Using population register data for health services research – the Finnish experience

Abstract

Abstract The personal identification number was introduced in Finland in the mid-1960s. By 1970, it was universally used in administrative databases including population census, causes of death, cancer, hospital discharge, and health insurance registries. Early on data protection regulations recognised the use of registries and ID numbers for research and register linkages which allowed expanding the use of register data in population health and health services research. The possibility to analyse electronic health records (eHRs) linked to individual whole-population sociodemographic data has allowed the use of a wide range of study designs from cross-sectional to longitudinal studies and to various hierarchical designs. Some registers extend follow-up time up to over 50 years with detailed mapping of individual event histories. Data also allow detailed disentangling of individual and contextual factors, such as socioeconomics and comorbidities vs. provider characteristics. While some data items draw on administrative decisions or clinical discretion, such as granting insurance benefits or decisions on surgery, the research use of the data requires understanding of processes used to construct data items. The use of population registers in health services research is clearly cost-effective. However, the lack of a high-performance computing capacity and environment suitable for processing large sensitive data, as well as inadequate information on the use of primary health care and eHRs has limited efficient use of extensive and complex linkage schemes and the utilisation of machine learning. The Finnish register authorities have improved computing facilities for research use and the legislative reform on secondary use of health care data is opening eHRs for research use granting higher granularity in describing content and quality of care. These developments enable big-data methods to be an essential part of the future methodological toolbox for health service research.