Social Prescription of Health Assets and Lifestyles Modification by Primary Care Nurses to Reduce Glycemia in People With Prediabetes: PREDIBAL Study -a Cluster-randomized Hybrid Effectiveness-implementation Type II Trial Protocol

No pragmatic clinical trial evaluating the effectiveness of prevention interventions has been performed to date. Social prescription is a useful health promotion strategy that facilitates the continuity of individual care. This randomized controlled trial aims to evaluate the effectiveness and cost-utility of an intervention based on the social prescription of health assets to modify lifestyles and reduce blood glucose values in prediabetic patients in primary care nursing consultations. Additional aims are to describe and assess barriers, motivations, and attitudes of patients with low adherence to the intervention and their association with social class and gender.

Methods: Multicentre, controlled and randomized (two different branches) clinical trial with 18 months of follow-up will be performed. The randomization unit will be the primary healthcare center. The study will be conducted by nurses in 12 primary health care centers (PHC) of Mallorca in Spain that will be included and randomly allocated to intervention or control groups. Furthermore, the intervention will be delivered at the PHC level, which is considered the unit of analysis. At least 232 patients (116 per branch) will be recruited. Participants will be aged 25 to 75 years with altered fasting glucose levels (100-125 mg/dl) or with glycosylated hemoglobin (HbA1c) between 5.7 and 6.4%. The intervention will be carried out at three levels: community, group and individually. The intervention group will receive a social prescription of health assets related to the practice of physical activity and healthy eating patterns in primary care nursing consultation for 8 sessions during 12 months of follow-up. The Control group will follow the usual care recommendations. Data will be collected at baseline, 6, 12 and 18 months. Glycaemia, HbA1c, BMI and waist circumference will be measured, as well as the Mediterranean diet adherence (PREDIMED), the physical activity (IPAQ), the cardiovascular risk (REGICOR equation), the quality of life (EuroQoL-5D), the social class, gender, and financial costs.

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