Determinants of the haemoglobin level in patients with sickle cell disease living in sub-Saharan Africa: Major impact of the country of residence and independent effects of leucocyte and platelet counts and haemolysis.

The degree of anaemia in sickle cell disease (SCD) is a well-known contributor to morbidity and mortality. We aimed to explore the factors affecting haemoglobin (Hb) level in African SCD patients, considering haemolysis biomarkers (LDH and bilirubin level, and reticulocyte count), leucocyte and platelet counts and socio-demographic characteristics (gender, age group, country of residence and BMI). The research was part of the CADRE multinational cohort and involved 3699 SCD patients living in Mali, Senegal, Ivory Coast, Democratic Republic of Congo, Gabon and Cameroon: 2936 SS/Sß0, 587 SC and 176 Sß + patients with median Hb level of 8, 11.3 and 11.2 g/dL respectively (p < 0.001). In multivariate analysis conducted in 1394 SS/Sß0 patients, living in Cameroon, female gender, lower BMI, higher haemolysis markers (especially LDH) and higher leucocyte and platelet counts were independently associated with lower Hb level (all p < 0.05). In 497 SC and 156 Sß + patients, female gender (p < 0.001), lower BMI (p < 0.05) and higher platelet counts (p < 0.001) were independently associated with lower Hb level. Anaemia in African SCD patients is not only associated with haemolysis but also with the country of residence, lower BMI and leucocyte or platelet counts which might reflect inflammation related to infectious burden in the region.

Implementing a Care Pathway for small and nutritionally at-risk infants under six months of age: A multi-country stakeholder consultation.

Nutritional vulnerability under the age of 6 months is prevalent in low- and middle-income countries with 20.1% infants underweight, 21.3% wasted and 17.6% stunted in a recent review. A novel Care Pathway for improved management of small and nutritionally at-risk infants under 6 months and their mothers (MAMI) has recently been developed to provide outpatient care at large coverage. We aimed to investigate stakeholders' views on the feasibility of its implementation and to identify barriers and enablers. This was an early stage formative mixed-methods study: an online survey plus in-depth interviews with country-level stakeholders in nutrition and child health from different geographical regions and stakeholder groups. 189 stakeholders from 42 countries responded to the online survey and 14 remote interviews were conducted. Participants expressed an urgent need for improved detection and care for small and nutritionally at-risk infants under 6 months. Whilst they considered the MAMI Care Pathway feasible and relevant, they noted it was largely unknown in their country. The most mentioned implementation barriers were: community-specific needs and health care seeking barriers, health workers' lack of competence in breastfeeding counselling and the absence of a validated anthropometric screening method. Possible enablers for its implementation were: patients' preference for outpatient care, integrating the MAMI care pathway into existing maternal and child health programmes and the possibility of a local pilot project. Adaptation to the local context was considered crucial in further scale-up.

Effects of Senegal haplotype (Xmn1-rs7412844), alpha-thalassemia (3.7kb HBA1/HBA2 deletion), NPRL3-rs11248850 and BCL11A-rs4671393 variants on sickle cell nephropathy.

OBJECTIVE: Sickle cell anemia (SCA) can cause substantial kidney dysfunction resulting in sickle cell nephropathy, which may be affected by the presence of modifier genes. This study evaluates the effects of some modifier genes on sickle cell nephropathy. METHODS: Patients living with SCA were recruited. Alpha-thalassemia (3.7kb HBA1/HBA2 deletion) was genotyped using gap PCR multiplex. Senegal haplotype (Xmn1-rs7412844), BCL11A-rs4671393 and NPRL3-rs11248850 were genotyped using Mass Array. The effects of variants on kidney dysfunction were then evaluated using multivariate analysis. RESULTS: The number of patients living with SCA included in this study was 162 with a median age of 20 years [minimum-maximum: 4-57] and a female frequency of 53.21%. Senegal haplotype, BCL11A-rs4671393 variant were protective factors against albuminuria stage A2 with an odds ratio (OR) of 0.22 (95% CI 0.05-0.90) and 0.27 (95% CI 0.08-0.96) respectively. The combination NPRL3-rs11248850 variant - 3.7kb HBA1/HBA2 deletion was a protective factor against albuminuria stage A2 (OR = 0.087, 95% Cl 0.01-0.78) but it was a risk factor for glomerular hyperfiltration (OR = 17.69, 95% CI 1.85-169.31). CONCLUSIONS: All four variants displayed a protective effect against albuminuria stage A2. The combination alpha-thalassemia - NPRL3-rs11248850 variant is a risk factor for glomerular hyperfiltration.

