The normal hematocrit cardiac trial revisited.

Area of Science:

• Nephrology
• Cardiology
• Hematology

Background:

• Anemia is common in chronic kidney disease (CKD) patients undergoing hemodialysis.
• Previous studies, including the Normal Hematocrit Cardiac Trial (NHCT), investigated the effects of normalizing hematocrit/hemoglobin levels.
• Higher hematocrit targets were associated with increased thrombovascular events and mortality.

Purpose of the Study:

• To expand and clarify the results of the NHCT.
• To highlight findings from recent studies on CKD anemia normalization.
• To investigate the paradoxical lack of association between higher hemoglobin and mortality within randomized groups.

Main Methods:

• Analysis of data from the Normal Hematocrit Cardiac Trial (NHCT).
• Inclusion of data edited from the original NHCT publication.
• Review of subsequent trials and meta-analyses on CKD anemia normalization.

Main Results:

• The NHCT and meta-analyses showed increased thrombovascular events and mortality with higher hematocrit targets (42% vs. 30%).
• No randomized trials reported a direct association between higher hemoglobin and mortality within groups.
• Mean platelet count did not increase in normal-hematocrit groups in NHCT, CREATE, and CHOIR trials.

Conclusions:

• Efforts to normalize hematocrit/hemoglobin in CKD patients may lead to deleterious outcomes.
• The mechanisms underlying these adverse effects remain unproven.
• Potential confounding factors, such as high-dose erythropoietic stimulating agents and intravenous iron, require further investigation.