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 (χ2 = 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.