RESUMEN
Purpose: To describe the processes of developing domains and items for the MultiMorbidity Questionnaire (MMQ), a multimorbidity-specific PROM for the assessment of Needs-based QoL. Patients and Methods: We developed items and domains for the MMQ through 17 qualitative content validity questionnaire interviews with adults with multimorbidity by testing items from an item bank (covering items with content inspired by existing Needs-based QoL measures for single diseases). The interviews alternated between an explorative part and more focused cognitive interview techniques. Results: Testing the 47 items from the first draft of the MMQ items showed that the Needs-based approach as a framework did not cover all the QoL aspects our informants stated as being important. Therefore, the conceptual framework was supplemented by Self-perceived health inequity, and new items were generated. MMQ, measuring Needs-based QoL (MMQ1) and Self-perceived health inequity (MMQ2), was assembled. MMQ1 covers the domains: "Physical ability" (10 items), "Limitations in everyday life" (15 items), "Worries" (11 items), "My social life" (11 items), "Self-image" (12 items), and "Personal finances" (2 items). Self-perceived health inequity proved to be a relevant framework for other aspects of QoL not covered by the Needs-based approach to QoL. MMQ2 covers the domains: "Experiences of being stigmatized" (five items), "Experiences of not being seen and heard" (four items), "Insufficient understanding of the burden of disease" (three items) and "Experiences of feeling powerless" (five items). Conclusion: We have developed the final MMQ draft, a multimorbidity-specific PROM for the assessment of Needs-based QoL (MMQ1) and Self-perceived health inequity (MMQ2) with high content validity (regarding content relevance and comprehensiveness). The final MMQ draft will be assessed for its psychometric properties using Modern Test Theory.
RESUMEN
PURPOSE: The aim of this study is to search systematically for Patient Reported Outcome Measures (PROMs) used among patients with multimorbidity. Furthermore, the aim is to evaluate the adequacy and validity of the PROMs identified. DESIGN AND SETTING: This systematic review follows the PRISMA guidelines. To assess the adequacy and validity of the identified PROMs the COSMIN Risk of Bias Checklist is used, more specifically a validation of the development, content validity, structural validity, and internal consistency of the PROMs. RESULTS: Four PROMs were identified in the primary search, and one was found from references. The sixth PROM was published after the primary search. None of the identified PROMs were aimed specifically at measuring the quality of life in patients with multimorbidity. According to the checklist, the development process and content validity were rated "adequate" in only one measure and "invalid"/"doubtful"/"inadequate" in the rest of the measures. The structural validity of the measures was rated "adequate" in four measures and "very good" in one. Regarding the internal consistency, two measures were rated doubtful and three "very good". None of the six PROMs reported analyses about invariant measurement. The COSMIN Risk of Bias Checklist proved easy to use; however, there are some concerns in the rating of bias, that are discussed further. CONCLUSION: All six PROMs developed for patients with multimorbidity identified possessed inadequacy in their measurement properties. Therefore, the aim for the future is to develop a valid and adequate measure of the quality of life among patients with multimorbidity.