Aalborg Universitet The Danish Myelodysplastic Syndromes Database: Patient Characteristics and Validity of Data Records Lauritsen, Tine Bichel; Nørgaard, Jan Maxwell; Grønbæk, Kirsten; Vallentin, Anders Pommer; Ahmad, Syed Azhar; Hannig, Louise Hur; Severinsen, Marianne Tang; Adelborg, Kasper; Østgård, Lene Sofie Granfeldt Published in: Clinical Epidemiology DOI (link to publication from Publisher): 10.2147/CLEP.S306857 Creative Commons License CC BY-NC 4.0 Publication date: 2021 Document Version Publisher's PDF, also known as Version of record Link to publication from Aalborg University Citation for published version (APA): Lauritsen, T. B., Nørgaard, J. M., Grønbæk, K., Vallentin, A. P., Ahmad, S. A., Hannig, L. H., Severinsen, M. T., Adelborg, K., & Østgård, L. S. G. (2021). The Danish Myelodysplastic Syndromes Database: Patient Characteristics and Validity of Data Records. Clinical Epidemiology, 13, 439-451. https://doi.org/10.2147/CLEP.S306857 General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights. ? Users may download and print one copy of any publication from the public portal for the purpose of private study or research. ? You may not further distribute the material or use it for any profit-making activity or commercial gain ? You may freely distribute the URL identifying the publication in the public portal ? Clinical Epidemiology Dovepress open access to scientific and medical research Open Access Full Text Article ORIGINAL RESEARCH The Danish Myelodysplastic Syndromes Database: Patient Characteristics and Validity of Data Records Tine Bichel Lauritsen 1 Background: The Danish Myelodysplastic Syndromes Database (DMDSD) comprises Jan Maxwell Nørgaard 1 nearly all patients diagnosed with myelodysplastic syndromes (MDS) in Denmark since Kirsten Grønbæk2–4 2010. The DMDSD has not yet been used for epidemiological research and the quality of Anders Pommer Vallentin5 registered variables remains to be investigated. Syed Azhar Ahmad6 Objective: To describe characteristics of the patients registered in the DMDSD and to Louise Hur Hannig7 calculate predictive values and the proportion of missing values of registered data records. Marianne Tang Severinsen 8,9 Methods: We performed a nationwide cross-sectional validation study of recorded disease Kasper Adelborg10,11 and treatment data on MDS patients during 2010–2019. Patient characteristics and the Lene Sofie Granfeldt Østgård11,12 proportion of missing values were tabulated. A random sample of 12% was drawn to For personal use only. calculate predictive values with 95% confidence intervals (CIs) of 48 variables using 1Department of Hematology, Aarhus University Hospital, Aarhus, Denmark; information from medical records as a reference standard. 2 Department of Hematology, Results: Overall, 2284 patients were identified (median age: 76 years, men 62%). Of these, Rigshospitalet, Copenhagen, Denmark; 3Biotech Research and Innovation Centre 10% had therapy-related MDS, and 6% had an antecedent hematological disease. (BRIC), University of Copenhagen, Hemoglobin level was less than 6.2 mmol/L for 59% of patients. Within the first two 4 Copenhagen, Denmark; Novo Nordisk years of treatment, 59% received transfusions, 35% received erythropoiesis-stimulating Foundation Center for Stem Cell Biology (DanStem), Faculty of Health Sciences, agents, and 15% were treated with a hypomethylating agent. For the majority of variables University of Copenhagen, Copenhagen, (around 80%), there were no missing data. A total of 260 medical records were available for 5 Denmark; Zealand University Hospital, validation. The positive predictive value of the MDS diagnosis was 92% (95% CI: 88–95). Roskilde, Denmark; 6Department of Hematology, Herlev Hospital, Herlev, Predictive values ranged from 64% to 100% and exceeded 90% for 36 out of 48 variables. Denmark; 7Department of Hematology, Stratification by year of diagnosis suggested that the positive predictive value of the MDS Clinical Epidemiology downloaded from https://www.dovepress.com/ by 87.53.131.88 on 16-Jun-2021 Vejle Hospital, Vejle, Denmark; 8Department of Hematology, Clinical diagnosis improved from 88% before 2015 to 95% after. Cancer Research Center, Aalborg Conclusion: In this study, there was a high accuracy of recorded data and a low proportion University Hospital, Aalborg, Denmark; of missing data. Thus, the DMDSD serves as a valuable data source for future epidemiolo­ 9Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; gical studies on MDS. 10Department of Clinical Biochemistry, Keywords: myelodysplastic