Hospice patients' participation in choice experiments to value supportive care outcomes

An analysis of the construct validity and responsiveness of the ICECAP-SCM capability wellbeing measure in a palliative care hospice setting

BACKGROUND

For outcome measures to be useful in health and care decision-making, they need to have certain psychometric properties. The ICECAP-Supportive Care Measure (ICECAP-SCM), a seven attribute measure (1. Choice, 2. Love and affection, 3. Physical suffering, 4. Emotional suffering, 5. Dignity, 6. Being supported, 7. Preparation) developed for use in economic evaluation of end-of-life interventions, has face validity and is feasible to use. This study aimed to assess the construct validity and responsiveness of the ICECAP-SCM in hospice inpatient and outpatient settings.

METHODS

A secondary analysis of data collated from two studies, one focusing on palliative care day services and the other on constipation management, undertaken in the same national hospice organisation across three UK hospices, was conducted. Other quality of life and wellbeing outcome measures used were the EQ-5D-5L, McGill Quality of Life Questionnaire - Expanded (MQOL-E), Patient Health Questionnaire-2 (PHQ-2) and Palliative Outcomes Scale Symptom list (POS-S). The construct validity of the ICECAP-SCM was assessed, following hypotheses generation, by calculating correlations between: (i) its domains and the domains of other outcome measures, (ii) its summary score and the other measures' domains, (iii) its summary score and the summary scores of the other measures. The responsiveness of the ICECAP-SCM was assessed using anchor-based methods to understand change over time. Statistical analysis consisted of Spearman and Pearson correlations for construct validity and paired t-tests for the responsiveness analysis.

RESULTS

Sixty-eight participants were included in the baseline analysis. Five strong correlations were found with ICECAP-SCM attributes and items on the other measures: four with the Emotional suffering attribute (Anxiety/depression on EQ-5D-5L, Psychological and Burden on MQOL-E and Feeling down, depressed or hopeless on PHQ-2), and one with Physical suffering (Weakness or lack of energy on POS-S). ICECAP-SCM attributes and scores were most strongly associated with the MQOL-E measure (0.73 correlation coefficient between summary scores). The responsiveness analysis (n = 36) showed the ICECAP-SCM score was responsive to change when anchored to changes on the MQOL-E over time (p < 0.05).

CONCLUSIONS

This study provides initial evidence of construct validity and responsiveness of the ICECAP-SCM in hospice settings and suggests its potential for use in end-of-life care research.

German tariffs for the ICECAP-Supportive Care Measure (ICECAP-SCM) for use in economic evaluations at the end of life

OBJECTIVES

Economic evaluations often use preference-based value sets (tariffs) for health-related quality of life to quantify health effects. For wellbeing at the end of life, issues beyond health-related quality of life may be important. Therefore, the ICECAP Supportive Care Measure (ICECAP-SCM), based on the capability approach, was developed. A validated German ICECAP-SCM version was published recently. However, tariffs for the German ICECAP-SCM are not available. Therefore, the aim was to determine tariffs for the ICECAP-SCM based on preferences of the German general population.

METHODS

An online sample of 2996 participants completed a best-worst scaling (BWS) and a discrete choice experiment (DCE). BWSs required participants to choose the best and worst statement within the same capability state, whereas DCEs required participants to trade-off between two capability states. First, BWS and DCE data were analyzed separately. Subsequently, combined data were analyzed using scale-adjusted conditional logit latent class models. Models were selected based on the stability of solutions and the Bayesian information criterion.

RESULTS

The two latent class model was identified to be optimal for the BWS, DCE, and combined data, and was used to derive tariffs for the ICECAP-SCM capability states. BWS data captured differences in ICECAP-SCM scale levels, whereas DCE data additionally explained interactions between the seven ICECAP-SCM attributes.

DISCUSSION

The German ICECAP-SCM tariffs can be used in addition to health-related quality of life to quantify effectiveness in economic evaluations. The tariffs based on BWS data were similar for Germany and the UK, whereas the tariffs based on combined data varied. We would recommend to use tariffs based on combined data in German evaluations. However, only results on BWS data are comparable between Germany and the UK, so that tariffs based on BWS data should be used when comparing results between Germany and the UK.

Valuing end-of-life care: translation and content validation of the ICECAP-SCM measure

Background

The evaluation of care strategies at the end of life is particularly important due to the globally increasing proportion of very old people in need of care. The ICECAP-Supportive Care Measure is a self-complete questionnaire developed in the UK to evaluate palliative and supportive care by measuring patient’s wellbeing in terms of ‘capability’. It is a new measure with high potential for broad and international use. The aims of this study were the translation of the ICECAP-Supportive Care Measure from English into German and the content validation of this version.

Methods

A multi-step and team-based translation process based on the TRAPD model was performed. An expert survey was carried out to assess content validity. The expert panel (n = 20) consisted of four expert groups: representative seniors aged 65+, patients aged 65+ living in residential care, patients aged 65+ receiving end-of-life care, and professionals in end-of-life care.

Results

The German version of the ICECAP-Supportive Care Measure showed an excellent content validity on both item- and scale-level. In addition, a high agreement regarding the length of the single items and the total length of the questionnaire as well as the number of answer categories was reached.

Conclusions

The German ICECAP-SCM is a valid tool to assess the quality of life at the end of life that is suitable for use in different settings. The questionnaire may be utilized in multinational clinical and economic evaluations of end-of-life care.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12904-021-00722-5.