year":"2022","unstructured":"Lee SY, Pearce EN. 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J Clin Endocrinol Metab. 2023;109(1):e370-e378.","DOI":"10.1210\/clinem\/dgad410"},{"key":"ref8","doi-asserted-by":"publisher","unstructured":"https:\/\/doi.org\/10.1210\/clinem\/dgad410","DOI":"10.1210\/clinem\/dgad410"},{"key":"ref9","doi-asserted-by":"publisher","unstructured":"Kildemoes HW, S\u00f8rensen HT, Hallas J. The Danish National Prescription Registry. Scand J Public Health. 2011;39(7 suppl):38-41.","DOI":"10.1177\/1403494810394717"},{"key":"ref10","doi-asserted-by":"publisher","unstructured":"https:\/\/doi.org\/10.1177\/1403494810394717","DOI":"10.1177\/1403494810394717"},{"key":"ref11","unstructured":"Andersen TF, Madsen M, J\u00f8rgensen J, et al. The Danish National Hospital Register: a valuable source of data for modern health sciences. Dan Med Bull. 1999;46(3):263-268"},{"key":"ref12","doi-asserted-by":"publisher","unstructured":"Andersen SL, Olsen J, Carl\u00e9 A, Laurberg P. Hyperthyroidism incidence fluctuates widely in and around pregnancy and is at variance with some other autoimmune diseases: a Danish population-based study. J Clin Endocrinol Metab. 2015;100(3):1164-1171. https:\/\/doi.org\/10.1210\/jc.2014-3588","DOI":"10.1210\/jc.2014-3588"},{"key":"ref13","doi-asserted-by":"publisher","unstructured":"Kahaly GJ, Bartalena L, Heged\u00fcs L, et al. 2018 European Thyroid Association guideline for the management of Graves' hyperthyroidism. Eur Thyroid J. 2018;7(4):167-186. https:\/\/doi.org\/10.1159\/000490384","DOI":"10.1159\/000490384"},{"key":"ref14","doi-asserted-by":"publisher","unstructured":"Ross DS, Burch HB, Cooper DS, et al. 2016 American Thyroid Association guidelines for diagnosis and management of hyperthyroidism and other causes of thyrotoxicosis. Thyroid. 2016;26(10):1343-1421. https:\/\/doi.org\/10.1089\/thy.2016.0229","DOI":"10.1089\/thy.2016.0229"},{"issue":"2","key":"ref15","doi-asserted-by":"publisher","first-page":"377","DOI":"10.1016\/j.jbi.2008.08.010","article-title":"Research electronic data capture (REDCap) - a metadata-driven methodology and workflow process for providing translational research informatics support","volume":"42","author":"Harris","year":"2009","unstructured":"Harris PA, Taylor R, Thielke R, et al. Research electronic data capture (REDCap) - a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377-381.","journal-title":"J Biomed Inform"},{"key":"ref16","doi-asserted-by":"publisher","unstructured":"https:\/\/doi.org\/10.1016\/j.jbi.2008.08.010","DOI":"10.1016\/j.jbi.2008.08.010"},{"key":"ref17","doi-asserted-by":"publisher","unstructured":"Harris PA, Taylor R, Minor BL, et al. The REDCap consortium: building an international community of software platform partners. J Biomed Inform. 2019;95:103208. https:\/\/doi.org\/10.1016\/j.jbi.2019.103208","DOI":"10.1016\/j.jbi.2019.103208"},{"key":"ref18","doi-asserted-by":"publisher","unstructured":"Vestergaard P, Mosekilde L. Fractures in patients with hyperthyroidism and hypothyroidism: a nationwide follow-up study in 16,249 patients. Thyroid. 2002;12(5):411-419. https:\/\/doi.org\/10.1089\/105072502760043503","DOI":"10.1089\/105072502760043503"},{"key":"ref19","unstructured":"Kjellerup CR, Thomsen MJ, Torp NMU, et al. Characteristics of patients with subacute thyroiditis. Dan Med J. 2023;70(11):A05230318"},{"key":"ref20","doi-asserted-by":"publisher","unstructured":"Klit F\u00d8, Dal J, Andersen SL, et al. Incidence of Graves' disease with validation and completeness of the diagnosis for registry extracts in the Danish National Patient Register. Clin Epidemiol. 2024;16:699-705. https:\/\/doi.org\/10.2147\/CLEP.S484335","DOI":"10.2147\/CLEP.S484335"},{"key":"ref21","doi-asserted-by":"publisher","unstructured":"Carl\u00e9 A, Pedersen IB, Perrild H, et al. High age predicts low referral of hyperthyroid patients to specialized hospital departments: evidence for referral bias. Thyroid. 2013;23(12):1518-1524. https:\/\/doi.org\/10.1089\/thy.2013.0074","DOI":"10.1089\/thy.2013.0074"},{"key":"ref22","doi-asserted-by":"publisher","unstructured":"Carle A, Laurberg P, Pedersen IB, et al. Mainly the younger hypothyroid patients are referred to hospital - evidence for referral bias. J Clin Epidemiol. 2009;62(4):446-451. https:\/\/doi.org\/10.1016\/j.jclinepi.2008.06.016","DOI":"10.1016\/j.jclinepi.2008.06.016"},{"key":"ref23","unstructured":"Dansk Endokrinologisk Selskab. Thyrotoxicose. Dansk Endokrinologisk Selskab, 2024. https:\/\/endocrinology.dk\/nbv\/thyroideasygdomme\/thyrotoksikose\/ (Apr 2025)"},{"issue":"1","key":"ref24","doi-asserted-by":"publisher","first-page":"8777","DOI":"10.1038\/s41598-024-59636-w","article-title":"Diagnoses of obstetric and postpartum thyroid disease: a Danish validation study","volume":"14","author":"Houm\u00f8ller","year":"2024","unstructured":"Houm\u00f8ller AM, Gerlif K, Torp NMU, Andersen SL. Diagnoses of obstetric and postpartum thyroid disease: a Danish validation study. Sci Rep. 2024;14(1):8777 .","journal-title":"Sci Rep"},{"key":"ref25","doi-asserted-by":"publisher","unstructured":"https:\/\/doi.org\/10.1038\/s41598-024-59636-w","DOI":"10.1038\/s41598-024-59636-w"},{"key":"ref26","doi-asserted-by":"publisher","unstructured":"Alexander EK, Pearce EN, Brent GA, et al. 2017 guidelines of the American Thyroid Association for the diagnosis and management of thyroid disease during pregnancy and the postpartum. Thyroid. 2017;27(3):315-389. https:\/\/doi.org\/10.1089\/thy.2016.0457","DOI":"10.1089\/thy.2016.0457"}],"container-title":["Danish Medical Journal"],"original-title":[],"deposited":{"date-parts":[[2025,10,23]],"date-time":"2025-10-23T12:39:28Z","timestamp":1761223168000},"score":1,"resource":{"primary":{"URL":"https:\/\/ugeskriftet.dk\/dmj\/A04250296"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025]]},"references-count":27,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2025]]}},"URL":"https:\/\/doi.org\/10.61409\/a04250296","relation":{},"ISSN":["2245-1919"],"issn-type":[{"type":"electronic","value":"2245-1919"}],"subject":[],"published":{"date-parts":[[2025]]}}}