Registrations of Patients with Renal Cell Carcinoma in the Nationwide Danish Renal Cancer Database versus the Danish Cancer Registry: Data Quality, Completeness and Survival (DaRenCa Study-3)

Bolette Danckert; Trine Allerslev Horsbøl; Ole Andersen; Susanne Oksbjerg Dalton; Jane Christensen; Margit Rasted; Astrid Petersen; Mette Nørgaard; Nessn Azawi; Lars Lund; Frede Donskov

doi:10.2147/CLEP.S258755

Registrations of Patients with Renal Cell Carcinoma in the Nationwide Danish Renal Cancer Database versus the Danish Cancer Registry: Data Quality, Completeness and Survival (DaRenCa Study-3)

Clin Epidemiol. 2020 Jul 27:12:807-814. doi: 10.2147/CLEP.S258755. eCollection 2020.

Authors

Affiliations

¹ Director´s Office, Danish Cancer Society Research Center, Copenhagen, Denmark.
² Survivorship and Inequality in Cancer, Danish Cancer Society Research Center, Copenhagen, Denmark.
³ Department of Clinical Oncology & Palliative Care, Zealand University Hospital, Næstved, Denmark.
⁴ Statistics and Data Analysis, Danish Cancer Society Research Center, Copenhagen, Denmark.
⁵ Danish Health Data Authority, Copenhagen, Denmark.
⁶ Department of Pathology, Aalborg University Hospital, Aalborg, Denmark.
⁷ Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus, Denmark.
⁸ Department of Urology, Zealand University Hospital, Roskilde, Denmark.
⁹ Department of Urology and Department of Clinical Research, University of Southern Denmark, Odense, Denmark.
¹⁰ Department of Oncology, Aarhus University Hospital, Aarhus, Denmark.

Abstract

Background: The Danish multidisciplinary renal cancer group (DaRenCa) established the nationwide database DaRenCaData in 2010. The Danish Cancer Registry (DCR) has been considered the golden standard. In contrast to DCR, DaRenCaData required the diagnosis to be histologically or cytologically verified. DaRenCaData and DCR have not previously been compared.

Patients and methods: We included patients with renal cell carcinoma registered in DaRenCaData and/or DCR from August 1st 2010 to December 31st 2015. We computed completeness and positive predictive value (PPV) of a diagnosis in DaRenCaData compared with DCR, 1-year, 3-year and 5-year mortality rate ratios, and relative survival.

Results: We identified 4890 patients in the two registries. Of these, 4326 were registered in DaRenCaData and 4714 in DCR. Completeness of DaRenCaData was 88% [95% CI, 87-89%] and increased during the period from 82% to 94%. The PPV was 96% [95% CI, 95-97%]. A total of 4150 patients (85%) were found in both registries, 4% (176 patients) in DaRenCaData only, and 12% (564 patients) in DCR only. The relative survival was higher for patients in DaRenCaData vs DCR; the 1-year and 5-year relative survival was 85% vs 81% and 65% vs 59%, respectively. Compared with patients registered in both registries, the mortality rates were higher in patients registered in DaRenCaData only (1-year hazard ratio (HR)=2.84 [95% CI, 2.20-3.68]) or DCR only (1-year HR=4.29 [95% CI, 3.72-4.93]). Observed in both registries, survival improved over time with a 7% yearly reduction in death based on estimations of 1-year mortality rate ratios.

Conclusion: DaRenCaData had high and increasing completeness and high PPV, establishing it as a high-quality research database. Observed in both registries, renal cell carcinoma mortality declined over time; patients only registered in DCR or DaRenCaData had poorer outcomes. This study points to the importance of assessing the inclusion criteria when interpreting registry-based studies.

Keywords: assessment of database; kidney cancer; national registries; survival.

Grants and funding

Research support: This study was supported by a grant from the Danish Cancer Society (R94-A6063-B271). FD received support from the Health Research Foundation of Central Denmark Region.