FGF23 and chronic kidney disease: In support of these experimental data, an increasing number of observational studies have shown high FGF23 levels to be associated with death across the spectrum of CKD, including patients with non–dialysis-dependent CKD,15, 16, 17, 18, 19, 20 patients with incident hemodialysis,21,22 recipients of kidney transplants,23,24 and individuals with apparently normal kidney function.25, 26, 27, 28, 29, 30, 31, 32 However, the relationship between FGF23 and death among prevalent hemodialysis patients have been examined only in small studies33, 34, 35, 36 and few large-scale studies.37