Evaluation of an indirect record linkage method in an exemplary study on the risk of cancer and cancer mortality in type 2 diabetes patients treated with different antidiabetics

• Applicants: Professorin Dr. Iris Pigeot; Professor Dr. Wolfgang Rathmann
• Subject Area: Epidemiology and Medical Biometry/Statistics
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 316648086

Claims data of statutory health insurance providers are an important resource for epidemiological studies in health services and drug safety research. The benefit of these data stems from the large number of patients and the potential for long follow-up periods offering the opportunity to investigate both very rare adverse drug reactions and adverse drug reactions with long latency times. Important information about diseases such as tumor stage or cause of death are lacking since the data was collected for billing and not primarily for research purposes. Furthermore, the validity of tumor diagnoses in the data is unknown. A linkage of claims data with data from a cancer registry provides the missing information, thereby making an essential contribution to the investigation of the effects of carcinogenic substances. In this research proposal, an exemplary study of cancer risk and cancer mortality in type 2 diabetes patients treated with different antidiabetic therapies serves to evaluate to which extent easier data access can be facilitated using different methods of linking pseudonymized claims data to data from epidemiological cancer registries in Germany. First, an indirect record linkage will be performed using year of birth, sex, community code, and date/quarter of the tumor diagnosis. Second, the results will be evaluated by a well-established and exact, yet elaborate linkage procedure using so-called control numbers. As such a linkage requires a very stringent data protection concept and is very time-consuming, it is not feasible for every research question. Using the exemplary study, the differences in quality between the two linked datasets will be described and assessed. The overall objective of this project is to optimize the linkage procedures of both methods in order to give recommendations for the cost and time-efficient conduct of further studies with specific data protection requirements. Furthermore, recommendations will be given under which circumstances either one of the two linkage procedures will lead to valid findings. The results of the project will be disseminated to researchers using secondary data in Germany.

• DFG Programme: Research data and software (Scientific Library Services and Information Systems)
• Participating Institution: AOK Bremen/Bremerhaven; Epidemiologisches Krebsregister Niedersachsen; Registerstelle; OFFIS CARE GmbH; Gemeinsames Krebsregister der Länder Berlin, Brandenburg, Mecklenburg-Vorpommern, Sachsen-Anhalt und der Freistaaten Sachsen und Thüringen (GKR); Behörde für Wissenschaft, Forschung, Gleichstellung und Bezirke (BWFGB); Hamburgisches Krebsregister (HKR); hkk; Institut für Krebsepidemiologie e.V. an der Universität zu Lübeck ; (Krebsregister für Schleswig-Holstein); Universität Bremen; Institut für Informations-, Gesundheits- und Medizinrecht; Vertrauensstelle der pharmakoepidemiologischen Forschungsdatenbank; Vertrauensstelle des Krebsregisters; bei der Ärztekammer Schleswig-Holstein; Bayerisches Landesamt für Gesundheit und Lebensmittelsicherheit; Sachgebiet GE5; Zentrum für Krebsfrüherkennung und Krebsregistrierung