Clinical findings associated with homozygous sickle cell disease in the Barbadian population--do we need a national SCD registry?

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

The risk of acute events among patients with sickle cell disease in relation to early or late initiation of care at a specialist center: evidence from a retrospective cohort study

BACKGROUND

The greatest disease burden of sickle cell disease occurs early in life. Understanding factors that reduce disease related events in this period is therefore important. Hence, we assessed the impact of early care at a specialist center on the incidence of acute events during the first five years.

METHODS

This was a retrospective cohort study among Jamaican children with sickle cell disease. Medical records of patients born January, 2004 to December, 2009, who were registered at the Sickle Cell Unit, a specialist care facility, were abstracted for dates of initiation to care, first occurrence and frequency of the outcomes of interest (vaso-occlusive crises, acute splenic sequestration, acute chest syndrome, and infection). Patients were classified according to whether initiation of care was before (early) or after 5 months of age (late). Using standardized t-tests, χ2 tests, and a multiple-failure survival analysis the rates of acute events between groups were compared.

RESULTS

Of the total study group (n= 290), homozygous sickle cell disease accounted for 97% and 95% of the early (n=113) and late groups (n=177) respectively. The mean age of presentation in the early and late group was 0.2 and 2.3 years (p<0.01), with a mean length of follow-up of 5.2 and 3.2 years respectively (p<0.01). Vaso-occlusive crisis (n=880) and acute chest syndrome (n= 571) together accounted for 91.6% of the total number of events (n=1584). The risk of vaso-occlusive crisis and acute chest syndrome (among patients who presented with these acute events) was significantly higher in the "late" group, by 43% (Incidence rate ratio, (IRR) = 1.43, p<0.001); 95% CI (1.18-1.72) and 40% (IRR=1.40. p=0.002), 95% CI (1.12-1.75) respectively compared to "early" group. There was no difference in risk between groups for acute splenic sequestration and infection among persons presenting with these events.

CONCLUSION

The risk of acute events in children with sickle cell disease exposed to early care at a specialist care is significantly less. Therefore, widespread screening with rapid referral to a specialist center stands to reduce substantial morbidity in Jamaica and other regions with high prevalence of sickle cell disease.

Biochemical and Molecular analysis of the beta-globin gene on Saudi sickle cell anemia

Sickle cell anemia (SCA) is one of the most common hematologic diseases affecting humans. Detection of a single base pair mutation at 6th codon of β-globin gene is important for the diagnosis of SCA. The aim was to study the nucleotide sequences and the molecular survey of β-globin gene in Saudi patients. Blood samples from 77 unrelated SC patients were obtained from the KKUH, between 2015 and 2017. In this study, DNA was extracted then PCR was performed. Twelve overlapping fragments covering β-globin gene, have been generated by PCR. A total of 47 alterations have been recognized in β-globin gene. These alterations composed of: deletions, insertion or substitutions as follows:- one mutation identified on the 1st segment; three alterations on 2nd fragment; two alterations on 3rd segment; seven alterations on 4th segment; three substitution on 5th fragment; two changes on 6th fragment; five alterations on 7th fragment; seven substitution changes on 8th fragment; two heterozygous substitution changes on 9th fragment; three changes on 10th fragment and eight substitution changes on 11th fragment, and four changes on 12th fragment. SCA had profound negative effects on many organs, causing many complications. The results should be taken further to set up management strategies to improve outcomes.

Newborn Screening for Sickle Cell Disease in the Caribbean: An Update of the Present Situation and of the Disease Prevalence

The region surrounding the Caribbean Sea is predominantly composed of island nations for its Eastern part and the American continental coast on its Western part. A large proportion of the population, particularly in the Caribbean islands, traces its ancestry to Africa as a consequence of the Atlantic slave trade during the XVI-XVIII centuries. As a result, sickle cell disease has been largely introduced in the region. Some Caribbean countries and/or territories, such as Jamaica and the French territories, initiated newborn screening (NBS) programs for sickle cell disease more than 20 years ago. They have demonstrated the major beneficial impact on mortality and morbidity resulting from early childhood care. However, similar programs have not been implemented in much of the region. This paper presents an update of the existing NBS programs and the prevalence of sickle cell disease in the Caribbean. It demonstrates the impact of the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia (CAREST) on the extension of these programs. The presented data illustrate the importance of advocacy in convincing policy makers of the feasibility and benefit of NBS for sickle cell disease when coupled to early care.

Risk of Exertional Heat Illnesses Associated with Sickle Cell Trait in U.S. Military

Introduction

A number of studies have found an association between sickle cell trait (SCT) and exertional heat illnesses (EHIs) including heat stroke, a potentially fatal condition. The strength of this association varied across studies, limiting the ability to quantify potential benefits of SCT-screening policies for competitive athletics and military service members. We determined the relative rate and attributable risk of developing EHI associated with being SCT positive and the EHI health care utilization.

Methods

We conducted a retrospective cohort study among U.S. enlisted, active duty service members during 1992-2012 from the Department of Defense Military Healthcare System databases. All 15,081 SCT-positive individuals and a sample of 60,320 from those considered SCT negative were followed through 2013 for EHI outcomes ranging from mild heat illness to heat stroke.

Results

The adjusted hazard ratio for EHI in SCT-positive compared with SCT-negative individuals was 1.24 (95% confidence interval 1.06, 1.45). Risk factors for EHI included age over 30 yr at enlistment, female gender, Marine Corps, combat occupations, and enlistment between April and June. An estimated 216 Department of Defense enlistees (95% confidence interval: 147, 370) would need to be screened to identify and potentially prevent one case of EHI. The attributable risk of EHI due to SCT was 33% (95% confidence interval 19, 45%).

Conclusion

Our findings suggest that SCT screening will identify approximately a third of SCT individuals at risk for EHI, but does not provide definitive evidence for universal compared with selective (e.g., occupational based) in military enlistees. A cost-effectiveness analysis is needed for policy makers to assess the overall value of universal SCT screening to prevent morbidity and mortality in both the military and the collegiate athletic populations.

The morbidity pattern of children with sickle cell disorders admitted to the Queen Elizabeth Hospital, Barbados (2009-2013)

A retrospective study was conducted by examining all the medical files of all the children with sickle cell anaemia (Hb SS) admitted from 1 January 2009 to 31 December 2013. A total of 220 admission notes (59 patients aged 5 months-16 years) were analysed. Of these, 53.2% were boys; 85.8% of the patients had Hb SS. The most common reason for admission was vaso-occlusive crisis. Blood transfusions were used in 39.7% of admissions There were no deaths during the study period. We note the number of sickle cell-related admissions and morbidity has increased, along with an increase in the number of blood transfusions. The mortality rate for children with sickle cell in Barbados is low compared to other territories in the Caribbean and worldwide. The need for better comprehensive management protocols and universal screening should decrease the morbidity patterns seen in this study.

CAREST--Multilingual Regional Integration for Health Promotion and Research on Sickle Cell Disease and Thalassemia

Sickle cell disease (SCD) is a significant problem in the Caribbean, where many individuals have African and Asian forebears. However, reliable prevalence data and specific health care programs for SCD are often missing in this region. Closer collaboration between Caribbean territories initiated in 2006 to set up strategies to promote better equity in the health care system for SCD patients led to the formation of CAREST: the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia. We present the effectiveness of collaborations established by CAREST to promote SCD newborn screening programs and early childhood care, to facilitate health worker training and approaches for prevention and treatment of SCD complications, and to carry out inter-Caribbean research studies.