Advancing knowledge of self-care instruments

There is growing interest in self-care including those theory-based research instruments designed to measure self-care, such as the Self-Care of Heart Failure Index (SCHFI),1 the Self-Care of Chronic Illness Inventory (SC-CII),2 the Self-Care of Diabetes Inventory (SCODI),3 and the Self-Care of Chronic Obstructive Pulmonary Disease Inventory (SC-COPDI).4 All these instruments, and others available on the website https://self-care-measures.com, are based on the Middle-Range Theory of Self-Care of Chronic Illness,5 which provides a theoretical basis on which to develop and validate the self-care instruments of chronic diseases. These self-care instruments have been translated in several languages and their psychometric properties have been assessed in several studies. Among them we can cite the recent article by Bugajski and colleagues (2021)6 that evaluated the validity and reliability of the SC-COPDI in a U.S. sample of people with chronic obstructive pulmonary disease. In spite of the theoretical basis and other examples of psychometric evaluation available in the published literature, it is still common to see publications in which the reliability and validity of self-care instruments were assessed using outdated methods and techniques. For this reason. we want to provide some recommendations on how best to perform the psychometric analysis of the self-care instruments derived from the Middle-Range Theory of Self-care of Chronic illness. We believe that well-conducted validation study will help to advance knowledge of self-care and the self-care instruments used to study self-care. The self-care instruments are important in both research and clinical practice as they can help to identify people at risk of poor self-care who would benefit from specific educational interventions to increase their self-care and improve their clinical outcomes and quality of life