OBJECTIVES: Although global patient-reported outcome (PRO) scales are frequently included in clinical trials as ‘anchors’ from which to evaluate the psychometric measurement properties and estimate meaningful changes on multi-item PRO questionnaires, the data from these scales are rarely examined as outcomes in and of themselves. Indeed researchers have long been warned about a lack of precision and, by extension, content validity in global PRO scales. But such scales are inherently appealing for use in settings where data is collected frequently and/or on digital devices with small screens (e.g. smart watches). We conducted a review of existing global PROs which have been included as evidence of treatment outcomes in drug development to evaluate their suitability for future use.

METHODS: A review of global PRO scales in US and EU product labels (US FDA prescribing information; EMA Summary of Product Characteristics) from 2009 to April 2021 was completed in PROLabels.

RESULTS: Seventeen global PRO scales (including 2 composites) supported outcomes across 22 product labels, 13 in US; 9 in EU. These labels span over 10 therapeutic areas (rare diseases, n=5; dermatology, rheumatology, sleep disorders, n=3 each; neurology, musculoskeletal, other, n=2 each; psychology, oncology, pain, n=1 each). The majority (n=14) of the scales measured multidimensional latent constructs (e.g. overall condition, overall status, treatment success, severity of symptoms); only three assessed simple constructs (physical well-being, aesthetic appearance, pain control method) . The evidence supporting the use of the scales as well-defined and reliable outcomes was examined in regulatory reviews and the literature, and was variable.

CONCLUSIONS: Global PRO scales have been approved in product labelling in the US and EU, in their own right, to support treatment outcome information. Further information is needed on how outcome data generated from global PRO scales compares to multi-item scales measuring the same concepts.