Characteristics and Outcomes of IgA Nephropathy Patients With SGLT2 Inhibitor-Induced Polycythemia.

PURPOSE: Sodium-glucose co-transporter 2 (SGLT2) inhibitors provide renal and cardiovascular benefits in IgA nephropathy (IgAN). However, their hematopoietic effect can cause polycythemia in rare cases. We aimed to evaluate the clinical characteristics and two-year outcomes of patients with IgAN with SGLT2 inhibitor-induced polycythemia. METHODS: We retrospectively analyzed data of adult patients with IgAN treated with dapagliflozin (DAPA) at our department between 2021 and 2023. Patients were divided into two groups based on whether or not they developed polycythemia within 24 months of initiating DAPA therapy (those who developed polycythemia were in the polycythemia (P) group, and those who did not were in the normal (N) group). Clinical characteristics and cardio-renal outcomes were evaluated at baseline and three, six, 12, 18, and 24 months post-SGLT2 inhibitor initiation and compared between the groups. RESULTS: Of the 174 patients screened, 28 were included. Compared to the N group (n=18), the P group (n=10) had a higher proportion of men, dyslipidemia, and hyperuricemia, and higher body weight and higher red blood cell count at baseline. Polycythemia developed even in patients with high baseline hemoglobin (Hb) levels; however, these returned to baseline levels within two years. Systolic blood pressure and proteinuria levels decreased significantly over the two-year period in both groups, but the decrease was slower in the P group than in the N group. No cardiovascular events occurred in either group during the follow-up period. CONCLUSIONS: The SGLT2 inhibitor-induced polycythemia in patients with IgAN was transient and did not affect the two-year cardio-renal outcomes. Therefore, our findings suggest that continuing SGLT2 inhibitor therapy in these patients may be reasonable, as the condition appeared to be transient and did not adversely affect cardio-renal outcomes.