Development and Psychometric Evaluation of the Knowledge Scale for Adults With Congenitally Malformed Hearts

Background and Research Objective: Adults with congenitally malformed hearts have knowledge gaps regarding their heart condition, and their level of knowledge is not routinely assessed during follow-up. One reason for this is that there are few validated, user-friendly questionnaires to assess knowledge about congenital heart disease and its effects on daily life. Failure to identify low levels of knowledge could lead to less motivated and insecure individuals not actively involved in treatment and care of their heart condition. Therefore, the objective of this study was to develop and test a knowledge scale for adults with congenitally malformed hearts. Participants and Methods: The development and psychometric evaluation of the Knowledge Scale for Adults With Congenitally Malformed Hearts (KnoCoMH) followed 2 phases: (1) development and evaluation of the initial version, with face validity and content validity assessed by experts and adults with congenitally malformed hearts, and (2) evaluation and refinement of the KnoCoMH in adults with congenitally malformed hearts, including item difficulty level, internal consistency, and test-retest reliability. Results: The development and evaluation of a knowledge scale for adults with congenitally malformed hearts resulted in the KnoCoMH including 46 items in 4 domains: General Knowledge, with a Kuder-Richardson formula 20 (KR-20) value of 0.68; Medical Treatment, with a KR-20 value of 0.74; Endocarditis Prophylaxis, with a KR-20 value of 0.90; and Contraceptives and Pregnancy, with a KR-20 value of 0.65. Test-retest evaluation showed significant correlations between 0.50 and 0.67 (P < .01) in all 4 domains. There was good variation in item difficulty, with a mean value of 0.56 in General Knowledge, 0.62 in Medical Treatment, 0.33 in Endocarditis Prophylaxis, and 0.48 in Contraceptives and Pregnancy. Conclusions: The KnoCoMH has acceptable psychometric properties for most of the knowledge domains included. It can be used for evaluating knowledge among adults with congenitally malformed hearts and its associations with other outcomes. However, further studies are advisable to test construct validity, predictive validity, and responsiveness.