Back to Journals » Clinical Epidemiology » Volume 10

Hydatidiform mole: validity of the registration in the Danish National Patient Registry, the Danish Cancer Registry, and the Danish Pathology Registry 1999–2009

Authors Lund H, Vyberg M, Eriksen HH, Grove A, Jensen AØ, Sunde L

Received 29 March 2018

Accepted for publication 31 May 2018

Published 18 September 2018 Volume 2018:10 Pages 1223—1231


Checked for plagiarism Yes

Review by Single anonymous peer review

Peer reviewer comments 3

Editor who approved publication: Professor Vera Ehrenstein

Helle Lund,1,2 Mogens Vyberg,1,2 Helle Højmark Eriksen,3 Anni Grove,1 Annette Østergaard Jensen,1 Lone Sunde4,5

1Institute of Pathology, Aalborg University Hospital, Aalborg, Denmark; 2Department of Clinical Medicine, Aalborg University, Aalborg, Denmark; 3Unit of Epidemiology and Biostatistics, Aalborg University Hospital, Aalborg, Denmark; 4Department of Clinical Genetics, Aarhus University Hospital, Aarhus, Denmark; 5Department of Biomedicine, Aarhus University, Aarhus, Denmark

Purpose: To examine the validity of registration of hydatidiform mole (HM) in the Danish National Patient Registry (NPR), the Danish Cancer Registry (DCR), and the Danish Pathology Registry (DPR).
Patients and methods: We selected women registered with a first-time HM code in NPR, DCR, and DPR from 1999 to 2009. We found most women registered in DPR. For a random sample of women registered in DPR, the coding was validated by comparing with the pathology report. Completeness and positive predictive value (PPV) of registration with an HM code in NPR and DCR were calculated using DPR as the reference. Details of women registered in NPR or DCR, but not in DPR, were scrutinized.
Results: In NPR and DPR, 1,520 women were identified in total; 1,057 (70%) were found in both registries, 65 (4%) only in NPR, and 398 (26%) only in DPR. In DCR and DPR, 1,498 women were identified in total; 1,174 (78%) in both registries, 47 (3%) only in DCR, and 277 (19%) only in DPR. For 149/150 randomly selected women registered with an HM code in DPR (99%), the pathology report was consistent with the diagnosis of HM. Completeness of NPR was 73% (95% CI: 70%–75%) and PPV was 94% (95% CI: 93%–95%). Completeness of DCR was 72% (95% CI: 69%–75%) in 1999–2003 and 90% (95% CI: 87%–92%) in 2004–2009. PPV of DCR was 96% (95% CI: 95%–97%) throughout the period.
Conclusion: Validation of registry data is important before using these. For research on the number of HMs in Denmark, DPR is the most valid data source. NPR and DCR appear to be equally valid before 2004. However, for research after 2004, DCR should be preferred rather than NPR.

Keywords: epidemiology, completeness, positive predictive value, complete hydatidiform mole, partial hydatidiform mole, agreement

Creative Commons License This work is published and licensed by Dove Medical Press Limited. The full terms of this license are available at and incorporate the Creative Commons Attribution - Non Commercial (unported, v3.0) License. By accessing the 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.

Download Article [PDF]  View Full Text [HTML][Machine readable]