The network of psychological variables in patients with diabetes and their importance for quality of life and metabolic control

Abstract

OBJECTIVE - The primary goals in treating patients with diabetes are maintaining blood glucose levels as close to normal as possible and making a relatively normal quality of life achievable. Both of these goals are influenced by a multitude of somatic and psychological factors that should be seen as building a complex network. We examined whether a mathematical model can be construed that can depict the relative significance of each factor for achieving these treatment goals. RESEARCH DESIGN AND METHODS - A total of 625 patients from 32 different treatment facilities were examined (224 type 1 and 401 type 2 diabetic patients) using HbA1c values (high-performance liquid chromatography), number of secondary illnesses, and standardized questionnaires with respect to health-related quality of life (World Health Organization Quality of Life questionnaire), coping behavior (Freiburger Illness-Coping Strategies questionnaire), diabetes-specific knowledge (Test of Diabetes-Specific Knowledge), doctor-patient relationship (Medical Interview Satisfaction Scale), and personality characteristics (Giessen Test and Assessment of Beliefs in Self-Efficacy and Optimism). The analyses were carried out by means of a structural equation model. RESULTS - The model proved to be valid (x2 = 88.5, df = 76, P = 0.16), showing a sound fit (adjusted goodness of fit [AGFI] = 0.94). It explained 62% of the variance of the quality of life and 5% of the HbA1c values. Subjects characterized by strong beliefs in their self-efficacy and an optimistic outlook on life were more likely to be satisfied with their doctor-patient relationships. They demonstrated more active coping behavior and proved to have a higher quality of life. Active coping behavior was the only psychological variable significant for the HbA1c values. CONCLUSIONS - It was possible to illustrate the various factors involved and their mutual dependency and significance for the treatment goals. Belief in self-efficacy and active coping behavior appear to have the greatest relevance for achieving the primary treatment goals.