Development and psychometric properties of the general public's attitudes toward advance care directives scale in Portugal

Carlos Laranjeira; Maria Dos Anjos Dixe; Luís Gueifão; Lina Caetano; Rui Passadouro; Tiago Gabriel; Ana Querido

doi:10.4081/jphr.2021.1881

Development and psychometric properties of the general public's attitudes toward advance care directives scale in Portugal

J Public Health Res. 2021 Feb 23;10(1):1881. doi: 10.4081/jphr.2021.1881. eCollection 2021 Jan 14.

Authors

Carlos Laranjeira¹, Maria Dos Anjos Dixe², Luís Gueifão³, Lina Caetano⁴, Rui Passadouro⁵, Tiago Gabriel⁶, Ana Querido⁷

Affiliations

¹ School of Health Sciences of Polytechnic Institute of Leiria; Research in Education and Community Intervention (RECI), Piaget Institute; Center for Innovative Care and Health Technology (ciTechCare), Polytechnic of Leiria.
² School of Health Sciences of Polytechnic of Leiria; Center for Innovative Care and Health Technology (ciTechCare), Polytechnic of Leiria.
³ Intensive Care Unit, Leiria Hospital Center, Leiria.
⁴ Leiria Hospital Center, Leiria.
⁵ ACES do Pinhal Litoral, Leiria; Center for Innovative Care and Health Technology (ciTechCare), Polytechnic of Leiria.
⁶ ACES do Pinhal Litoral, Leiria.
⁷ School of Health Sciences of Polytechnic of Leiria; Center for Innovative Care and Health Technology (ciTechCare), Polytechnic of Leiria, Center for Research in Health and Information Systems (CINTESIS), NursID, University of Porto, Portugal.

Abstract

Background: To date, no instrument in Portugal has evaluated the attitudes of the population about advance care directives. This paper describes the development and testing of the General Public's Attitudes Toward Advance Care Directives (GPATACD) Scale. Design and Methods: Methodological study. The development of the instrument was based on a literature review, updated in 2018. Face and content validity were verified by an expert panel and piloted among six participants. Data were collected in an online survey of 1024 Portuguese adults. The obtained data were analyzed using Varimax rotation, while the reliability was evaluated by calculating Cronbach's alpha. Results: The scale achieves good Item-Content Validity Index (I-CVI) values, between 0.89 and 1.00, and scale-CVI values of 0.91. A principal component analysis generated four dimensions with 26 items as a final scale, with overall Cronbach's alpha of 0.848. Conclusions: The findings demonstrate that the scale is valid and reliable as a vehicle for assessment of the general public's attitudes toward advance care directives.

Keywords: Advance care directives; Portugal; instrument development; reliability; validity.

Grants and funding

Funding: This work was funded by Portuguese national funds provided by Fundação para a Ciência e Tecnologia (FCT) (UIDB/05704/2020 and UIDP/05704/2020). The funder had no role in the study design, data collection, analysis, and interpretation, presentation of results or decision to submit for publication.