Rationale and design of the EMPYREAN study.

Aims A sodium glucose cotransporter 2 (SGLT2) inhibitor was recently found to reduce heart failure hospitalization in the EMPA-REG OUTCOME trial. We have hypothesized that autonomic nerve activity may be modulated by SGLT2 inhibition. The current study aims to investigate the impact of empagliflozin on sympathetic and parasympathetic nerve activity in patients with type 2 diabetes mellitus. Methods and results This ongoing study is a prospective, randomized, open-label, multicentre investigation of 134 patients with type 2 diabetes mellitus. The patients are randomly allocated to receive either empagliflozin or sitagliptin with the treatment goal of the Japan Diabetes Society guidelines. Ambulatory electrocardiographic monitoring is performed at the baseline and at 12 and 24 weeks of treatment. Analyses of heart rate variability are conducted using the MemCalc method, which is a combination of the maximum entropy method for spectral analysis and the non-linear least squares method for square analysis. The primary endpoint is the change in the low-frequency (0.04-0.15 Hz)/high-frequency (0.15-0.4 Hz) ratio from baseline to 24 weeks. Conclusions This investigation on the effect of EMPagliflozin on cardiac sYmpathetic and parasympathetic neRve activity in JapanEse pAtieNts with type 2 diabetes (EMPYREAN study) offers an important opportunity to understand the impact of SGLT2 inhibition on autonomic nerve activity in patients with type 2 diabetes.