Hematocrit elevation after SGLT2 inhibitor administration may be associated with the degree of proximal tubular damage.

The renal protective effects of SGLT2 inhibitors are known to be due to the elimination of glomerular hypertension and improvement of hypoxia and oxidative stress in the proximal tubule. Therefore, this increased hematocrit (ΔHct) level has been hypothesized to indicate restored tubular function and improved renal prognosis. To analyze the relationship between ΔHct and decreased estimated glomerular filtration rate (eGFR) after SGLT2 inhibitor administration backward from medical record data. Data from 206 patients who continued SGLT2 inhibitors for >3 years were analyzed. The decreased eGFR after administration of SGLT2 inhibitors was defined as Slope B. Factors statistically significantly associated with Slope B in multiple regression analysis were systolic blood pressure (sBP) (β -.211, P = .03), short-term decreased eGFR after SGLT2 inhibitor administration (initial dip) (β -.235, P = .003), ΔHct (β -.185, P = .026), and urine protein (β -.204, P = .015). These findings were the opposite of our hypothesis. ΔHct was not a marker indicating improved renal prognosis and may reflect the extent of the proximal tubular disorder before administering SGLT2 inhibitors.