Wang Y, et al. - Participants enrolled in the Mayo component of the Molecular Epidemiology Resource cohort study between 2002 and 2015 were examined to determine any possible impact of metformin on outcomes of newly diagnosed diffuse large B-cell (n = 869) and follicular lymphoma (n = 895) patients. The link between metformin exposure (No diabetes mellitus (DM)/No metformin; DM/No metformin; DM/Metformin) and outcomes (event-free, lymphoma-specific and overall survival) was estimated by using hazard ratios and 95% confidence intervals adjusted for age, sex, body mass index, prognostic index and treatment. No improved outcomes were evident in these cases in relation to metformin use.