The goal of palliative and supportive care is to improve patients’ quality of life (QoL). Patient-reported outcome measures (PROMs) are the gold standard for the assessment of QoL and symptoms; however, when self-reporting is complicated, PROMs are often substituted with proxy-reported outcome measures, such as clinician-reported outcome measures. The objective of this study was to assess the validity and reliability of the Japanese version of the Integrated Palliative care Outcome Scale (IPOS) for staff (IPOS-Staff).

This multicenter, cross-sectional observational study was conducted concurrently with the validation of the IPOS for patients (IPOS-Patient). Japanese adult patients with cancer and their staff were recruited. We assessed the characteristics of the patients and staff members, missing values, prevalence, and total IPOS scores. For the analysis of criterion validity, intra-rater, and inter-rater reliability, we calculated intraclass correlations (ICCs).

One hundred and forty-three patients completed the IPOS-Patient, and 79 medical staff members completed the IPOS-Staff. The most common missing values from IPOS-Staff were Family Anxiety (3.5%) and Sharing Feelings (3.5%). Over half of the patients scored themselves moderate or worse for Poor Mobility, Anxiety, and Family Anxiety, while staff members scored patients moderate or worse for Weakness, Anxiety, and Family Anxiety. For criterion validity (patient–staff agreement) as well as intra-rater and inter-rater reliability, ICCs ranged from 0.114 (Sharing Feelings) to 0.826 (Nausea), 0.720 (Anxiety) to 0.933 (Nausea), and −0.038 (Practical Problems) to 0.830 (Nausea), respectively.

The IPOS-Staff is easy to respond to; it has fair validity and reliability for physical items but poor for psycho-social items. By defining the context and objectives of its use and interpretation, the IPOS-Staff can be a useful tool for measuring outcomes in adult patients with cancer who cannot complete self-evaluations.