Linkage of the Canadian Study of Health and Aging to Provincial Administrative Health Care Databases in Nova Scotia

Abstract

The Canadian Study of Health and Aging (CSHA) was a cohort study that included 528 Nova Scotian community-dwelling participants. Linkage of CSHA and provincial Medical Services Insurance (MSI) data enabled examination of health care utilization in this subsample. This article discusses methodological and ethical issues of database linkage and explores variation in the use of health services by demographic variables and health status. Utilization over 24 months following baseline was extracted from MSI's physician claims, hospital discharge abstracts, and Pharmacare claims databases. Twenty-nine subjects refused consent for access to their MSI file; health card numbers for three others could not be retrieved. A significant difference in healthcare use by age and self-rated health was revealed. Linkage of population-based data with provincial administrative health care databases has the potential to guide health care planning and resource allocation. This process must include steps to ensure protection of confidentiality. Standard practices for linkage consent and routine follow-up should be adopted. The Canadian Study of Health and Aging (CSHA) began in 1991-92 to explore dementia, frailty, and adverse health outcomes (Canadian Study of Health and Aging Working Group, 1994). The original CSHA proposal included linkage to provincial administrative health care databases by the individual CSHA study centers to enhance information on health care utilization and outcomes of study participants. In Nova Scotia, the Medical Services Insurance (MSI) administration, which drew the sampling frame for the original CSHA, did not retain the list of corresponding health card numbers. Furthermore, consent for this access was not asked of participants at the time of the first interview. The objectives of this study reported here were to examine the feasibility and ethical considerations of linking data from the CSHA to MSI utilization data, and to explore variation in health services use by demographic and health status characteristics in the Nova Scotia community cohort.