Cognitive interviewing study to assess the content validity of a Spanish version of the Multiple Sclerosis Health Literacy Questionnaire.

Objectives: To develop a Spanish version of the Multiple Sclerosis Health Literacy Questionnaire (MSHLQ) and assess its content validity from the perspective of people with multiple sclerosis (MS).

Study Design: Cognitive interviewing study.

Methods: We used a step-by-step process to translate the MSHLQ into Spanish and employed purposive sampling to achieve a representative sample of the target population. We invited people aged 18 and older with MS who are users of a public healthcare service to participate. We carried out two rounds of interviews, both conducted by the same skilled interviewer. Two coders independently assessed the interview transcriptions using the Question Appraisal System.

Results: Thirteen interviews were analysed in the first round, reaching saturation. The sample comprised people with MS, with a balanced gender distribution and varied educational backgrounds, and with MS diagnosis durations ranging from 1 to 24 years. Problematic issues found in the pre-final MSHLQ-SPA included 15 out of 22 items. We identified 45 clarity issues and 23 assumption-related problems, plus two overlapping responses. After amendments, only five issues were found in the second round.

Conclusions: Over two-thirds of items in the pre-final MSHLQ-SPA version had problematic issues, mostly clarity-related. This study contributes to the body of evidence regarding MSHLQ content validity, an essential instrument property for ensuring its accurate interpretation and use across different countries or contexts. Tailored health literacy measurement instruments for people with MS have the potential to improve health outcomes and reduce health inequalities.