Development, reliability, and validity of a new Preference and Satisfaction Questionnaire.

ABSTRACT

OBJECTIVES: Existing questionnaires that assess preference and/or satisfaction with postmenopausal bone loss treatments were reviewed and determined to be inadequate for the assessment of an oral pill versus a subcutaneous injection. The Preference and Satisfaction Questionnaire (PSQ) was developed to assess preference, satisfaction, and bother with a weekly oral tablet versus a once every 6 months subcutaneous injection for treatment of postmenopausal bone loss. METHODS: Questions were developed based on literature review and expert input. Content validity of the PSQ in this patient population was assessed among current or previous bisphosphonate users in group interviews, and item comprehension and readability were also evaluated. Reliability, validity, and structure of the questionnaire were assessed in two phase 3 randomized clinical trials. RESULTS: Twenty-four women participated in cognitive interviews and found the PSQ understandable and acceptable. Subsequently, 1583 trial participants took the PSQ. Interitem correlations, ranging from 0.50 to 0.97 for preference items, 0.85 to 0.94 for pill-satisfaction items, and 0.84 to 0.92 for injection-satisfaction items, and a well-fitting confirmatory factor analysis (root mean square error of approximation 0.04, nonnormed fit index 0.99, and root mean square residual 0.08) supported the structure of the instrument. Cronbach's alpha reliability values for pill satisfaction, injection satisfaction, pill bother, and injection bother were 0.93, 0.89, 0.82, and 0.61, respectively. Discriminative validity was indicated with better satisfaction and bother scores being related to adherence and the absence of adverse events. CONCLUSIONS: The PSQ is a valid and reliable measure and may be a valuable tool to assess patient preference and satisfaction with a weekly oral tablet and 6-month subcutaneous injection for postmenopausal bone loss.