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Schematic of Prior Event Rate Ratio method for our case study. SU group are equivalent to the “Unexposed” group and TZD to the “exposed” group in the standard definitions of the PERR methodology. Time between start MFN and start SU/TZD is a maximum of 5 y. Pre-exposure and follow-up periods are up to 2 y. Abbreviations: SU, sulfonylurea; TZD, thiazolidinedione; MFN, metformin; PERR, Prior Event Rate Ratio.
