Development of a Patient-Reported Palliative Care-Specific Health Classification System: The POS-E

Abstract

BackgroundGeneric preference-based measures are commonly used to estimate quality-adjusted life-years (QALYs) to inform resource-allocation decisions. However, concerns have been raised that generic measures may be inappropriate in palliative care.ObjectiveOur objective was to derive a health-state classification system that is amenable to valuation from the ten-item Palliative Care Outcome Scale (POS), a widely used patient-reported outcome measure in palliative care.MethodsThe dimensional structure of the original POS was assessed using factor analysis. Item performance was assessed, using Rasch analysis and psychometric criteria, to enable the selection of items that represent the dimensions covered by the POS. Data from six studies of patients receiving palliative care were combined (N = 1011) and randomly split into two halves for development and validation. Analysis was undertaken on the development data, and results were validated by repeating the analysis with the validation dataset.ResultsFollowing Rasch and factor analyses, a classification system of seven items was derived. Each item had two to three levels. Rasch threshold map helped identify a set of 14 plausible health states that can be used for the valuation of the instrument to derive a preference-based index.ConclusionCombining factor analysis and Rasch analysis with psychometric criteria provides a valid method of constructing a classification system for a palliative care-specific preference-based measure. The next stage is to obtain preference weights so the measure can be used in economic evaluations in palliative care.Electronic supplementary materialThe online version of this article (doi:10.1007/s40271-017-0224-1) contains supplementary material, which is available to authorized users.

A Rasch Analysis of the Integrated Palliative Care Outcome Scale

“…2 The POS has undergone psychometric evaluation using traditional methods such as reliability, 1 exploratory factor analysis, 3,4 and confirmatory factor analysis. 3 Rasch analysis has been used with selected POS items to develop a palliative care health classification system and supported its internal validity 5 ; however, as yet, Rasch analysis has not been used with the IPOS and conversion tables have not been produced. Cognitive interviews evaluating the acceptability and utility of the IPOS showed that the questionnaire was easy to comprehend, acceptable, and not burdensome to complete.…”

Developing a Short-Form Version of the HIV Disability Questionnaire (SF-HDQ) for Use in Clinical Practice: A Rasch Analysis

“…We considered ≥ 0.70 as acceptable [31,40]. We assessed the Chi Square statistic (χ2) with Bonferroni adjusted signi cance levels (alpha value = 0.05/number of items in the original domain), but did not consider it a determinant of model t given its sensitivity to large sample sizes, which can overestimate lack of model t [41].…”

Patient centered outcome measurement in health economics: beyond EQ-5D and the Quality-Adjusted Life-Year—where are we now?

“…Nevertheless, moving beyond generic health measures such as EQ-5D to form QALYs, is an active area of investigation in evaluation of palliative and end of life care, with research moving in two directions, employing differing value judgements. The first remains within the general QALY paradigm whilst relaxing the value judgement around use of generic health measures, in favour of using a 'health' measure that reflects health issues faced by those receiving palliative care (11). The second is more radical, questioning more of the value judgements associated with QALY maximisation (9) and shifting focus towards capability wellbeing amongst those at end of life (12)(13)(14) and persons close to them (15).…”

“…The first tranche of research builds on an existing, widely used measure, the Palliative care Outcomes Scale (POS) and its forerunner, the Support Team Assessment Schedule (16), to develop a new scale, the POS-E. POS-E has been derived from the existing ten-item, five level POS (11). This is a point at which practical considerations enter: the POS scale itself is too large to feasibly produce a full value set, and so a derived seven-item scale has been generated, with each item having smaller numbers (two or three) of levels (11) (12).…”

“…The first tranche of research builds on an existing, widely used measure, the Palliative care Outcomes Scale (POS) and its forerunner, the Support Team Assessment Schedule (16), to develop a new scale, the POS-E. POS-E has been derived from the existing ten-item, five level POS (11). This is a point at which practical considerations enter: the POS scale itself is too large to feasibly produce a full value set, and so a derived seven-item scale has been generated, with each item having smaller numbers (two or three) of levels (11) (12). Both pilot (17) and full (14) valuation exercises with members of the public, using a technique known as best-worst scaling (14,17,18), have recently been published; values are generated between full capability and no capability, and death is assumed to be a state of no capability (18).…”