Background: Patient decision aids (PtDAs) are tools designed to help people participate in decision making about health care options, providing information on the options and helping patients clarify and communicate their personal values and preferences. There is increasing recognition of the importance of addressing health literacy in PtDA development.

Objective and methods: As part of an update of the International Patient Decision Aid Standards, the aim of this study was to conduct a review to examine the extent to which PtDAs are designed to meet the needs of lower health literacy/socially disadvantaged populations.

We searched the reference list of the Cochrane reviews of randomised controlled trials (RCTs) of PtDAs (2014, 2017 and upcoming 2021 versions) and included RCTs that assessed the impact of PtDAs on people with lower health literacy or other socially disadvantaged groups (i.e. ≥50% participants from socially disadvantaged groups and/or subgroup analysis in socially disadvantaged group/s). Two researchers independently extracted data into a standardized form including PtDA development and evaluation details. We searched online repositories and emailed authors to access PtDAs to verify reading level and understandability and actionability using the Patient Education Materials Assessment tool.

Results: Twenty-five out of 213 RCTs of PtDAs met inclusion criteria for our study, illustrating that only 12% of studies specifically addressed the needs of lower health literacy or other socially disadvantaged groups. Reading age was calculated in 8/25 studies (33%), which is recommended in previous IPDAS guidelines. We accessed and independently assessed 11 PtDAs. None were written at 6^th grade level or below. Ten PtDAs met the recommended threshold for understandability, but only 5 met the recommended threshold for actionability. We also conducted a post-hoc subgroup meta-analysis and found that knowledge improvements after receiving a PtDA were greater in studies that reported using strategies to reduce cognitive demand in the PtDA development compared to studies that did not (Chi²=14.11, p=0.0002, I²=92.9%).

Conclusions: Greater attention to health literacy and socially disadvantaged populations is needed in the field of PtDAs to maximize equity in decision support.