A compensatory elevation of circulating FGF21 was observed in patients with chronic kidney disease (CKD) and diabetic nephropathy in cross-sectional studies.[5] Longitudinal studies have suggested a predictive effect of higher levels of FGF21 on the decline of renal function or an increase in albuminuria in patients with T2D.[6–8] Conversely, in a longitudinal study of community-dwelling individuals without apparent cardiovascular disease, the predictive effect was not confirmed.[9]. This evidence concerns the gene FGF21 and type 2 diabetes mellitus.