Effects of a Mediterranean Eating Plan on the Need for Glucose-Lowering Medications in Participants With Type 2 Diabetes: A Subgroup Analysis of the PREDIMED Trial

F. Javier Basterra-Gortari, Miguel Ruiz-Canela, Miguel A. Martínez-González, Nancy Babio, José V. Sorlí, Montserrat Fito, Emilio Ros, Enrique Gómez-Gracia, Miquel Fiol, José Lapetra, Ramón Estruch, Luis Serra-Majem, Xavier Pinto, José I. González, Mónica Bulló, Olga Castañer, Ángel Alonso-Gómez, Luis Forga, Fernando Arós

To examine the effects of two Mediterranean eating plans (Med-EatPlans) versus a low-fat eating plan on the need for glucose-lowering medications. From the PREDIMED trial, we selected 3,230 participants with type 2 diabetes at baseline. These participants were randomly assigned to one of three eating plans: Med-EatPlan supplemented with extra virgin olive oil (EVOO), Med-EatPlan supplemented with mixed nuts, or a low-fat eating plan (control). In a subgroup (15%), the allocation was done in small clusters instead of using individual randomization, and the clustering effect was taken into account in the statistical analysis. In multivariable time-to-event survival models, we assessed two outcomes: 1) introduction of the first glucose-lowering medication (oral or injectable) among participants on lifestyle management at enrollment and 2) insulin initiation. After a median follow-up of 3.2 years, in multivariable analyses adjusting for baseline characteristics and propensity scores, the hazard ratios (HRs) of starting a first glucose-lowering medication were 0.78 (95% CI 0.62-0.98) for Med-EatPlan + EVOO and 0.89 (0.71-1.12) for Med-EatPlan + nuts, compared with the control eating plan. After a median follow-up of 5.1 years, the adjusted HRs of starting insulin treatment were 0.87 (0.68-1.11) for Med-EatPlan + EVOO and 0.89 (0.69-1.14) for Med-EatPlan + nuts compared with the control eating plan. Among participants with type 2 diabetes, a Med-EatPlan + EVOO may delay the introduction of new-onset glucose-lowering medications. The Med-EatPlan did not result in a significantly lower need for insulin.