Background
The aim of this study was to examine the psychometric properties, factor structure, measurement invariance, internal consistency reliability and construct validity of the Me and My Disease Scale – a tool for state hope measurement for adults suffering from chronic medical conditions.

Participants and procedure
Two clinical groups, patients with type 2 diabetes (DM) (n = 278) just before and 1 month after introducing insulin treatment, and cardiac patients (n = 232) five days and one month after their first uncomplicated myocardial infarction (MI), participated in the study. Cognitive appraisal, emotions and depression (MI group) were measured to establish the construct validity of the scale.

Results
A single-factor model which consisted of 4 items was established. The structure was characterized by good measurement model fit and satisfactory indicators of reliability for the MI subgroup. A less satisfactory model fit was obtained for the DM subgroup – this may point to the impact of specific medical conditions on the scale. Furthermore, the findings indicated metric invariance for the scale. The moderate correlations between hope and cognitive appraisal, emotion and depression confirm the construct validity of the scale.

Conclusions
The Me and My Disease Scale is characterized by satisfactory psychometric parameters and can be used in scientific research to measure hope as a dimension of cognition and to compare the relationships between hope and other variables in medical patients. However, caution should be taken during analysis when comparing means between clinical groups.