Objectives: To design and validate a scale to evaluate preferences of type 2 diabetic patients towards nutritional supplements (Madrid scale) and to discover those taste attributes that are more discriminating.
Context: ambulatory patients with type 2 diabetes mellitus.
Materials and methods: 18 controls and 106 type 2 diabetic patients received 2 of the 7 stimuli studied (6 nutritional supplements and a differential salty stimulus) and then completed both scales and a criterion question. Two weeks later, 30 diabetic patients received a retest. The psychometric properties of the Madrid scale were studied and the relative importance of each stimuli attribute was assessed.
Results: Feasibility: The Madrid scale consists of 8 questions and is completed in less than five minutes; Dimensionality: A single dimension which explains 45.1% of the variance. Reliability: Cronbach's , 0.806; intraclass correlation coefficient, 0.835 (95% confidence interval: 0.653-0.922). Concurrent validity: Correlation indexes of the corrected total score with the criterion question and the Modified Wine-Tasting Scale, 0.731 (p < 0.0005) and 0.774 (p < 0.0005), respectively. The scale discriminated between subjects younger and older than 75 years and between supplements and the differential stimulus. Preferences: Glucerna SR chocolate, Glucerna SR strawberry, Glucerna SR vanilla, Diasip vanilla, Clinutren vanilla and Resource diabet vanilla.
Conclusion: The Madrid scale has adequate psychometric properties for its use in research and daily clinical practice.