Psychometric Testing of the Self-care of Coronary Heart Disease Inventory Version 3.0
Victoria Vaughan Dickson, Paolo Iovino, Maddalena De Maria, Ercole Vellone, Rosaria Alvaro, Roberta Di Matteo, Alberto Dal Molin, Maura Lusignani, Barbara Bassola, Antonio Maconi, Tatiana Bolgeo, Bárbara Riegel
Abstract
BACKGROUND: In this updated Self-Care of Coronary Heart Disease Inventory (SC-CHDI) v3.0, items were added to better reflect the theory of self-care of chronic illness and revised based on recent research. The expanded SC-CHDI now reflects the theoretical concepts of self-care maintenance, monitoring, and management. OBJECTIVE: The aim of this study was to evaluate the psychometric properties of the SC-CHDI v3.0. METHODS: In a sample of adults with coronary heart disease, we tested the SC-CHDI v3.0 validity with confirmatory factor analysis. Reliability was calculated using Cronbach α, factor score determinacy coefficient, and global reliability index for multidimensional scales, with values > 0.70 considered adequate. RESULTS: The sample (n = 205) was predominantly male (79%) with a mean age of 65.3 ± 11.1 years. The self-care maintenance scale encompassed 2 distinct behaviors, namely, "illness related behaviors" and "health promoting behaviors," which reflect consulting and autonomous dimensions, respectively. The goodness-of-fit indices were adequate: χ2(25, N = 205) =31.86, P = .16, comparative fit index = 0.97, Tucker-Lewis Index = 0.95, root mean square error of approximation = 0.04 (90% confidence interval, 0.00-0.07), P = .705, and standardized root mean square residual = 0.045. Analysis of the new self-care monitoring scale yielded a single factor; goodness-of-fit indices were excellent: χ2(12, N = 205) =11.56, P = .48, comparative fit index = 1.00, Tucker-Lewis Index = 1.00, root mean square error of approximation < 0.001 (90% confidence interval, 0.000-0.07), P = .86, and standardized root mean square residual = 0.02. The self-care management scale had 2 dimensions of autonomous and consulting behavior with strong goodness-of-fit indices: χ2(7, N = 205) =6.57, P = .47, comparative fit index = 1.00, Tucker-Lewis Index = 1.00, root mean square error of approximation ≤ 0.001 (90% confidence interval, 0.00-0.08), P = .76, and standardized root mean square residual = 0.02. Reliability estimates were ≥0.80 for all scales. CONCLUSIONS: Our testing suggests that the SC-CHDI v3.0 is a sound measure of the essential elements of self-care for adults with coronary heart disease.