Comorbidities in aging patients with sickle cell disease

Sickle cell disease (SCD) in general and sickle cell anemia in particular is a highly complex disorder both at the molecular and clinical levels. Although the molecular lesion is a single-point mutation, the sickle gene is pleiotropic in nature causing multiple phenotypic expressions that constitute the various complications of the disease. Moreover, despite the fact that SCD is a chronic malady, its manifestations are both acute and chronic. The former include, among other things, the recurrent vaso-occlusive crises (its hallmark) and acute chest syndrome. The chronic complications include most commonly avascular necrosis and leg ulcers. Currently, survival of patients with SCD has improved dramatically thanks to newborn screening, antibiotic prophylaxis, better vaccine, safer blood transfusion and the use of hydroxyurea. It is the advent of these therapies that improved the survival. This improvement, however, introduced a third dimension of the disease: comorbidities that occur in aging people in the general population. There is concern that the gain in survival may be offset by the comorbidities. Thus it is the purpose of this review to identify the comorbidities in the elderly with SCD and differentiate them from the basis disease to implement proper therapies so that better survival could be maintained.