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

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.

Discovering the hidden benefits of cognitive interviewing in two languages: The first phase of a validation study of the Integrated Palliative care Outcome Scale.

BACKGROUND: The Integrated Palliative care Outcome Scale is a newly developed advancement of the Palliative care Outcome Scale. It assesses patient-reported symptoms and other concerns. Cognitive interviewing is recommended for questionnaire refinement but not adopted widely in palliative care research. AIM: To explore German- and English-speaking patients' views on the Integrated Palliative care Outcome Scale with a focus on comprehensibility and acceptability, and subsequently refine the questionnaire. METHODS: Bi-national (United Kingdom/Germany) cognitive interview study using 'think aloud' and verbal probing techniques. Interviews were audio-recorded, transcribed verbatim and analysed using thematic analysis and pre-defined categories. Results from both countries were collated and discussed. The Integrated Palliative care Outcome Scale was then refined by consensus. SETTING/PARTICIPANTS: Purposely sampled patients from four palliative care teams in palliative care units, general hospital wards and in the community. RESULTS: A total of 15 German and 10 UK interviews were conducted. Overall, comprehension and acceptability of the Integrated Palliative care Outcome Scale were good. Identified difficulties comprised the following: (1) comprehension problems with specific terms (e.g. 'mouth problems') and length of answer options; (2) judgement difficulties, for example, due to the 3-day recall for questions; and (3) layout problems. Combining the results from both countries (e.g. regarding 'felt good about yourself') and discussing them from both languages' perspectives resulted in wider consideration of the items' meaning, enabling more detailed refinement. CONCLUSION: Cognitive interviewing proved valuable to increase face and content validity of the questionnaire. The concurrent approach in two languages - to our knowledge the first such approach in palliative care - benefited the refinement. Psychometric validation of the refined Integrated Palliative care Outcome Scale is now underway.