Development and content validity of a questionnaire to assess knowledge about delirium

Background Delirium is a neuropsychiatric syndrome that can have serious consequences and is often overlooked by healthcare professionals. The level of knowledge about delirium is often insufficient among nursing and medical staff. At the current time there is no suitable questionnaire to record the level of knowledge in German-speaking countries. Aim Development of a questionnaire and evaluation of content validity. Methods Following a literature search to identify current best practice, several questionnaires were identified. An already published questionnaire with the dimensions of basic knowledge of delirium and risk factors has been translated, adapted and extended by the dimension of nonpharmacological delirium prevention. Delirium experts assessed the relevance of the questionnaire items in two rounds of reviews. Content validity was calculated using the Content Validity Index (CVI) at item (I-CVI) and scale (S-CVI) level. Additionally, the modified Kappa (k*) was calculated using a lower 95% confidence interval (CI). Results The original 30-item questionnaire was expanded to include 18 delirium prevention items. After the first round of scoring 30 out of 48 items showed good to excellent I-CVI scores. Considering the comments, 6 items were discarded and 12 were adapted in terms of language and content. In the final version of the questionnaire 41 items with excellent scores remained. The total scale score increased from 0.88 in the first version to 1.0 in the final version. Nurses were identified as the target group, potentially also therapists and medical personnel. Conclusion The delirium knowledge questionnaire is content-valid.