SPP1 and acute kidney injury: The prospective study with 102 ICU patients with AKI-D by Yang et al. aimed to explore the prognostic value of several biomarkers (serum osteopontin, interleukin 6, interleukin 18, cystatin C and serum NGAL; urinary NGAL and interleukin 18) measured upon discontinuation of RRT for their value in predicting 60-day survival and renal recovery [36].