Protocol for a systematic review of preference-based instruments for measuring care-related outcomes and their suitability for the palliative care setting.

Introduction: Despite informal caregivers' integral role in supporting people affected by disease or disability, economic evaluations often ignore the costs and benefits experienced by this group, especially in the palliative setting. The purpose of this systematic review is to identify preference-based instruments for measuring care-related outcomes and provide guidance on the selection of instrument in palliative care economic evaluations. Methods and analysis: A comprehensive search of the literature will be conducted from database inception (ASSIA; CINAHL; Cochrane library including DARE, NHS EED, HTA; Econlit; Embase; PsychINFO; PubMed). Published peer-reviewed, English-language articles reporting preference-based instruments for measuring care-related outcomes in any clinical area will be included. One researcher will complete the searches and screen the results for potentially eligible studies. A randomly selected subset of 10% citations will be independently screened by two researchers. Any disagreement will be resolved by consensus among the research team. Subsequently, a supplementary search will identify studies detailing the development, valuation, validation and application of the identified instruments. The degree of suitability of the instruments for palliative economic evaluations will be assessed using criteria in the International Society for Quality of Life Research minimum standards for patient-reported outcome measures, the checklist for reporting valuation studies of multiattribute utility-based instruments and information on the development of the instrument in the palliative setting. A narrative summary of the included studies and instruments will be provided; similarities and differences will be described and possible reasons for variations explored. Recommendations for practice on selection of instruments in palliative care economic analyses will be provided. Ethics and dissemination: This is a planned systematic review of published literature. Therefore, ethics approval to conduct this research is not required. Findings will be presented at leading palliative care and health economic conferences and published in a peer-reviewed journal. Trial registration number: CRD42016034188