Secondary data collection refers to collection of data already gathered for another purpose (e.g. electronic healthcare data, claims or prescription data). These can also be linked to non-medical data. The last two decades have witnessed the development of key data resources, expertise and methodology that have allowed use of such data for pharmacoepidemiology. The ENCePP Inventory of Data Sources contains key information on the databases that are registered in ENCePP. Section 4.6 of this Guide also describes existing research networks.
A comprehensive description of the main features and applications of frequently used databases for pharmacoepidemiology research in the United States and in Europe appears in the book Pharmacoepidemiology (B. Strom, S.E. Kimmel, S. Hennessy. 5th Edition, Wiley, 2012, Chapters 11 - 18). The limitations existing in using electronic healthcare databases should be acknowledged, as detailed in A review of uses of healthcare utilisation databases for epidemiologic research on therapeutics (J Clin Epidemiol 2005; 58: 23-337).
The primary purpose of the ISPE-endorsed Guidelines for Good Database Selection and use in Pharmacoepidemiology Research (Pharmacoepidemiol Drug Saf 2012;21:1-10) is to assist in the selection and use of data resources in pharmacoepidemiology by highlighting potential limitations and recommending tested procedures. This text mainly refers to databases of routinely collected healthcare information and does not include spontaneous report databases. It is a simple, well-structured guideline that will help investigators when selecting databases for their research and helps database custodians to describe their database in a useful manner. An entire section is dedicated to the use of multi-site studies. The entire document contains references to data quality and data processing/transformation issues and there are sections dedicated to quality and validation procedures. There are also separate sections on privacy and security.
The Working Group for the Survey and Utilisation of Secondary Data (AGENS) with representatives from the German Society for Social Medicine and Prevention (DGSPM) and the German Society for Epidemiology (DGEpi) developed a Good Practice in Secondary Data Analysis Version 2 aiming to establish a standard for planning, conducting and analysing studies on the basis of secondary data. It is also aimed to be used as the basis for contracts between data owners (so-called primary users) and secondary users. It is divided into 11 sections addressing, among other aspects, the study protocol, quality assurance and data protection.
The FDA’s Best Practices for Conducting and Reporting Pharmacoepidemiologic Safety Studies Using Electronic Health Care Data Sets provides criteria for best practice that apply to design, analysis, conduct and documentation. It emphasizes that investigators should understand potential limitations of electronic healthcare data systems, make provisions for their appropriate use and refer to validation studies of safety outcomes of interest in the proposed study and captured in the database.
General guidance for studies including those conducted with electronic healthcare databases can also be found in the ISPE GPP, in particular sections IV-B (Study conduct, Data collection). This guidance emphasises the paramount importance of patient data protection.
The International Society for Pharmacoeconomics and Outcome Research (ISPOR) established a task force to recommend good research practices for designing and analysing retrospective databases for comparative effectiveness research (CER). The Task Force has subsequently published three articles (Part I, Part II and Part III) that review methodological issues and possible solutions for CER studies based on secondary data analysis (see also section 10.1 on comparative effectiveness research). Many of the principles are applicable to studies with other objectives than CER, but aspects of pharmacoepidemiological studies based on secondary use of data, such as data quality, ethical issues, data ownership and privacy, are not covered.
Particular issues to be considered in the use of electronic healthcare data for pharmacoepidemiological research include the following:
An example of the hazards of using large linked databases is provided in Vaccine safety surveillance using large linked databases: opportunities, hazards and proposed guidelines (Expert Rev Vaccines 2003; 2(1):21-9).
Quality management is further addressed in section 7 of the Guide.
|10. Specific topics|
|Annex 1.||Guidance on conducting systematic revies and meta-analyses of completed comparative pharmacoepidemiological studies of safety outcomes|