[Prevention of type 2 diabetes mellitus in primary care: the APHRODITE study]

OBJECTIVE: To determine the effectiveness of a 2.5-year lifestyle intervention aimed at preventing type 2 diabetes mellitus (DM2) in Dutch general practice (the APHRODITE study). DESIGN: Randomized controlled trial (NTR1082). METHODS: Based on a validated questionnaire, individuals from 14 general practices who were found to be at high risk for DM2 were randomized into either an intervention group (n = 479) or a standard-care (reference) group (n = 446). The interventions consisted of lifestyle counselling by the general practitioner and a nurse practitioner as well as group consultations. The standard-care group received verbal and written information at the start of the study. After 2.5 years, the incidence of DM2 and other clinical outcome measures from both groups were compared. RESULTS: The outcomes of both groups showed modest changes in body weight (weight (SD): intervention group: -0.8 (5.1) kg; reference group: -0.4 (4.7) kg; p = 0.69) and in glucose concentrations (fasting glucose levels (SD): intervention group: -0.17 (0.4) mmol/l; reference group: -0.10 (0.5) mmol/l; p = 0.10). No statistically significant differences between groups were found in clinical outcome measures or in the incidence of DM2. In the intervention group, the participants' level of trust in their own competence (self-efficacy) was significantly higher in individuals who had lost more than 2% body weight compared with those who had lost less than 2%. No statistically significant differences in weight loss were found between participants counselled by general practitioners or nurse practitioners with different levels of motivation, confidence in lifestyle interventions in general practice or self-efficacy regarding nutritional and physical activity counselling. CONCLUSIONS: Risk factors for DM2 could significantly be reduced in Dutch general practise. However, the effectiveness of the lifestyle intervention was modest; implementation of the programme in its current form is therefore not advisable. Adaptation or refinement of the delivery and content of the intervention is necessary to increase its effectiveness