The clinical epidemiology of sickle cell anemia In Africa

Abstract

Sickle cell anemia (SCA) is the commonest severe monogenic disorders of humans. The disease has been highly characterized in high‐income countries but not in sub‐Saharan Africa where SCA is most prevalent. We conducted a retrospective cohort study of all children 0–13 years admitted from within a defined study area to Kilifi County Hospital in Kenya over a five‐year period. Children were genotyped for SCA retrospectively and incidence rates calculated with reference to population data. Overall, 576 of 18,873 (3.1%) admissions had SCA of whom the majority (399; 69.3%) were previously undiagnosed. The incidence of all‐cause hospital admission was 57.2/100 person years of observation (PYO; 95%CI 52.6–62.1) in children with SCA and 3.7/100 PYO (95%CI 3.7–3.8) in those without SCA (IRR 15.3; 95%CI 14.1–16.6). Rates were higher for the majority of syndromic diagnoses at all ages beyond the neonatal period, being especially high for severe anemia (hemoglobin <50 g/L; IRR 58.8; 95%CI 50.3–68.7), stroke (IRR 486; 95%CI 68.4–3,450), bacteremia (IRR 23.4; 95%CI 17.4–31.4), and for bone (IRR 607; 95%CI 284–1,300), and joint (IRR 80.9; 95%CI 18.1–362) infections. The use of an algorithm based on just five clinical features would have identified approximately half of all SCA cases among hospital‐admitted children with a number needed to test to identify each affected patient of only fourteen. Our study illustrates the clinical epidemiology of SCA in a malaria‐endemic environment without specific interventions. The targeted testing of hospital‐admitted children using the Kilifi Algorithm provides a pragmatic approach to early diagnosis in high‐prevalence countries where newborn screening is unavailable.

Realizing effectiveness across continents with hydroxyurea: Enrollment and baseline characteristics of the multicenter REACH study in Sub‐Saharan Africa

“…On average, however, the baseline hematological parameters demonstrated more severe anemia than age‐matched patients in the US and Jamaica, with a mean baseline hemoglobin concentration of 7.3 g/dL across the entire trial. These baseline hematological parameters were consistent with those previously described for other children with SCA in sub‐Saharan Africa . There were several significant differences in baseline laboratory characteristics across sites (Table ) that are possibly due to differences in the unique genetic, nutritional, and environmental backgrounds at each of the four locations.…”

Antisickling Effects of Quercetin may be Associated with Modulation of Deoxyhaemoglobin, 2, 3-bisphosphoglycerate mutase, Redox Homeostasis and Alteration of Functional Chemistry in Human Sickle Erythrocytes.

“…Its administration has been shown to have anti-inflammatory and protein stability effects which could be advantageous in combating SCD associated oxidative stress, inflammation and decreased HbS stability (Askari et al, 2012). These may as well alleviate and possibly reverse throbbing vaso-occlusive events branded by endothelial dysfunction and instigation of the inflammatory as well as coagulation pathway lately described in SCD (Erukainure et al, 2017;Macharia et al, 2018;Sani et al, 2015).…”

“…As one of the congenital disorder, sickle cell disease (SCD) is a health contest for many in Africa and some part of Asia (Macharia et al, 2018). It is appraised that approximately 20 to 30% of the Nigerian inhabitants harbuors sickle cell trait although about 2 to 3% of the population suffer from SCD .…”

Blood use in sub‐Saharan Africa: a systematic review of current data

“…Although our review includes publications as early as the year 2000, the burden of each of these diseases still remains high in SSA. Globally, malarial anemia is the third most common cause of anemia, while the prevalence of the sickle cell gene in some parts of SSA ranges between 10% and 18%, with up to 3% of hospitalized children suffering from SCA . Similarly, the prevalence of PPH (the most common type of obstetric hemorrhage) in SSA ranges between 10% and 23% of deliveries …”