Cirillo M, et al. - Correlates and prognostic power of indices of osmotic equilibrium and of kidney concentrating activity (KCA) were investigated in a sample of the general population. Independent association of sex, age, obesity, estimated glomerular filtration rate (eGFR), urine flow, hypertension and smoking with urine osmolality (U-osm) and KCA was noted. In addition, U-osm and KCA independently predicted mortality, but not kidney function change over time.