It is vital that patients understand the language used in leaflets in medicine packages and in information for participation in medical research. The aim of the study was to determine the proportion of Danes with reading skills corresponding to 9-10 years of schooling who understand the language used by health-care professionals in materials targeted at laypeople.
Based on a study of ordinary citizens' understanding of the language used in printed communication from Danish authorities we tested the words used in printed matters from the health-care system; specifically information forms and questionnaires from research protocols submitted to the local ethics committee. In addition 44 students from adult learning centres were asked to comment on their understanding of words via individual interviews about patient leaflets from medicine packages. In total 143 common words were selected and tested with 404 other students. A word would be considered difficult if less than 90% of the students understood its meaning.
Of the 143 words, 14 (10%) were understood correctly by less than 10% of the students, 33 (23%) by 10-25%, 46 (32%) by 25-50%, and 50 (35%) by more than half. No words were understood by 90% or more.
Ordinary words are difficult to understand when used in a medical context. Our study did not identify any rule or principle to predict which words laypeople understand. Consequently printed communications from the health-care system to laypeople must be pre-tested by end users to ensure comprehension.