The degrees of hemolysis and anemia in sickle cell disease (SCD) are highly correlated, but are independently associated with measures of cardiopulmonary function and have different predictors, according to a new study published in Clinica Chimica Acta.

“Our analysis suggests that, despite being inter-related, the degrees of hemolysis and of anemia make independent contributions to cardiopulmonary dysfunction and that treatments that specifically target both aspects of SCD may be more [effective] in moving laboratory tests toward the normal range and in ameliorating life-limiting organ damage,” the study’s authors said.

The degrees of hemolysis and anemia were both independently associated with higher values for left atrial diameter and left ventricular end-diastolic diameter and lower values for percent predicted forced expiratory volume in the first second.

Moreover, the authors observed independent associations of the degree of hemolysis, but not anemia, with lower values for oxygen saturation, forced vital capacity, and total lung capacity. On the other hand, they identified independent associations of the degree of anemia, but not hemolysis, with lower values for diastolic blood pressure and mean arterial pressure and higher values for tricuspid regurgitant jet velocity (TRV). They also identified a trend of an association between the degree of hemolysis and increased TRV.

Further analysis uncovered severe sickling genotype and white blood cell as independent predictors of both the degree of hemolysis and the degree of anemia. On the other hand, increasing age and female gender were identified as independent predictors of the degree of anemia, while male gender was identified as an independent predictor of the degree of hemolysis.

The study enrolled 442 patients with SCD (median age, 31 years; 58% females) who predominantly presented with severe sickling genotype.


Njoku F, Zhang X, Shah BN, et al. Associations of hemolysis and anemia with cardiopulmonary dysfunction in an adult sickle cell disease cohort. Clin Chim Acta. Published online January 7, 2023. doi:10.1016/j.cca.2023.117223