Further Evidence of Psychometric Performance of the Self-care of Diabetes Inventory in Adults With Type 1 and Type 2 Diabetes

Abstract

Background: The Self-care of Diabetes Inventory (SCODI) is a theory-based tool that measures self-care, a key strategy in the appropriate treatment of diabetes. However, despite the clinical differences between people with Type 1 Diabetes Mellitus (T1DM) and Type 2 Diabetes Mellitus (T2DM), the psychometric properties of the SCODI were only tested in mixed samples.

Purpose: This study aims to test the psychometric performances of the SCODI in two separate groups of adults with T1DM and T2DM.

Methods: This is a secondary analysis from two previous multicentre cross-sectional observational studies involving patients with T1DM (n = 181) and T2DM (n = 540). We tested dimensionality with confirmatory factor analysis and reliability with a multidimensional model-based coefficient for every scale of the SCODI: self-care maintenance, self-care monitoring, self-care management, and self-care self-efficacy.

Results: We found that the SCODI showed the same dimensionality, with minimal variation in factor loadings for each factor and each scale among T1DM and T2DM groups. High reliability for each scale in both groups was also found (self-care maintenance: T1DM = 0.86, T2DM = 0.83; self-care monitoring: T1DM = 0.84, T2DM = 1.00; self-care management: T1DM = 0.87, T2DM = 0.86; self-care self-efficacy: T1DM = 0.88; T2DM = 0.86).

Conclusion: The SCODI can be used for measuring self-care in people with T1DM, T2DM, or mixed groups using identical scoring procedures. Considering the well-known differences between Type 1 and Type 2 diabetes diseases and patients' characteristics, our results support the generalizability of the self-care theory on which the instrument is based.

Keywords: Diabetes Mellitus; Diabetes Mellitus Type 1; Diabetes Mellitus Type 2; Instrument development; Psychometrics; Self-care; Self-efficacy; Self-management.