From the *Marian Anderson Comprehensive Sickle Cell Center, St. Christopher's Hospital for Children, Philadelphia, Pennsylvania; †Department of Pediatrics, Drexel University College of Medicine, Philadelphia, Pennsylvania; ‡Department of Pediatrics, Thomas Jefferson University School of Medicine, Philadelphia, Pennsylvania; and the §Comprehensive Sickle Cell Centers Statistical and Data Management Center, Rho Federal Systems Division, Chapel Hill, NC.
Received for publication July 14, 2004; accepted September 28, 2004.
Supported by National Heart, Lung, and Blood Institute, National Institutes of Health, Comprehensive Sickle Center P60 HL-62148, and grants HL-51495, HL-51496, HL-51497.
Reprints: Carlton Dampier, MD, Marian Anderson Comprehensive Sickle Cell Center, St. Christopher's Hospital for Children, Erie Avenue at Front Street, Philadelphia, PA 19134-1095 (e-mail: [email protected]).