Osmotic nephropathy triggered by sodium-glucose cotransporter 2 inhibitors in a patient with IgA nephropathy.

A woman with biopsy-confirmed IgA nephropathy (IgAN) presented with persistent non-nephrotic range proteinuria and stage 3b chronic kidney disease (CKD). Her treatment regimen included the initiation of a sodium-glucose cotransporter 2 inhibitor (SGLT2i), dapagliflozin, starting at 5 mg daily and later titrated to 10 mg daily after several months. Following the dose increase, she developed significant acute-on-chronic kidney injury. Despite discontinuing the SGLT2i, her renal function did not recover. A subsequent kidney biopsy revealed findings consistent with osmotic tubulopathy with worsening IgAN. This case highlights a rare but important adverse effect of SGLT2i, particularly in patients with pre-existing CKD. While initial expert guidance advised against routine renal function monitoring to avoid premature discontinuation due to the expected transient rise in creatinine, evolving clinical experience suggests that individualised monitoring may be necessary in high-risk patients. Future guidelines will need to clarify how to balance these considerations to optimise patient outcomes.