Use of Linked Nordic Registries for Population Studies in Hematologic Cancers: The Case of Multiple Myeloma

Abstract

Purpose

Linked health-care registries and high coverage in Nordic countries lend themselves well to epidemiologic research. Given its relatively high incidence in Western Europe, complexity in diagnosis, and challenges in registration, multiple myeloma (MM) was selected to compare registries in Denmark, Finland, and Sweden.

Patients and Methods

Data were obtained from four archetypal registries in each country (spanning January 2005–October 2018): National Patient Registry (NPR), Prescribed Drug Registry (PDR), Cancer Registry (CR), and Cause of Death Registry. Patients newly diagnosed with MM who received MM-specific treatment were included. PDR/NPR treatment records were used to assess incident NPR cases. The registration quality of MM-specific drugs in the PDR of each country was also evaluated.

Results

In Denmark, only 6% of patients in the NPR were not registered in the CR; in Sweden, it was 16.9%. No systematic differences were identified that could explain this discrepancy. In Denmark, lenalidomide and bortezomib were registered in the NPR with high coverage, but less expensive drugs typically given in combination with bortezomib were not covered in any of the registries. In Finland and Sweden, bortezomib records were not identified in the PDR, but some were in the NPR; other drugs had good coverage in the PDR.

Conclusions

The registries evaluated in this study can be used to identify the MM population; however, given the gaps in MM registration in the Finnish and Swedish CRs, Danish registries provide the most comprehensive datasets for research on treatment patterns for MM.

Plain Language Summary

National patient registries collect observational data on populations of patients and are often used for research. In this study, we investigated how complete the national patient registries were for Denmark, Finland and Sweden when recording the number of patients with multiple myeloma (MM; a type of bone marrow cancer) between 2005 and 2018. We also investigated the completeness in registration of given treatments during the study period in the national registries. Overall, the Danish national patient registries had the most comprehensive information on patients with MM. Registry data from Denmark could therefore be useful for conducting further research into the characteristics, treatment patterns, and outcomes of patients with MM.

Keywords:

• incidence
• prevalence
• real-world evidence

Abbreviations

ASCT, autologous stem cell transplantation; ATC, Anatomical Therapeutic Chemical; AvoHILMO, National Care Registry for Primary Healthcare Institutions; CDR, Cause of Death Registry; CR, Cancer Registry; DAGS, Danish Outpatient Grouping System; DMMR, Danish National Multiple Myeloma Registry; DRG, Diagnosis Related Groups; EMR, electronic medical record; HILMO, National Care Registry for Health Care Institutions; HUMAN, Health outcomes and Understanding of Myeloma: A multi-National study; ICD-10, International Classification of Diseases 10th Revision; ICPC-2, International Classification of Primary Care 2nd Edition; IPÖ, Individual Patient Overview; KVÅ, Koder ur Klassifikation av vårdåtgärder (classification of care measures); MM, multiple myeloma; NCSP, Nordic Classification of Surgical Procedures; NDMM, newly diagnosed multiple myeloma; NPR, National Patient Registry; OTC, over the counter; PDR, Prescribed Drug Registry; THL, Terveyden ja hyvinvoinnin laitos.

Data Sharing Statement

The datasets generated during and/or analyzed during the study are not publicly available but are available from the corresponding author on reasonable request.

Acknowledgments

The authors gratefully acknowledge the contribution of Anders Green, MD, DrMedSci, Institute of Applied Economics and Health Research and Odense University Hospital, Odense, Denmark, in providing scientific support and advice on access to, and management of data from, the Danish registries. Writing support was provided by Kate Bradford at Parexel, funded by Takeda Pharmaceuticals International AG.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis, and interpretation, or in all areas; took part in drafting, revising, or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

N Abildgaard has received research grants from Amgen, Bristol Myers Squibb, Celgene, Janssen, and Takeda; consulting fees from Bristol Myers Squibb, Celgene, Janssen, Novartis, and Takeda. J Freilich and Y Ma are employees of Parexel and received funding from Takeda for conducting study analyses. N Bent-Ennakhil and S Ørstavik are employees of Takeda. P Anttila has received consulting fees from Amgen, Bristol Myers Squibb, Celgene, GlaxoSmithKline, Janssen, Novartis, Sanofi, and Takeda; travel grants from AbbVie, Amgen, Bristol Myers Squibb, Celgene, Janssen, Mundipharma, Novartis, Roche, Sanofi Genzyme, and Teva. A Waage has received consulting fees from Janssen and Takeda. M Lassenius and I Toppila are employees of Medaffcon; Medaffcon received funding from Parexel for conducting study analyses. I Turesson has received consulting fees from Janssen and Takeda. M Hansson has received consulting fees from Janssen, Pfizer, Takeda, and Bristol Myers Squibb. The authors report no other conflicts of interest in this work.

Additional information

Funding

Study funded by Takeda Pharmaceuticals International AG.