Generating Items for Measuring Needs-Based Quality of Life and Self-Perceived Health Inequity in Patients with Multimorbidity: Development of the MultiMorbidity Questionnaire (MMQ).

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.