Developing an Instrument to Assess the Readiness for Advance Care Planning.

Context: In recent times, advance care planning for patients' end-of-life care preferences has attracted much attention worldwide.

Objectives: To develop the Readiness for Advance Care Planning (RACP) Scale.

Methods: Participants included 624 Japanese citizens who were registered with a web-based survey company as of February 2019. Items regarding the process of advance care planning (ACP) were developed based on a literature review and expert panel discussions. The expert panel included nine experts and practitioners in the field of end-of-life care. Construct validity, concurrent validity, internal consistency, and test-retest reliability were evaluated.

Results: Initially, 37 items were collected. Examination of the floor effect, item-total, good-poor analysis, and exploratory factor analysis yielded a five-factor model with 28 items. The goodness of fit of the model was GFI = 0.80, CFI = 0.91, and RMSEA = 0.08. The concurrent validity was statistically significant (rs = 0.26-0.45, ps < 0.001). Cronbach's alpha for the overall scale was 0.95. The corresponding values for the subscales ranged from 0.90 to 0.97. The intraclass correlation coefficients indicating test-retest reliability was 0.66 (P < 0.001) for the total scale and ranged from 0.52-0.65 for the five subscales.

Conclusions: The validity and reliability of the scale were generally acceptable. The RACP is an appropriate instrument to evaluate the level of readiness for ACP behaviors among people of various generations at every health stage. More studies are needed to examine the clinical utility of the RACP, both nationally and internationally.