Don’t trouble your heart: Naturally high haemoglobin OK in dialysis patients

Naturally occurring high haemoglobin levels are safe for kidney disease patients on dialysis, according to a study appearing in the Journal of the American Society Nephrology (JASN). The results suggest that there is no need to lower these levels to protect patients’ health.

The vast majority of individuals who develop advanced chronic kidney disease (CKD) also develop progressive anaemia, or red blood cell deficiency, that must be treated with medication. Prior to the approval of erythropoiesis-stimulating agents in 1989, many dialysis patients maintained haemoglobin concentrations < 10 g/dL, with attendant fatigue and the need for repeated blood transfusions.

Treatment is controversial, though, because correcting CKD patients’ anaemia so their target level of haemoglobin, which carries oxygen, is towards the normal range of ~14 g/dL may lead to serious thrombotic complications or even increased risk of death. Researchers have wondered: are dialysis patients whose haemoglobin levels remain high naturally also at risk? Studying these patients provides a natural opportunity to investigate the clinical outcomes associated with higher haemoglobin concentrations in the absence of effects of prescribed drugs.

David Goodkin, MD (Arbor Research Collaborative for Health) and his colleagues studied the health of patients enrolled in the Dialysis Outcomes and Practice Patterns Study (DOPPS), which follows thousands of dialysis patients in 12 countries. Of 29,796 dialysis patients enrolled in the DOPPS with information on haemoglobin levels and medication dose over a 4 month period, 545 (1.8%) maintained haemoglobin concentrations > 12 g/dL without medication to stimulate red blood cell production by the bone marrow.

These patients were more likely to be men, to have been receiving dialysis for more years, and to have underlying cystic kidney disease. Conditions that lower oxygen levels in the blood, such as lung disease, cardiovascular disease, and smoking, were also associated with an increased likelihood of manifesting higher haemoglobin concentrations. The investigators discovered that these patients did not have an elevated risk of dying compared with patients who had lower haemoglobin levels, after adjusting for age, sex, and concomitant diagnoses.

Also, there were no differences in mortality between these patients and the subset of other patients who were taking medications to achieve haemoglobin concentrations > 12 g/dL. While current guidelines caution against prescribing drugs to achieve haemoglobin concentrations > 12 g/dL in kidney disease patients, these findings suggest there is no need to remove blood, or phlebotomize, patients whose haemoglobin levels naturally reach this level without medication. The authors added that “determining the appropriate haemoglobin target range and pharmacological management strategy for dialysis patients is a very complex endeavor and the solution remains a work in progress.”

(Source: American Society of Nephrology: Journal of the American Society Nephrology)