Analysis of the psychometric properties of the Sense of Coherence scale (SOC-13) in patients with cardiovascular risk factors: a study of the method effects associated with negatively worded items

PURPOSE: The objectives of this study were to analyze the psychometric properties of the Sense of Coherence scale (SOC-13), determine the role of the method effect in the performance of the instrument, and identify the relationship with health perception, quality of life, and sleep quality in patients at cardiovascular risk. METHODS: The final sample consisted of 293 patients at cardiovascular risk, with a mean age of 61.9 years (SD = 8.8), 49.8% of whom were women. The SOC-13, the Patient Health Questionnaire (PHQ-9), and the Medical Outcomes Study-Sleep Scale (MOS-Sleep) were administered. In addition, the participant's self-perceived health and quality of life were also evaluated. All analyses were carried out with SPSS 26.0 and EQS 6.1 statistical software. RESULTS: The results showed adequate reliability for the SOC-13, with a Cronbach's alpha of .789. The fit of the structures was not adequate in any of the cases (.26 to .62 for one factor, .26 to.73 for three factors, .20 to .54 for one second-order factor, and .25, .42, and .54 for three first-order factors). The three structure models showed an improved fit when adding a latent factor resulting from the method effect (.6 to .85 for one factor, .11 to.90 for three factors, and .11 to .96 for one second-order factor). Moreover, positive correlations were found with health perception, perceived quality of life, and perceived sleep quality. CONCLUSION: The SOC-13 is a suitable instrument for patients with cardiovascular risk in Spain, and it is also an indicator of health perception, quality of life, and perceived quality of sleep. Control of the method effect improves the fit of the instrument’s structure. As a future direction, it is recommended to conduct new studies in this and other samples and using different versions of the SOC. TRIAL REGISTRATION: International Standard Randomized Controlled Trial Number: ISRCTN76069254, 08/04/2015 retrospectively registered.