Psychometric properties of questionnaire-based measurement of immunosuppressant knowledge in kidney transplantation: a scoping review

Questionnaires are often used to evaluate the understanding of immunosuppressive therapy (IST) among kidney transplant recipients (KTR). This study investigated the psychometric properties of these questionnaires and their level of recommendation for use. Relevant articles were searched from PubMed, MEDLINE, CINAHL, Web of Science, Cochrane Library, and Scopus utilising the PRISMA Extension for Scoping Review protocol. Peer-reviewed and English-language articles that reported on the psychometric properties of questionnaires evaluating IST knowledge among KTR were considered relevant. The Consensus-based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines and the TERWEE tool were used to evaluate psychometrics for methodological quality, criteria for good measurement, level of evidence (LoE), and applicability. Of the 88 potential articles, 10 were deemed relevant. The articles comprised cross-sectional studies (n=7), tool validation studies (n=2), and studies that combined both methods (n=1). Content validity was described in 8 articles and presented as ‘doubtful’ in all of them; internal consistency in 8 articles and rated ‘very good’ (n=6) and ‘doubtful’ (n=2); structural validity in 2 and both were rated ‘adequate’; reliability in 4 and rated ‘very good’ (n=2) and ‘doubtful (n=2), hypothesis testing in 3 with ‘very good (n=2) and ‘adequate’ (n=1) ratings; and responsiveness in one article rated as ‘adequate. The criteria for most properties were classified between 'indeterminate' and ‘adequate’; with a ‘moderate LoE.’ All questionnaires received grade B recommendations. Existing questionnaires lack validity and reliability, necessitating future research to develop questionnaires with appropriate constructs to accurately assess knowledge about IST among KTR.