Conceptualizing and Prioritizing Clinical Trial Outcomes from the Perspectives of People with Parkinson's Disease Versus Health Care Professionals: a Concept Mapping Study

Background: Focusing clinical investigations on outcomes that are meaningful from an end-user perspective is central in clinical research, particularly in chronic disorders such as Parkinson's disease (PD). However, little is known about how end-users such as people with PD (PwPD) and health care professionals (HCPs) view and prioritize therapeutic outcomes.

Purpose: To compare the perspectives of PwPD and HCPs regarding prioritized areas for outcome measurement in clinical PD trials.

Methods: Concept mapping was used to identify prioritized outcomes (statements) through focus groups (n = 27; 12 PwPD, 12 HCPs, three researchers), statement sorting and importance rating (n = 38; 19 PwPD, 19 HCPs), followed by quantitative (multidimensional scaling, cluster analysis, procrustes analysis) and qualitative analysis.

Results: Sorting of 99 statements by PwPD and HCPs yielded 2D maps (PwPD/HCPs stress values, 0.31/0.21) with eight clusters per group. The correlation between raw sorting data of PwPD and HCPs was 0.80, and there was a significant concordance (m 12 = 0.53; P < 0.001; i.e., r = 0.68) between the spatial arrangements in their respective maps. Qualitatively, the maps from the two groups represented partially different perspectives. There were no significant differences between PwPD and HCP item importance ratings.

Conclusion: Although similarities dominated, there were differences in how the relationships between items were perceived by the two groups, emanating from different perspectives, i.e., the clinical biomedical ("disease") versus the lived experience ("illness"). This study illustrates the clinical importance of attention to the perspective of PwPD; taking this into account is likely to provide evidence from clinical investigations that are meaningful and interpretable for end-users.