Sex, haemoglobin and kidney disease: new perspectives

Anaemia is recognized as a common complication of chronic kidney disease with significant associated morbidity and mortality. Published data document the negative impact of anaemia on cardiovascular disease outcomes, progression of chronic kidney disease (CKD), hospitalizations, rehabilitation and quality of life, among others. Gender differences have been identified in many of these areas as well as, and importantly, in cardiovascular and chronic kidney disease outcomes. Female gender is associated with lower risk of cardiovascular morbidity and mortality as well as slower progression of chronic kidney disease. Interestingly, there are some well-described physiological adaptations to anaemia in women, which include shifting of the haemoglobin oxygen dissociation curve to reduce oxygen affinity secondary to higher levels of 2,3-diphosphoglycerate. However, the complex physiology underlying the impact of anaemia or gender on patients with chronic kidney disease is not well-characterized to date. Furthermore, there has been little examination of the potential interaction between anaemia and gender on cardiac or kidney outcomes. In this paper, we review the documented impact of anaemia and gender on outcomes, and explore the interaction of anaemia and gender in patients with CKD. We also present data that describe the potential importance of considering gender when targeting specific levels of haemoglobin. The value of a new perspective on haemoglobin and gender in kidney disease is important from both a physiological and an economical perspective.