Protocol for the development and validation of a measure of persistent psychological and emotional distress in cardiac patients: the Cardiac Distress Inventory

INTRODUCTION: Distress is experienced by the majority of cardiac patients, yet no cardiac-specific measure of distress exists. The aim of this project is to develop and validate the Cardiac Distress Inventory (CDI). Using the CDI, health professionals will be able to identify key clusters of psychological, emotional and social concern to address with patients, postcardiac event. METHODS AND ANALYSIS: An item pool will be generated through: identification of items by a multidisciplinary group of clinician researchers; review of generic and condition-specific distress measures; focus group testing with cardiac rehabilitation professionals; feedback from patients. The COSMIN (COnsensus-based Standards for the selection of health Measurement INstruments) criteria will be used to inform the development of the methodology for determining the CDI’s psychometric properties. The item pool will be tested with 400 cardiac patients and responses subjected to exploratory factor analysis, Rasch analysis, construct validity testing and latent class analysis. Receiver operating characteristic analysis will be used to identify the optimal CDI cut-off score for distinguishing whether a person experiences clinically significant distress. ETHICS AND DISSEMINATION: Approved by the Monash Health Human Research Ethics Committee (approval number—RES-19-0000631L-559790). The CDI will be made available to clinicians and researchers without charge. The CDI will be translated for use internationally. Study findings will be shared with cardiac patient support groups; academic and medical communities via publications and presentations; in the training of cardiac secondary prevention professionals; and in reports to funders. Authorship for publications will follow the uniform requirements for manuscripts submitted to biomedical journals.