We sought to identify all generic PROMs for children and young people, and then sought evidence from peer-reviewed publications describing studies conducted to evaluate the psychometric performance of PROMs when using English-language versions of the questionnaires. We separately appraised instruments that were generic (meant to be suitable for all children), chronic-generic (intended for to be suitable for children with health conditions), or PBMs. We also considered evidence separately depending on whether the research had been conducted with general populations or with children and young people affected by neurodisability.
We identified 41 potentially eligible PROMs, and identified 126 papers that reported evidence of the psychometric performance of 25 PROMs using English-language versions. Twelve candidate PROMs were selected as having more favourable evidence regarding their psychometric performance. Robust evidence was lacking in one or more respects to support the psychometric properties for all candidate PROMs appraised in this review, both in general populations and with children and young people affected by neurodisability. No evidence was found to support the responsiveness of any of the candidate PROMs to detect meaningful change in either general population or neurodisability.
We identified those aspects of health assessed by candidate generic PROMs through the systematic review, and coded these pragmatically using the WHO ICF-CY. Each PROM questionnaire assesses a range of constructs, but each does so in a slightly different way. The most notable difference was in how some PROM questions assess functioning as what people do, or can do, and other questions assess well-being as how people feel about their health. A few PROMs focus predominantly on either functioning or well-being, but all of our candidate PROMs conflated these concepts. As with our previous note on defining outcomes above, it is necessary to audit closely how the constructs measured by PROMs are defined, and whether or not these are consistent with the style and context of the questions being asked.
For children aged 8 to 18 years, there is favourable psychometric evidence for the KIDSCREEN, including Rasch analysis in general populations, and for the KIDSCREEN-52 with children with cerebral palsy. The Healthy Pathways is a promising instrument with some good evidence in favour, including from Rasch analysis; however, only two recent papers are published. The DISABKIDS was the only eligible chronic-generic instrument for which favourable evidence was found of psychometric performance in children and young people affected by chronic conditions, including neurodisability. The version of DISABKIDS Smileys-6, aimed at children 4 to 7 years old, was the only competitive candidate PROM to utilise emoticons in the response options. This was something preferred by children, young people and
parents in the qualitative research. The PedsQL and KINDL have versions to include younger children, but evidence for their psychometric robustness is weaker. The CHU-9D emerged as the PBM that has been evaluated more extensively, with some limited evidence in favour. However, the CHU-9D has not been tested with children and young people affected by neurodisability.
The fact that some newer PROMs have been subjected to greater methodological scrutiny, and thus more robust psychometric evidence, probably reflects the emerging awareness of higher standards required for scale development and methods for psychometric evaluation. The ability of developers of PROMs to fund research generally drives evaluation of the instruments. Hence, the lack of robust evidence for some older measures may be an artefact of the research process rather than mean that some scales perform poorly per se. Some older PROMs have become more established by frequency of use in research, even though robust psychometric evidence is lacking. Nevertheless, one can only make decisions based on the available evidence. There remains much scope for research to evaluate generic PROMs, particularly testing item invariance across neurodisability conditions, and responsiveness of PROM scores to meaningful change.
The selection of any instrument should be consistent with the purpose of measurement and psychometric properties; nevertheless, the questionnaire must have face validity to potential respondents. There appears only partial overlap between the suite of key outcomes identified by young people, parents and
professionals, and the content assessed by more competitive candidate PROMs. Looking broadly at WHO ICF-CY domains, each of these PROMs appears to assess some aspects prioritised; notably, though, communication is not represented in any of these PROMs, and mobility is tainted by a focus on
walking/running rather than‘moving around’, which, if more broadly conceived, would include use of assistive technology.
We presented examples of four commonly used PROM questionnaires as part of the qualitative research. General feedback on the questionnaires suggested poor face validity for using these to measure NHS care. Even though many questions were felt to be relevant, other key outcomes were identified as missing. In addition, participants disliked questions that were perceived as negatively phrased, verifying what colleagues had previously proposed.17Response options were not perceived to re
flect the health of children and young people affected by neurodisability appropriately, nor were they perceived likely to capture salient improvement or deterioration. The exemplar questionnaires we used were chosen as more commonly used instruments, and feedback may not reflect across all PROMs. Nor did we seek specific feedback on the PROMs individually, as they were simply conversation aids.
Careful cognitive interviewing should be undertaken with children, young people and parents to examine the face validity of any candidate instruments before selecting any PROMs. Key issues to consider are the content assessed, appropriate phrasing of questions, whether or not the proffered response options are likely to capture differences or changes in health that are meaningful and realistic for the population being studied, and length of questionnaire. Our qualitative research identified that some questions present cognitive challenges that young people and parents felt made responding difficult. Scale developers could do more work to ensure that such problems do not present, and those considering using PROMs in research or other contexts may want to pilot specific questionnaires for themselves.
Parents identified discomfort in being able to respond to some questions as their child’s proxy, particularly about emotional domains and about activities that take place away from them, such as at school and with friends. Hence, there may be consideration as to whether or not these questions should be asked of parents, especially as ample evidence identified in this review suggests strongly that proxy reporting is statistically unreliable. Parents may be required to report on behalf of those children who do not have the cognitive capacity to respond, but the questions parents are asked should reflect issues about which they feel able to respond. There were some outcomes that parents felt were more important to assess than did children and young people, including toileting, behaviour and safety, probably reflecting their roles as carers. These may be important outcomes to include in‘parent’reported instruments, but less relevant to include in self-reported questionnaires for children and young people.
SYNTHESIS OF FINDINGS
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