Diabetes incidence in subjects with PREDIABetes from ReUNion Island: the PREDIABRUN observational cohort study protocol

Introduction: Improved knowledge of prediabetic subjects' profile and their risk of developing type 2 diabetes mellitus (T2DM) would enhance secondary prevention. The primary objective is to describe factors associated with incident T2DM in subjects with pre-diabetes diagnosed in primary care.

Methods and analysis: The study is based on Reunion Island, a French overseas region that experiences a particularly high disease burden of T2DM. This is an observational, non-randomised prospective cohort study conducted in primary care in which private general practitioner (GP) investigators recruit participants with pre-diabetes from their practices regardless of the initial motive for consultation. Pre-diabetes is defined by WHO criteria, that is, fasting plasma glucose between 1.10 g/L and 1.25 g/L and/or plasma glucose 2 hours after ingestion of 75 g of glucose (2-hour post load plasma glucose) between 1.40 g/L and 1.99 g/L. The design is based on an annual follow-up by the GP (according to French National Health Authority recommendations) with collection of clinical and laboratory data and specific lifestyle questionnaires answered by telephone at three time points: inclusion, and at 2-year and 5-year follow-up visits. Follow-up clinical and laboratory data are collected by the investigating GP as part of the study, and study-specific laboratory collections (serum, DNA and urine) will be obtained 2 and 5 years after inclusion. The primary outcome is transition to T2DM.

Ethics and dissemination: This protocol has been approved by the research ethics committee of Saint Etienne (CPP Saint Etienne reference number: 2019-03). Enrolment began in August 2019. Results will be disseminated in at least three papers published in peer-reviewed medical journals, one oral communication and a large-scale communication to the local population and healthcare policymakers.

Trial registration number: NCT04463160 and ID-RCB 2018-A03106-49.