A brief, patient- and proxy-reported outcome measure in advanced illness: Validity, reliability and responsiveness of the Integrated Palliative care Outcome Scale (IPOS)

Abstract

Background: Few measures capture the complex symptoms and concerns of those receiving palliative care. Aim: To validate the Integrated Palliative care Outcome Scale, a measure underpinned by extensive psychometric development, by evaluating its validity, reliability and responsiveness to change. Design: Concurrent, cross-cultural validation study of the Integrated Palliative care Outcome Scale – both (1) patient self-report and (2) staff proxy-report versions. We tested construct validity (factor analysis, known-group comparisons, and correlational analysis), reliability (internal consistency, agreement, and test–retest reliability), and responsiveness (through longitudinal evaluation of change). Setting/participants: In all, 376 adults receiving palliative care, and 161 clinicians, from a range of settings in the United Kingdom and Germany Results: We confirm a three-factor structure (Physical Symptoms, Emotional Symptoms and Communication/Practical Issues). Integrated Palliative care Outcome Scale shows strong ability to distinguish between clinically relevant groups; total Integrated Palliative care Outcome Scale and Integrated Palliative care Outcome Scale subscale scores were higher – reflecting more problems – in those patients with ‘unstable’ or ‘deteriorating’ versus ‘stable’ Phase of Illness (F = 15.1, p < 0.001). Good convergent and discriminant validity to hypothesised items and subscales of the Edmonton Symptom Assessment System and Functional Assessment of Cancer Therapy–General is demonstrated. The Integrated Palliative care Outcome Scale shows good internal consistency (α = 0.77) and acceptable to good test–retest reliability (60% of items kw > 0.60). Longitudinal validity in form of responsiveness to change is good. Conclusion: The Integrated Palliative care Outcome Scale is a valid and reliable outcome measure, both in patient self-report and staff proxy-report versions. It can assess and monitor symptoms and concerns in advanced illness, determine the impact of healthcare interventions, and demonstrate quality of care. This represents a major step forward internationally for palliative care outcome measurement.

Psychometric properties of the Czech Integrated Palliative Outcome Scale: Reliability and content validity analysis

“…Cronbach alpha showed a high internal consistency of the Czech version of IPOS which is consistent with other studies (12,13,15). IPOS was completed twice by 14 patients and test-retest reliability was confirmed by a sufficient intraclass-correlation coefficient.…”

“…IPOS was found to have excellent reliability (12)(13)(14)(15)(16) and face and content validity was also confirmed in several studies using cognitive interviews (11,17,18) Convergent validity has been confirmed for the original and German IPOS (13), Japanese version of IPOS (14) and French IPOS (16). In many other countries the process of validation is ongoing and all language version which are currently available, such as Portuguese, Polish, Greek etc., can be found online (www.pos-pal.org).This study aims to provide a valid version of IPOS in Czech and to report the psychometric properties of IPOS from this first pilot Czech study.…”

“…In our study, we were limited by the size of the overall sample not sufficient to apply Confirmatory factor analysis (CFA). Murtagh and her colleagues identified three factors in IPOS using CFA -Physical Symptoms, Emotional Symptoms and Communication/Practical Issues (13). This suggests that subscales could differ according to socio-cultural context or that we need more data for testing our two-factor model and the three-factor model using CFA and to compare which of these models is more precise for our population.…”

The AMBER care bundle for hospital inpatients with uncertain recovery nearing the end of life: the ImproveCare feasibility cluster RCT

“…61 A recent study provides evidence that the IPOS is a robust, valid and reliable measure and would provide discrimination between relevant groups. 62 We identified among 373 participants that the IPOS can discriminate well between patients with different illness and functional characteristics. For example, in the known-group comparisons (during our testing of construct validity), the total IPOS and subscale scores discriminated well between patients who were in an unstable/deteriorating phase compared with those in a more stable phase of illness (total IPOS: F = 15.0, p < 0.001; Patient/family anxiety and communication subscale:…”

Challenges in the cultural adaptation of the German Myeloma Patient Outcome Scale (MyPOS): an outcome measure to support routine symptom assessment in myeloma care

“…The initial validation comprised 380 patients at different disease stages in the UK [22]. The MyPOS is a module of the Integrated Palliative/Patient care Outcome Scale (IPOS) [23][24][25], a short, multidimensional questionnaire to assess palliative care concerns in patients with advanced disease. The MyPOS takes the core items of the POS and extends them with myeloma-specific concerns.…”