Psychometric properties of the Danish SDM-Q-9 questionnaire for shared decision-making in patients with pelvic floor disorders and low back pain: item response theory modelling

The Danish SDM-Q-9 demonstrates strong overall performance, with the ability to differentiate between the distinct levels of the underlying construct of SDM. However, the high ceiling effect is a critical limitation. While the SDM-Q-9 could serve as a generic questionnaire across samples with varying demographic composition, further exploration of these findings is warranted, particularly across patient samples encompassing more diverse decisions, e.g. patients with life-threatening diseases.