Session: ASH Poster Walk on What's Hot in Sickle Cell Disease Clinical Research in 2023
1Public Health Institute, Tracking California, Richmond, CA; 2As One Foundation, Houston, TX; 3Department of Pediatrics, Division of Hematology, University of California San Francisco Benioff Children's Hospital, Oakland, CA; 4Public Health Institute, Tracking California, Oakland, CA
This longitudinal analysis included all live births with SCT identified by the California newborn screening (NBS) program between 1991 and 2013. For each newborn with SCT, three matched controls with hemoglobin AA were randomly selected from the NBS cohort. Controls were matched to SCT cases on year of birth, sex, race/ethnicity, and city of birth. SCT records with incomplete data for the matched variables or those with fewer than three matching controls were excluded from the analysis. SCT cases and controls were linked to all deaths within the state of California for the years 1991-2013 using statewide death data files. Cox proportional hazard ratios and 95% confidence intervals were calculated to compare mortality between individuals with SCT and controls with hemoglobin AA, including stratified by age (<1, 1-4, 5-14, 15-22).
The study identified 94,240 live births with SCT (Table 1), which represents 96% of all SCT live births identified by the California NBS program in 1991-2013, and 282,720 matched controls. Between 1991 to 2013, there were 693 (0.74%) SCT deaths and 1,910 (0.68%) control deaths. Those with SCT had an increased mortality hazard rate compared to those with hemoglobin AA (11% higher, p=0.015). When stratified by age, mortality hazard rates in the age strata 1-4 years (44% higher, p= .0009) and 5-14 years (48% higher, p=.0047) were higher than those with hemoglobin AA (Table 2). These age strata describe periods of follow up time, and an individual may appear in more than one stratum. Mortality hazard ratios calculated for each age stratum are conditional to individuals surviving to the starting age of that stratum.
This analysis of mortality risk for a cohort of over 94,000 infants identified with SCT is the first of its kind and adds important information to the assessment of health risk for the condition. This is the first study that reports a higher risk of mortality for children and young adults with SCT compared to those with hemoglobin AA. These findings highlight the need for comprehensive research, including confirming the study results in other longitudinal sickle cell trait population-level studies and investigation into underlying causes of death, to inform clinical management and counseling for individuals with SCT.
Disclosures: No relevant conflicts of interest to declare.
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