Anemia and anemia correction: surrogate markers or causes of morbidity in chronic kidney disease?

In this Review, Nosratola Vaziri endeavors to reconcile two apparently conflicting sets of evidence from patients with chronic kidney disease: the observational association between greater severity of anemia and increased risk of poor outcomes, and the increased risk of adverse outcomes in patients assigned to normal, rather than subnormal, hemoglobin targets in randomized clinical trials. The author focuses on data from basic and translational studies, which are often overlooked in the design and interpretation of clinical studies and in the formulation of clinical guidelines.