Forty-two systematic reviews generated 23 items for assessing the risk of bias in values and preferences' studies

OBJECTIVES: In systematic reviews of studies of patients' values and preferences, the objective of the study was to summarize items and domains authors have identified when considering the risk of bias (RoB) associated with primary studies. STUDY DESIGN AND SETTING: We conducted a systematic survey of systematic reviews of patients' values and preference studies. Our search included three databases (MEDLINE, EMBASE, and PsycINFO) from their inception to August 2015. We conducted duplicate data extraction, focusing on items that authors used to address RoB in the primary studies included in their reviews and the associated underlying domains, and summarized criteria in descriptive tables. RESULTS: We identified 42 eligible systematic reviews that addressed 23 items relevant to RoB and grouped the items into 7 domains: appropriate administration of instrument; instrument choice; instrument-described health state presentation; choice of participants group; description, analysis, and presentation of methods and results; patient understanding; and subgroup analysis. CONCLUSION: The items and domains identified provide insight into issues of RoB in patients' values and preference studies and establish the basis for an instrument to assess RoB in such studies.