Early effects of sodium-glucose co-transporter 2 inhibitors in type 2 diabetes: study based on continuous glucose monitoring

BACKGROUND Inhibitors of sodium-glucose co-transporter 2 (SGLT2) have immediate glucose-lowering effects by promoting urinary glucose excretion, without altering insulin level. Only a few studies have evaluated blood glucose dynamics in the early period after administration. The present retrospective study was designed to determine the immediate effects of SGLT2 inhibitors on blood glucose dynamics. METHODS The study subjects were 24 patients with type 2 diabetes whose blood glucose dynamics were evaluated with continuous glucose monitoring for 1 week before and after initiation of SGLT2 inhibitor therapy. Blood glucose dynamics were examined on days -1, 0 (treatment commencement day), 3, and 7 by evaluating different continuous glucose monitoring parameters and blood glucose before each meal. Furthermore, blood glucose levels at 1 and 2 h after each meal and daily urinary glucose levels were determined. RESULTS A significant reduction in blood glucose levels 2 h after breakfast was observed between the day before treatment (249.8 mg/dL) and the day treatment started (218.9 mg/dL). The mean daily blood glucose level improved significantly from 201.4 to 142.3 mg/dL from the day the treatment started. Blood glucose variation also improved significantly by week 1, as demonstrated by changes in standard deviation and mean amplitude of glycemic excursions (from 39.6 to 31.7 and 106.9 to 87.4 mg/dL, respectively). The percent time at blood glucose <70 mg/dL remained unchanged while urinary glucose on day 7 correlated with minimum blood glucose level (r = 0.474, p = 0.022). CONCLUSIONS The results showed that the SGLT2 inhibitors lower blood glucose from 2 h after the first dose and improve blood glucose variation by week 1 after start of the treatment. Furthermore, SGLT2 inhibitors did not alter the incidence of hypoglycemic episodes at week 1, suggesting that SGLT2 protects against severe hypoglycemia by inhibiting urinary glucose excretion.