Transtheoretical model-based dietary interventions in primary care: a review of the evidence in diabetes

The objective of this study was to review the evidence concerning stage-based dietary interventions in primary care among persons with diabetes or an elevated diabetes risk. Search strategies were electronic databases and manual search. Selection criteria were randomized controlled studies with stage-based dietary intervention, conducted in primary care with at least 6 months of follow-up, and participants with either type 2 diabetes or with an elevated risk. The researchers evaluated trials for inclusion, extracted data and assessed study quality. Seven articles, based on five data sets, were included. These studies concentrated on cardiovascular diseases and being overweight, not diabetes. The quality of the studies was moderate to weak. Inadequacies in the reporting often involved unspecific information on the training of health care providers. Long-term positive outcomes (compared with controls) were found in total and monounsaturated fat intake, diastolic blood pressure, health status and well-being. The existing data are insufficient for drawing conclusions on the benefits of the transtheoretical model. More high-quality studies focusing on diabetes are needed, with greater attention to the training of providers and process evaluation. There is a need for a standardized appraisal tool for study evaluation, focusing separately on education interventions for patients and providers.