Initial validation of the Death and Dying Distress Scale for the assessment of death anxiety in patients with advanced cancer

Abstract

Context: The experience of death anxiety in patients with advanced cancer has been understudied partly because of the lack of a tailored measure for this population. The Death and Dying Distress Scale (DADDS) was constructed to address this gap. Although an initial version of this instrument has shown promising psychometric properties, validation of the finalized version is needed.

Objectives: This study aims to validate the recent 15-item DADDS by examining its factor structure and construct validity.

Methods: Sixty participants with advanced or metastatic cancer were recruited from the Princess Margaret Cancer Centre, University Health Network, Toronto, Canada, into a pilot trial of a psychological intervention. This article analyzes the baseline measures on death anxiety, depressive symptoms (Patient Health Questionnaire-9, Structured Clinical Interview for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision, Axis 1 Disorders), generalized anxiety (Generalized Anxiety Disorder-7), and preparation for end of life (Quality of Life at the End of Life-Cancer Scale). Exploratory factor analysis was conducted. Construct validity was assessed by correlations between measures.

Results: Factor analysis revealed a dominant single factor explaining more than 75% of the shared variation between items. Factor loadings were high, ranging from 0.57 to 0.86. Item communalities were evenly ranged from 0.33 to 0.75 and with the 15:1 variable to factor ratio, suggest the viability of parameter estimates despite the small sample size. Cronbach's alpha was 0.95. Death anxiety was associated with less preparation for end of life (r = -0.68, P < 0.0001), more generalized anxiety (r = 0.63, P < 0.0001), and more depressive symptom severity (r = 0.50, P < 0.0001). Individuals with major depression had greater death anxiety than the nondepressed (mean difference = 17; 95% CI = 1.5-33), as did individuals with minor depression (mean difference = 25; 95% CI = 10-41).

Conclusion: The DADDS is a valid measure of death anxiety in patients with advanced cancer. It may provide useful information in the assessment and treatment of distress in patients near the end of life.

Keywords: Death anxiety; advanced cancer; measurement; palliative care.