Patient reported outcome measures in rare diseases: a narrative review.

Patient input throughout the development of PROMs including qualitative research is essential to ensure that outcomes that matter to people living with rare disease are appropriately captured. Given the large number of rare diseases, small numbers of patients living with each condition and the cost of instrument development, creative and pragmatic solutions to PROM development and use may be necessary. Solutions include qualitative interviews, modern psychometrics and resources such as item banking and computer adaptive testing. Use of PROMs in rare disease research and clinical practice offers the potential to improve patient care and clinical outcomes.