Validation of an instrument to measure adherence to type 2 diabetes management

Background Adherence to type 2 diabetes management is defined as the extent to which the behaviour of a person matches the one recommended by health care professionals. Control of this disease depends on adherence to diabetes management, which includes monitoring blood glucose levels, adopting a healthy diet, exercising, taking medication, quitting smoking, and undergoing psychosocial care and periodic check-ups. This can also prevent health complications and reduce medical costs. Objective The objective of this study is to validate a culturally appropriate instrument directed towards the Mexican population that measures a patient's level of adherence to their type 2 diabetes mellitus management. Method The study design was cross-sectional. The instrument was applied individually (face to face researcher-assisted survey) by a member of the team. The study sample included 200 participants, which were attended at an outpatient clinic. To evaluate the psychometric validity of the scale we calculated response frequencies, the discrimination of items for extreme groups, the validity, and the internal reliability. The scale of adherence for complete management in patients with type 2 diabetes includes disease monitoring, complication prevention, and social support using questions and answers based on the Likert scale, corresponding to the 5 stages of the transtheoretical model. Main outcome measure The validity and internal reliability of the instrument to measure adherence to type 2 diabetes management, which proved to be justifiable and reliable with a Cronbach's alpha of 0.92 and a total explained variance of 65.03%. Results The instrument was composed of 29 items and 6 factors: adherence to medical Cronbach's alpha = 0.92 and dietary treatment Cronbach's alpha = 0.88, change in dietary habits Cronbach's alpha = 0.89, adherence to physical activity and exercise Cronbach's alpha = 0.84, social support Cronbach's alpha = 0.79, and prevention of complications Cronbach's alpha = 0.70. The instrument obtained a content validity index (I-CVI) of 0.9. Conclusion The proposed instrument, which includes factors that measure adherence in type 2 diabetes mellitus patient's management, using the transtheoretical model of behaviour change to simultaneously identify patient motivation to change their lifestyle, is valid and reliable.