The Construct Validity of the Social and Spiritual Items of the Utrecht Symptom Diary – 4 Dimensional

Abstract

Context Patients facing a life-limiting illness experience multidimensional symptoms, problems, and needs requiring personalized care. The Utrecht Symptom Diary – 4 Dimensional (USD-4D) is a Patient Reported Outcome Measure (PROM) that supports daily multidimensional symptom management through identification, monitoring and discussing of multidimensional symptoms and care needs. The construct validity of this PROM has yet to be established.

Objective This study aimed to assess the construct validity of the social and spiritual items of the USD-4D in a population of Dutch patients in the palliative phase of their illness.

Methods Construct validity is defined as the “degree to which the scores of a PROM are consistent with hypotheses based on the assumption that the PROM validly measures the construct to be measured.” Since the USD-4D does not measure one construct, the construct validity of the social and spiritual items was assessed through hypotheses testing following the criteria of the COSMIN initiative (COnsensus-based Standards for the selection of health Measurement Instruments). This study comprised patients coming from two distinct observational cohorts: a hospice cohort and the MuSt-PC cohort, a national cohort of patients across several care settings. Patients included in the hospice cohort were adult patients with an estimated life-expectancy of 3 months or less and any underlying disease. The MuSt-PC cohort comprised adult patients with an estimated life-expectancy of 12 months or less and any underlying disease in the home, care home, hospital, or hospice setting. Patients unable or unwilling to self-assess their symptoms were excluded. Construct validity was assessed by means of hypothesis testing for every individual item and was established when ≥75% of the formulated hypotheses were confirmed. Hypotheses were literature and expert driven. A total of 19 hypotheses were formulated and tested.

Results 897 patients were included in the final analysis. Of these patients 53% was female, 81% had cancer as their primary diagnosis and 85% received care in a hospice. For every item, at least 75% of hypotheses were confirmed. One hypothesis for the item ‘I can let my loved ones go’ was rejected.

Conclusions This study confirmed the construct validity on the social and spiritual items of the USD-4D for Dutch hospice patients in the palliative phase of their illness. The USD-4D is suitable for signaling and monitoring multidimensional symptoms and needs. Generalizability to other settings is challenging due to lack of patient outcome data from these settings.