Randomized Trial Comparing SGLT2 Inhibition and Hydrochlorothiazide on Sympathetic Traffic in Type 2 Diabetes.

INTRODUCTION: Reductions in sympathetic nervous system activity may contribute to beneficial effects of sodium glucose cotransporter 2 (SGLT2) inhibition on cardiovascular outcomes. Therefore, we tested the hypothesis that SGLT2 inhibition with empagliflozin (Empa) lowers muscle sympathetic nerve activity (MSNA) in patients with type 2 diabetes mellitus (T2DM) compared with hydrochlorothiazide (HCT) to discern SGLT2-specific actions from responses to increased natriuresis.

METHODS: We randomized patients with T2DM on metformin monotherapy to either 25 mg/d Empa ( n  = 20) or 25 mg/d HCT ( n  = 21) for 6 weeks in a parallel, double-blind fashion. We assessed MSNA by peroneal microneurography, blood pressure, cardiovascular and metabolic biomarkers at baseline and at the end of treatment.

RESULTS: Both drugs elicited volume depletion, as indicated by increased thoracic impedance. Compared with HCT, Empa caused 1.23 kg more body weight loss ( P  = 0.011) and improved glycemic control. Seated systolic blood pressure decreased with both treatments ( P  < 0.002). MSNA did not change significantly with either treatment; however, MSNA changes were negatively correlated with changes in body weight on Empa ( P  = 0.042) and on HCT( P  = 0.001). The relationship was shifted to lower MSNA on Empa compared with HCT ( P  = 0.002).

CONCLUSION: Increased renal sodium excretion eliciting body weight loss may promote sympathetic activation. However, sympathetic excitation in the face of increased sodium loss may be attenuated by SGLT2 inhibitor-specific actions.