Validation of a new tool for evaluating subjects' satisfaction with medicine package leaflets: a cross-sectional descriptive study

ABSTRACT

ABSTRACT BACKGROUND: Package leaflets of medicines need to be intelligible, but tools for their evaluation are scarce. OBJECTIVE: To validate a new tool for assessing subjects' satisfaction with medicine package leaflets (LiS-RPL). DESIGN AND SETTING: Cross-sectional descriptive study conducted in two regions of Portugal (Lisbon and Centre). METHODS: 503 participants (53.1% male) were selected according to convenience and homogenously distributed into three groups 1 to 6; 7 to 12; and > 12 years of schooling. LiS-RPL was developed based on international regulation guidelines and was initially composed of 14 items. Twelve package leaflets were tested. Dimensionality calculations included exploratory factor analysis and minimum rank factor analysis; Kaiser-Meyer-Olkin index and Bartlett's sphericity test to assess matrix adequacy for exploratory factor analysis; exploratory bifactor analysis with Schmid-Leiman solution to detect possible existence of a broad second-order factor; and Bentler's Simplicity Index and Loading Simplicity Index to assess factor simplicity. Diverse coefficients were calculated to assess reliability. RESULTS: Minimum rank factor analysis detected a two-factor or single-factor structure. Exploratory factor analysis with 12 items showed a two-factor structure, explaining 69.11% of the variance. These items were strongly correlated with each other (r = 0.80). Schmid-Leiman all items seemed to represent the general factor (loadings above 0.50), which was 76.4% of the extracted variance. Simplicity indices were good (percentile 99) Bentler's Simplicity Index of 0.99 and Loading Simplicity Index of 0.48. Internal consistency indexes indicated good reliability. LiS-RPL was shown to be homogenous. CONCLUSION: LiS-RPL is a validated tool for evaluating subjects' satisfaction with medicine package leaflets.