Dignity in Chronic Illness: Development and Validation of the Patient Dignity Inventory for Chronic Illness (PDI-CI)

Abstract

Introduction. Dignity is a core ethical and clinical dimension in oncology nursing and in illness trajectories characterized by high symptom burden and existential distress. The Patient Dignity Inventory (PDI), originally developed in oncology and palliative care, is widely used to assess dignity-related distress. However, its original structure may be less suitable for chronic care settings. The aim of this study was to develop and validate a version adapted to chronic illness (PDI-CI), theoretically and psychometrically consistent with the specific needs of these patients.

Methods. A psychometric validation study was conducted between June 2024 and May 2025 involving 240 adults with chronic conditions. The 11-item PDI-CI was administered together with the Psychological Well-Being Scale (PWBS-42) to assess convergent validity. A subgroup completed the questionnaire again after two weeks to evaluate test-retest reliability. Analyses included Rasch modelling, targeting, internal consistency using the Person Separation Index (PSI) and Cronbach’s alpha, test-retest reliability, and Differential Item Functioning (DIF) by age and gender.

Results. Rasch analysis showed good model fit and adequate targeting to the sample’s level of distress. Items performed consistently with the theoretical construct. Internal consistency was high (PSI = 0.83; α = 0.93), and test-retest reliability was excellent (ρ = 0.904; p < 0.001). Convergent validity showed significant correlations in the expected direction, indicating that greater dignity-related distress was associated with poorer psychological well-being. DIF analyses showed no clinically relevant bias by age or gender.

Discussion. The PDI-CI is a brief, reliable, and psychometrically robust instrument for assessing dignity in chronic illness. Its use may support the early identification of existential needs and enable personalized nursing interventions. Its applicability within oncology care pathways, which are increasingly characterized by chronic disease trajectories, represents a relevant area for future research.