Flow chart. Flow chart of the numbers of questionnaires sent, the number of questionnaires returned and the number of individual questions answered. Baseline characteristics were calculated i) for patients who returned the questionnaire, ii) for patients who did not return the questionnaire and iii) for patients who returned the questionnaire and who completely filled out all questions. The latter correspond to the patients included in the analysis comparing both response scales. NS = Numeric Scale, LS = Labelled Scale. NA refers to not applicable as answering option in the two questions about comprehensibility of the answers from physicians and nurses. In this case NA means the patient did not have had any questions.