5613081 GAPS IN DATA ON GLOBAL PREVALENCE AND BIRTH PREVALENCE OF SICKLE CELL DISEASE AND SICKLE CELL TRAIT: CALL FOR ACTION TO SCALE UP AND HARMONIZE DATA COLLECTION

Abstract

Background: Sickle cell disease (SCD) and sickle cell trait (SCT) have varying prevalence, which impacts global health. An especially high prevalence has been reported in sub-Saharan Africa, the Mediterranean, the Middle East, and India (Piel FB et al. 2017). The introduction of newborn screening programs has improved life expectancy of patients with SCD; still the mortality rate in some regions is high in children ≤3 years of age (Makani J et al. 2013). With an increased global population movement, the prevalence and disease burden of SCD are changing in various regions. However, there are currently no definitive data on global prevalence and mortality of SCD. Aims: A systematic literature review (SLR) on prevalence, birth prevalence, mortality, and life expectancy of SCD was performed to map the global epidemiological burden. The SLR also allowed identification of any gaps in current data. Methods: A search of bibliographic databases and proceedings from key conferences was performed to identify peer-reviewed studies reporting on SCD (including HbSS, HbSC, sickle beta thalassemia and regional SCD variants) and SCT epidemiology from January 1, 2010 to March 25, 2022 (congress abstracts 2018 to 2022 only). The SLR protocol followed PRISMA guidelines. Two independent reviewers screened titles and abstracts based on predefined inclusion and exclusion criteria. Study quality was assessed with the GRADE framework, adapted to observational studies. For quantitative analyses, studies with at-risk populations, groups not representative of general population, and population size <1,000 were excluded. A binomial normal (BN) random-effects model was applied to estimate prevalence and birth prevalence. Results: Of 1,770 journal articles and 468 abstracts screened, 115 publications met the inclusion criteria for the SLR. Birth prevalence studies were mostly based on cases identified through newborn screening programs. The qualitative and quantitative data showed gaps in the published literature, with missing data on prevalence and/or birth prevalence from key countries and regions. Moreover, no accurate conclusions could be made for mortality/life expectancy, as the number of publications was sparse and the few identified studies were heterogeneous in terms of reporting of SCD genotypes, diagnosis criteria, and study settings. This lack of data requires more research to determine up-to-date and adequate prevention and screening strategies, targeting causes of SCD mortality. Quantitative analyses on the global and regional prevalence and birth prevalence of SCD and SCT are shown in Table 1. If observing these parameters together in this SLR, to gain a comprehensive view, potential “hot spots” for SCD and SCT from high to low prevalence were Africa, Middle East, India, and South America/the Caribbean. Prevalence data for certain regions were inadequate to provide consistent results using the BN model in this SLR, demonstrating the need to scale up systematic data collection by registries, databases, and longitudinal studies. Conclusion: This SLR provides more insight into the global epidemiology of SCD, confirming earlier studies of areas with a high prevalence. However, this SLR demonstrates that resources are needed for additional studies across regions to provide uniform data collection on prevalence and mortality, ensuring an increased SCD awareness among healthcare professionals and public health policy makers worldwide.