The study aimed to assess the reliability and validity of the IPOS-Pol for patient self-reporting.

Patients (>18 years of age) with advanced cancer admitted to three palliative care centers (inpatient units and home-based) were recruited to a multicenter, cross-sectional, observational, prospective study. Participants provided responses to the IPOS-Pol Patient version and the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire – Core 15 – Palliative Care (EORTC QLQ-C15-PAL) Polish version at baseline (T1) and four to seven days later (T2). We assessed test–retest reliability, internal consistency, and construct validity of the tool.

One hundred and eighty patients were included. Test–retest reliability demonstrated no statistically significant differences in the average outcomes of the IPOS-Pol between T1 and T2 (27.2 ± 9.2 vs. 26.5 ± 8.7; p > 0.05). The intra-class correlation coefficient between T1 and T2 was r = 0.83 (p < 0.0001), the intra-class correlation coefficient for test–retest reliability of the IPOS-Pol items ranged from 0.63 to 0.84 (p < 0.0001), and the Cronbach's α coefficient for internal consistency was 0.773. The correlation coefficient between the IPOS-Pol and EORTC QLQ-C15-PAL total score was 0.79 (p < 0.001).

The patient version of the Polish adaptation of IPOS is a valid and reliable outcome measure for assessing symptoms and concerns of individuals receiving palliative care, as well as the quality of care provided.