Is quality of life a suitable measure of patient decision aid effectiveness? Sub-analysis of a Cochrane systematic review.

Purpose: Patient decision-aids (PtDAs) help patients make informed treatment decisions incorporating their values. Health-related quality of life (HRQOL) is sometimes an outcome of PtDA effectiveness trials, but its suitability for this purpose is unclear. We sought to provide insights into this question by critically appraising how randomized controlled trials (RCTs) evaluating PtDA effectiveness measure and report HRQOL.

Methods: We conducted a sub-analysis of RCTs included in the 2017 Cochrane review of PtDAs. Trials assessing HRQOL at baseline and post-PtDA, and comparing PtDA with comparison groups were included. Two reviewers independently extracted data and assessed study quality. Analysis was descriptive.

Results: Of 105 RCTs, 11 were eligible for inclusion. Patients randomized to PtDAs did not report better HRQOL than those randomized to usual care. While all 11 RCTs adequately described baseline sample characteristics and reported HRQOL results for study groups, few stated a priori HRQOL expectations or hypotheses (36%); made a link between HRQOL and the decision (18%); provided a rationale or justification for HRQOL assessment (18%); provided reason for choice of HRQOL assessment time-points (9%); or adjusted p-values for multiple HRQOL domains and time-points (0%).

Discussion: PtDAs did not conclusively impact HRQOL. If this holds generally, then HRQOL is an uninformative endpoint for PtDA effectiveness trials. When planning trials of PtDAs, investigators considering HRQOL endpoints should consider whether and why their PtDA is likely to affect HRQOL in their context, and if so, which specific aspect(s) of HRQOL and at which time-point(s), and ensure HRQOL is assessed accordingly.