Gasparini A, et al. - Researchers formally evaluated the finding from small-scale studies suggesting hyperkalaemia is a less threatening condition in chronic kidney disease (CKD) by approximating the distribution of plasma K⁺ and its link with mortality across CKD stages. In this observational study, they included 831,760 participants undergoing plasma K⁺ testing in Stockholm during 2006-2011. Of these, 70,403 (8.5%) had CKD G3 (estimated glomerular filtration rate [eGFR] <60–30 mL/min) and 8,594 (1.1%) had CKD G4–G5 (eGFR <30 mL/min). Findings suggested a U-shaped association between K⁺ and mortality, which flattened at lower eGFR strata and shifted upwards. This suggests that CKD stage modifies K+ distribution and the ranges that predict mortality in the community. Findings thus challenge the current use of a single optimal K⁺ range for all patients.