Reduced EPO and haemoglobin levels can arise as interstitial EPO-synthesising cells transform to pro-inflammatory and -fibrotic myofibroblasts, a key step in the development of kidney interstitial fibrosis in CKD.16 17 Considering that anaemia has been associated with worse renal prognosis after AKI in this population8 and the role EPO-producing cells have in promoting interstitial fibrosis, reduced EPO synthesis points to kidney injury as an intermediary cause of anaemia and could also indicate a risk of progressive kidney disease. This evidence concerns the gene EPO and anemia (phenotype).