Psychological well-being and quality of care: a factor-analytic examination of the palliative care outcome scale

Context: The Palliative Care Outcome Scale (POS) is a widely used outcome measure in palliative care research, and has good psychometric properties. It has been used for clinical or research purposes in specialist cancer centers, nursing homes, day hospice units, and hospice settings in a growing number of countries. However, the POS has not yet been examined using factor analysis.

Objective: The aim of the present study was to examine the internal factor structure of the POS.

Methods: Confirmatory and exploratory factor analyses were used for secondary analysis of two existing POS data sets of British patients, most of whom were cancer patients.

Results: We began with a confirmatory factor analysis (CFA), which indicated that the POS is not a unidimensional scale. This was followed by an exploratory factor analysis that suggested two factors-one reflecting a psychological well-being dimension and the other consisting of three items relating to the standard of professional care. A similar two-factor structure also was identified in the second sample using CFA.

Conclusion: The POS appears to capture two factors, psychological status and quality of care, and to have three items that function independently (family anxiety, symptoms, and pain control). Our findings suggest that future evaluations of palliative care services should include assessment not only of symptoms and well-being or quality of life, but also of quality of care, and that unidimensional measures will not capture all relevant aspects in palliative care.