We often stop metformin when eGFR < 30 (CKD stage 4). In this observational study of 4,278 patients with type 2 diabetes and CKD stage 4, stopping metformin (40.1% of patients) was associated with lower 3-year survival (63.7% vs 70.5%). Time for an RCT? #MedSky #NephSky https://www.ajkd.org/article/S0272-6386(24)01041-2/fulltext