Baseline data were collected, including demographic and past medical history and clinical and laboratory information. Stabilized patients were re-examined every six months. Newborns and young infants were re-examined every two to three months. Organ damage to the lungs, spleen, kidneys, eyes, and liver was measured at specific entry and exit points to provide longitudinal data. Data was also gathered on all acute and chronic complications related to sickle cell disease to provide cross-sectional evaluation.