Illness Identity Questionnaire in Ecuadorian adults: analysis of psychometric properties

Illness identity analyzes the way in which a chronic health condition is integrated into personal identity. So far, there is no record of the analysis of the construct in Spanish-speaking population. The construction four illness identity factors have been distinguished: rejection, engulfment, acceptance and enrichment. Rejection and engulfment are related to poor psychological adjustment and physical malfunctioning in the patient, whereas, acceptance and enrichment are related to adaptive functioning. In rejection the chronic illness is not accepted as the patient’s self-identity and is interpreted as threatening or inappropriate. Engulfment describes the way in which the illness dominates a person’s identity, causing individuals to define themselves completely in terms of their illness. In acceptance people admit their new condition as part of themselves without feeling overwhelmed by it. Enrichment, refers to individuals for whom the disease is a generator of positive changes that allow them to grow as a person, which is beneficial to their identity; this categorization has been assessed by the Illness Identity Questionnaire (IIQ) (Oris et al., 2016). The objective of the study was to adapt and establish the psychometric properties of the Illness Identity Questionnaire (IIQ) in chronically ill adults. Linguistic adaptation of the IIQ from English to Spanish was performed. The questionnaire was translated from English to Spanish; the forward and back-translation guidelines of the International Test Commission (ITC, 2016), and the Standards for Educational and Psychological Testing (AERA, 2018). 450 Ecuadorian adults diagnosed with hypertension and diabetes participated in the study. Statistical and Psychometric issues: confirmatory factor analysis (CFA) and multigroup confirmatory factor analysis (MG-CFA) were performed with the Linear Structural Relations program (LISREL 8.5). A stepwise analysis was used to establish the models in the single-group CFA and the multi-group MG-CFA (Byrne, 2021). The complete sample was analyzed and the best factorial model for the CIE scale was sought. Once the best model was found, the MG-CFA was carried to evaluate the degree of invariance of the CIE structure in the samples of men and women. In the MG-CFA, we first checked for configural invariance, where no parameter is constrained. Then, the metric invariance was evaluated, where the factor loadings in both samples and the correlations between the latent variables corresponding to each factor were restricted. The results of both confirmatory factor analyses were evaluated with the fit indices: Satorra-Bentler Scale chi-square test (SB-Sχ2), root mean square error of approximation (RMSEA), standardized root means square residual (SRMR), and the comparative fit index (CFI). The internal consistency coefficients (Omega), the mean and standard deviation of each factor, and of each subscale used in the study were calculated. As a result, the first linguistic adaptation of the Illness Identity Questionnaire (CIE) into Spanish was obtained, in a sample of 450 Ecuadorian adults with a diagnosis of chronic diseases. By means of confirmatory factor analysis, a model was obtained that reproduced the structure of four factors of illness identity, coinciding with the original instrument: rejection, engulfment, acceptance and enrichment, in the total sample. The multigroup confirmatory factor analysis, where the sex variable was considered as a moderating variable, was able to verify the configural invariance and the metric invariance of the CIE. The CIE shows evidence of convergent validity and discriminant validity with the active coping and avoidant coping scales of the Brief COPE questionnaire. The CIE has an adequate reliability. The CIE obtained in this study is very useful for research and practice in the field of Health Psychology.