Development and validation of the Diabetes Medication System Rating Questionnaire-Short Form

Abstract

Aims: To develop and validate a short form of the 54-item Diabetes Medication System Rating Questionnaire that maintains the domains and performance characteristics of the long-form questionnaire.

Methods: Data from the Diabetes Medication System Rating Questionnaire validation study were analysed to select items representing the nine scales (convenience, negative events, interference, self-monitoring of blood glucose burden, efficacy, social burden, psychological well-being, treatment satisfaction and treatment preference). The resulting 20-item Diabetes Medication System Rating Questionnaire Short-Form was administered online, with validated criterion measures of treatment satisfaction and medication adherence, with a retest within 2 weeks. Participants were US adults (N = 413) with Type 2 diabetes using oral agents alone; insulin by syringe and/or pen with or without oral agents; or glucagon-like peptide-1 agents. Most participants (82%) completed the retest.

Results: The median inter-item agreement of scales was 0.76 and the total composite (mean of all items except treatment preference) was 0.88. The median test-retest reliability of scales was 0.86, and of the total composite was 0.95. All statistically significant correlations between Diabetes Medication System Rating Questionnaire Short-Form scales and criterion measures of treatment satisfaction and adherence were in the expected direction. The median correlation of the Diabetes Medication System Rating Questionnaire Short-Form with corresponding criterion measures of treatment satisfaction was 0.59; the mean correlation of the same Diabetes Medication System Rating Questionnaire Short-Form measures with adherence was 0.42. The Diabetes Medication System Rating Questionnaire Short-Form scales were more powerful predictors of adherence than were the criterion measures of treatment satisfaction. The Diabetes Medication System Rating Questionnaire Short-Form scales differentiated between those taking different medications and between those using different insulin delivery devices.

Conclusions: This study suggests that the Diabetes Medication System Rating Questionnaire Short-Form provides a comprehensive set of measures with acceptable reliability and validity and a reduced burden of administration.