Investigation of Selected Patient Groups From The Cooperative Study of Sickle Cell Disease

BACKGROUND:

The Cooperative Study of Sickle Cell Disease was initiated in 1977 to determine the natural history of sickle cell disease from birth to death in order to identify those factors contributing to the morbidity and mortality of the disease. Patients in the study had been followed previously in CSSCD.

Follow-up of the newborn cohort provided data demonstrating that life-threatening septicemia can occur as early as four months of age, and that the incidence of septicemia in children with sickle cell disease is higher than previously reported. Serial measurements of pocked or vesiculated red blood cells determined the onset of splenic dysfunction. The loss of splenic function has been characterized by genotype and the observed patterns of loss of splenic function were different developmentally depending on the sickle hemoglobinopathy syndrome.

Growth retardation, which becomes obvious around seven years of age, has no relationship to reported family income. Prophylactic oral penicillin can decrease morbidity and mortality associate with pneumococcal septicemia. The newborn infant cohort was unique in determining issues related to the natural history of the disease because the information was prospective and has been captured in the database. The complex database permitted an opportunity to determine outcomes, risk factors, and the application of the severity index to determine the spectrum of severity.

Follow-up of the over-35 cohort is important because it was not so long ago that it was estimated that 50 percent of patients with sickle cell anemia in the United States died before their twentieth birthday. However, data accumulated over the past eight years by the CSSCD demonstrates that this is incorrect. Survival beyond the age of forty suggests that surviving patients are somehow different from other patients with a high mortality in the earlier years. Therefore, they constitute a cohort of special interest, and the reasons for prolonged survival in this disease remain to be well documented prospectively. Technology is now available to identify genetic differences which may influence survival.