Antonella Granieri ¹ Isabella Giulia Franzoi ^1,2* Maria Domenica Sauta ¹ Alessandro Marinaccio ³ Carolina Mensi ⁴ Sabrina Rugarli ⁴ Enrica Migliore ⁵ Ilaria Cozzi ⁶ Domenica Cavone ⁷ Luigi Vimercati ⁷ Federica Grosso ⁸ Marinella Bertolotti ⁸ Giulia Raimondi ⁹ Marco Innamorati ¹⁰ Michela Bonafede ³

• ¹ Department of Psychology, University of Turin, Turin, Piedmont, Italy
• ² University of Turin, Turin, Italy
• ³ Occupational and Environmental Medicine, Epidemiology and Hygiene Department, Italian Workers’ Compensation Authority (INAIL), Rome, Italy
• ⁴ IRCCS Ca 'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
• ⁵ University Hospital of the City of Health and Science of Turin, Turin, Italy
• ⁶ Departement of Epidemiology, Regional Health Service of Lazio, Rome, Italy
• ⁷ Department of Interdisciplinary Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
• ⁸ SS National Hospital. Antonio and Biagio and Cesare Arrigo, Alessandria, Italy
• ⁹ Institute of Immaculate Dermatology (IRCCS), Rome, Italy
• ¹⁰ Department of Human Science, European University of Rome, Rome, Lazio, Italy

Objective: The diagnosis of malignant mesothelioma (MM) can be devastating for both patients and caregivers, who may experience intense suffering from a physical, psychological, and interpersonal perspective. Despite the extensive literature on caregiver distress, there is a lack of validated measures to provide evidence of psychological distress of caregivers of MM patients. Therefore, in a previous study we developed the Mesothelioma Psychological Distress Tool-Caregivers (MPDT-C) to evaluate the specific profile of psychological distress in this population. This paper describes the item selection, factor analysis, and psychometric evaluation of the revised MPDT-C. Methods: The analyses of this work first aimed to confirm the previous factorial structure. In the case of nonfit, it aimed to find an alternative structure and causes of nonfit in the model.Examination of the fit of the factorial model was conducted using a Bayesian approach. Results: The final version of the MPDT-C is a 7-item self-report questionnaire consisting of one factor (Burden for the caregiver). Conclusions: Having a short self-report questionnaire to assess the psychological distress experienced by caregivers of MM patients has several advantages. First, it is suited to epidemiological studies where multiple variables and measures are involved. Second, it is easy to administer and does not take much time to complete. Therefore, the MPDT-C can also be administered in clinical contexts, perhaps when MM patients attend follow-up medical evaluation. Lastly, short measures are less affected by cognitive fatigue, which is very common in a long battery of tests and could affect response reliability.