syndromes, cohort, validation, accuracy, database Aarhus University Hospital, Aarhus, Denmark; 11Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark; 12Department of Hematology, Odense University Hospital, Introduction Odense, Denmark Myelodysplastic syndromes (MDS) encompasses a heterogeneous group of myeloid neoplasms characterized by inefficient hematopoiesis, morphologic dysplasia, and vari­ able degrees of cytopenias.1,2 MDS can be indolent or rapidly progressive, and may transform into secondary acute myeloid leukemia (sAML).1,2 The annual age-adjusted Correspondence: Tine Bichel Lauritsen Department of Hematology, Aarhus incidence is approximately 4 per 100,000 persons, increasing markedly with advancing University Hospital, Palle Juul-Jensens age.3–5 Despite improvements in treatment and increasingly use of allogeneic bone Boulevard 99, Aarhus N, 8200 5 Email [email protected] marrow transplantation (allo-HSCT), the five-year overall survival remains around 30%. Clinical Epidemiology 2021:13 439–451 439 Received: 22 February 2021 © 2021 Lauritsen et al. This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at https://www.dovepress.com/terms. Accepted: 7 April 2021 php and incorporate the Creative Commons Attribution – Non Commercial (unported, v3.0) License (http://creativecommons.org/licenses/by-nc/3.0/). By accessing the Published: 14 June 2021 work you hereby accept the Terms. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. For permission for commercial use of this work, please see paragraphs 4.2 and 5 of our Terms (https://www.dovepress.com/terms.php). Powered by TCPDF (www.tcpdf.org) Lauritsen et al Dovepress Denmark is known worldwide for its many high quality Data are submitted to the DMDSD through an online population-based health-care registries.6 The Danish registration system. Up to five standardized registration Myelodysplastic Syndromes Database (DMDSD) was forms are used to collect data for the DMDSD (Table launched in 2010 as a nationwide population-based data­ 1). The first form is completed at diagnosis. The second base, currently covering at least 98% of all Danish MDS and third forms are completed two and five years after patients.7 It contains detailed clinical data on MDS sub­ diagnosis or earlier in case of progression to sAML, death, types, comorbidity, laboratory records, cytogenetic altera­ or termination of outpatient follow-up. A follow-up form tions, treatment and progression to acute myeloid leukemia is completed at death or termination of outpatient follow- (sAML). Through linkage to the extensive network of up. The result of the cytogenetic evaluation is currently Danish health-care registries, the DMDSD holds several reported according to the Revised International Prognostic epidemiological research possibilities. The use of data may Scoring System (IPSS-R) by a clinical cytogeneticist at add to the understanding of the epidemiology of MDS, a separate registration form at diagnosis. Prior cytogenetic including time trends in incidence and survival, clinical results reported according to the International Prognostic course, and effectiveness and safety of different treatment Scoring System (IPSS) were revised and updated accord­ modalities. ing to IPSS-R by clinical cytogeneticists in 2020. IPSS-R Given that validation of a data source is a prerequisite data are, however, currently not available to researchers, prior to its use in epidemiological research, the objective and therefore they are not validated in this study, but IPSS of this study was to describe patient characteristics, the characteristics are shown in Table 2. proportion of missing values, and the validity of data Two Danish health-care registries are of central impor­ records in the DMDSD. tance to the DMDSD. The Civil Registration System pro­ vides data about vital status, date of death, and residential Methods area.10 The Danish National Patient Registry (DNPR) pro­ vides data on primary and secondary discharge diagnoses For personal use only. Setting (eg MDS ICD-10 codes) from all Danish hospitals since The Danish health-care system is universal and tax- 1977.11 Complete and valid linkage between these regis­ supported, providing free of charge and equal access to tries and the DMDSD is done via the unique central primary and hospital care for all Danish citizens.6 Patients personal registry number assigned to all Danish citizens.10 with MDS are treated with chemotherapy at six specialized To ensure that the DMDSD captures all newly diag­ hematological departments in Denmark and four