Reliability, validity and relevance of needs assessment instruments for informal dementia caregivers: a psychometric systematic review

The objective of this review was to identify reliable and/or valid needs assessment instruments for informal dementia caregivers that are relevant for clinical practice, research and informal caregivers.

Informal dementia caregivers report important unmet needs at all stages of the disease. In addition, they often indicate that health care providers insufficiently attend and adapt to their multiple needs. A systematic and patient-centered assessment is needed to address this lack of knowledge and understanding. However, existing quantitative needs assessment questionnaires are limited in terms of psychometric testing. Qualitative measures are time-intensive and difficult to conduct on a large scale, with growing economic pressure. Information about the methodological quality and the characteristics of needs assessment instruments are crucial for clinicians and researchers to make informed decisions about the most reliable and valid tool for their specific purpose.

This review considered studies on multidimensional needs assessment instruments for informal dementia caregivers living at home. Psychometric studies or other types of studies with sufficient data to evaluate methodological quality were included if they considered at least one outcome for reliability or validity.

Studies in English, French or German and published until February 2019 were searched in four databases: Embase, MEDLINE, CINAHL and PsycINFO. After screening the titles, abstracts or full texts for eligibility, the provisional included studies were assessed for methodological quality with a standardized tool for systematic reviews of measurement properties. After data extraction using a standardized tool, the quality of the measurement properties was rated and compared using predefined quality criteria.

Eighteen articles covering 14 different needs assessment instruments were included in the review. Eleven publications focused on the development or the evaluation of an instrument. In addition, a development report, a manual and five studies, not aimed primarily at validation but containing sufficient information about the development or the evaluation of the used instruments, were included. The systematic evaluation of the instruments revealed that half of them had excellent content validity. In contrast, structural validity was rarely examined, and mostly with an insufficient sample size or a questionable analysis. None of the instruments had optimally tested and good internal consistency. Regarding reliability, test-retest agreement was rarely tested and inter-rater agreement was evaluated using controversial procedures. Comparing the different instruments reviewed, the "Partnering for better health - living with chronic illness: dementia" had the best psychometric evidence, and the "Questionnaire of consultation expectations" was also partly supported, while most other instruments presently had limited psychometric soundness.

Despite the good evidence for some psychometric properties, further developments in the field of needs assessment for informal dementia caregivers are needed, particularly regarding structural and construct validity, as well as test-retest reliability and sensitivity to change. To enhance conceptual clarity, the development of an underlying theoretical model of needs should be prioritized.