Abstract
The Dallas Newborn Cohort is the largest newborn inception cohort of individuals who have sickle cell disease (SCD), and it has provided modern pediatric SCD survival data (
Blood 2004;103:4023–7
). The Cohort includes subjects who were diagnosed at birth by universal newborn screening and followed at our center up to 18 years of age. All subjects with sickle cell anemia (SS) or sickle-β° thalassemia (Sβ°) were prescribed prophylactic penicillin until 5 years of age. The first report from the Cohort showed an overall survival of 85.6% at 18 years for individuals with SS or Sβ°. The standard error of this estimate was high because only 8 individuals remained at risk at 18 years of age at the time of the analysis, which included follow-up until July 2002. Accrual and follow-up of cohort members has continued. We therefore sought to update the survival estimates through age 18 by including three further years of follow-up. By definition the Dallas Newborn Cohort includes all individuals with SS, Sβ°, sickle-hemoglobin C disease (SC), or sickle-β+-thalassemia (Sβ+) who were born in Texas after November 1, 1983, diagnosed by the newborn screening program of Texas, and seen at least once in our center. New members of the Cohort who came to our center between July 2002 and July 2005 were identified. Follow-up of existing members was updated. All deaths and their causes were determined. Subjects were analyzed in two separate groups because of known clinical similarities: SS/Sβ° and SC/Sβ+. Overall survival was analyzed by the Kaplan-Meier method. Subjects were censored at the time of their last clinical encounter. We identified 115 new subjects, and included 1627 additional patient-years of follow-up. The cohort now includes 826 subjects (SS 503, Sβ° 18, SC 247, Sβ+ 58; male:female 427:399) and it provides 7275 patient-years of follow-up. Mean follow-up was 8.9 years (range 0.9–19.5 years). 62 patients (7.5%) were lost to follow-up. There were 25 deaths in the cohort; none was new and all were previously reported. Of the deaths, 15 were likely related to SCD (5 sepsis, 3 acute chest syndrome, 2 multi-organ failure syndrome, 5 other) and 10 were apparently unrelated to SCD (4 trauma or accidental death, 6 other diseases). There were 22 and 3 deaths in the SS/Sβ° and SC/Sβ+ groups, respectively. All the SC/Sβ+ deaths were apparently unrelated to SCD. Overall survival at 18 years for SS/Sβ° and SC/Sβ+ subjects was 92.4% (standard error [SE] 1.9; 52 at risk) and 98.1% (SE 1.3; 12 at risk), respectively. The overall incidence of death through 18 years of age was 0.46 and 0.12 per 100 patient-years, respectively. In conclusion, this updated survival analysis of the Dallas Newborn Cohort now shows that over 90% of children with SS/Sβ° survive childhood, and nearly 100% of children with SC/Sβ+ become adults.Author notes
Corresponding author
2005, The American Society of Hematology
2005
