Is there a practical way of predicting therapeutic success in type 2 diabetes on the basis of psychological features? Development and validation of the Psychological Predictors of Therapeutic success in Diabetes (PPTD) questionnaire

Many psychiatric disorders and symptoms have been associated with impaired metabolic control in type 2 diabetes; several studies focused on non-pathological psychological features. Aims of this observational, longitudinal study are: the assessment of the impact of a wide range of psychological factors on metabolic control in type 2 diabetes; and the development and validation of a simple questionnaire to assess the impact of psychological factors on therapeutic success. To identify psychological factors interfering with attainment of glycemic targets, a prospective 1-year study was performed on a sample of 250 patients with type 2 diabetes. The impact of identified factors on therapeutic outcome was then subsequently verified on a further, independent sample of 200 patients. The first phase of the study allowed the development of a 19-items questionnaire, the Psychological Predictors of Therapeutic success in Diabetes (PPTD) questionnaire. Validation analyses showed that the questionnaire was able to predict therapeutic success. Patients with HbA1c ≤7 % (53 mmol/mol) at follow-up showed higher test scores than those with HbA1c >7 % [31.0 (26.2; 35.0) vs 28.0 (23.0; 32.0); p = 0.016]. The attainment and maintenance of therapeutic goals in patients with type 2 diabetes depend on a wide range of factors. The PPTD is an attempt at condensing the complexity of psychological factors affecting glycemic control in a simple and easy-to-use self-reported questionnaire, which can be used in wide-scale research.