Development of a measure of decision quality for implantable defibrillators.

Background: CMS reimbursement guidelines for implantable cardioverter-defibrillators (ICDs) include mandated shared decision making (SDM), but without any manner of assessing the quality of decisions made. We developed and tested a scale meant to assess patients' knowledge of and preferences specific to ICDs. Such a tool would assess these constructs in the clinical environment, targeting resources and support for patients considering a primary prevention ICD.

Methods: Development of the ICD decision quality (ICD-DQ) scale included (1) item creation, (2) content validation using surveys of patients (n = 23) and clinicians (n = 31), and (3) examination of validity and reliability using a survey of patients who previously received an ICD (n = 295, response rate = 72%).

Results: The final scale consists of 12 knowledge and 8 preference items. With respect to content validity, clinician and patient respondents agreed on the importance of 19 of 24 candidate knowledge items (79%), and 9 of 11 treatment preference items (81%). Knowledge items exhibited moderate internal validity (α = 0.62, 1 factor), strong test-retest reliability (mean % correct at first administration = 59%, 62% at follow-up, P > .1) and discriminant validity (59% correct for patients, 93% among cardiologists). Short versions of the ICD-DQ were developed for clinical settings, the scores from both of which correlated with the long version in this cohort (11-item (r = 0.90) and a 5-item (r = 0.75)).

Conclusions: The ICD-DQ fills a critical gap in measuring the quality of patients' ICD decisions. They may be used to evaluate the effectiveness of patient decision aids or the quality of SDM in clinical practice.