Erratum to: Rationale and design of oBservational clinical Research In chronic kidney disease patients with renal anemia: renal proGnosis in patients with Hyporesponsive anemia To Erythropoiesis-stimulating agents, darbepoetiN alfa (BRIGHTEN Trial) (Clinical and Experimental Nephrology, (2018), 22, 1, (78-84), 10.1007/s10157-017-1427-4)