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534 – Contributed Poster Presentations: Section on Statistics in Epidemiology

Deriving and Validating New "Outcome" Variables in Patient Reported Epidemiological Data

at Collaborative for Research on Outcomes and -Metrics

Patient reported epidemiological data are becoming more widely available for the application of data scientific methodologies and other investigations. One new such dataset, the Fox Insight project, was launched in 2017 by the Michael J. Fox Foundation to encourage researchers to engage in the study of Parkinson's disease. The Fox Insight (FI) dataset will be released for public access late in 2018, and while it is longitudinal in nature, and while dedicated statistics and psychometrics cores have supported the scientific advisory committee in their considerations of which variables to collect, diseases like Parkinson's do not have unambiguous states (e.g., "mild" vs. "severe") or changes (e.g., "stable" vs. "worse"). Assessing these states can be complicated when there are medical comorbidities that may contribute to, compound, or be conflated with the symptoms of the disease of interest (e.g., cerebrovascular disease; muscle weaknesses due to stroke or aging; depression). This paper describes the development and proposed validation of two new variables in the FI data set that are intended for use as "outcomes", which would be available for interested researchers who download the FI data when it becomes publicly available. One represents "cognitive change" and the other represents the "off" syndrome of Parkinson's where symptoms suddenly become unresponsive to medication (that works otherwise) for short periods of time. We discuss how new outcomes like these can be developed from patient reported epidemiologic data like the FI set using theory, and validated using international consensus criteria (COSMIN). These results are useful for planning analyses of the FI dataset, but also may support future designs for similar patient reported epidemiological data sets, so that they will be designed to include outcome variables or variables that can be used to demonstrate alignment of derived outcomes with the COSMIN validity criteria.