Influence of Oxidative Stress Biomarkers and Genetic Polymorphisms on the Clinical Severity of Hydroxyurea-Free Senegalese Children with Sickle Cell Anemia.

Oxidative stress would play a role in the pathophysiology of sickle cell anemia (SCA). We tested the impact of common SCA genetic modifiers (alpha-thalassemia, G6PD deficiency, HbF quantitative trait loci; QTL) and pro/antioxidant genes polymorphisms (SOD2 rs4880, XO rs207454, MPO rs233322) on oxidative stress biomarkers (AOPP, MDA, MPO, XO, MnSOD, CAT, GPx) and clinical severity in 301 Senegalese SCA hydroxyurea-free children at steady-state (median age 9.1 years, sex ratio H/F = 1.3). Plasma oxidative stress biomarkers were compared with those of a control group (AA). CAT activity, AOPP, and MDA levels were higher in SCA than in AA individuals while XO, GPX, and MnSOD activities were lower. The presence of alpha-thalassemia decreased MDA level and MPO activity but no effect of the HbF QTL or G6PD deficiency was observed. SCA children who experienced their first hospitalized complication before 3 years old had higher MnSOD and CAT activities than the other children while those with no hospitalized VOC in the previous 2 years presented higher GPX activity. Age of the first hospitalized complication and AOPP levels were affected by the MPO rs2333227 SNP. Our results suggest that alpha-thalassemia modulates oxidative stress in SCA, presumably because of a reduction in the MPO activity.

Inpatient and outpatient treatment for acute malnutrition in infants under 6 months; a qualitative study from Senegal.

BACKGROUND: Treatment of acute malnutrition in infants under 6 months is a relevant topic regarding the global problem of maternal and child malnutrition. While treatment for older age groups has shifted more towards an outpatient, community based approach, young infants are mostly treated in hospital. This study aims to describe barriers and facilitators for outpatient and inpatient treatment of malnourished infants under 6 months in Senegal. METHODS: This qualitative descriptive study uses in-depth interviews with health workers and focus group discussions with mothers of malnourished infants, conducted from June to September 2015 in two case clinics. In data analysis, Collins' 3 key factors for a successful nutrition program were used as a theoretical framework: access, quality of care and community engagement. RESULTS: Within Collins' 3 key factors, 9 facilitators and barriers have emerged from the data. Key factor access: Outpatient care was perceived as more accessible than inpatient concerning distance and cost, given that there is a milk supplement available. Trust could be more easily generated in an outpatient setting. Key factor quality of care: The cup and spoon re-lactation technique was efficiently used in outpatient setting, but needed close supervision. Basic medical care could be offered to outpatients provided that referral of complicated cases was adequate. Health education was more intensive with inpatients, but could be done with outpatients. Key factor community engagement: The community appeared to play a key role in treating malnourished young infants because of its influence on health seeking behaviour, peer support and breastfeeding practices. CONCLUSIONS: Outpatient care does facilitate access, provided that an affordable milk supplement is available. Quality of care can be guaranteed using an appropriate re-lactation technique and a referral system for complications. The community has the potential to be much engaged, though more attention is required for breastfeeding education. In view of the magnitude of the health problem of young infant malnutrition and its strong relationship with breastfeeding practices, an outpatient community-based treatment approach needs to be considered.

Subclinical Cardiac Dysfunction Is Associated With Extracardiac Organ Damages.

Background: Several studies conducted in America or Europe have described major cardiac remodeling and diastolic dysfunction in patients with sickle cell disease (SCD). We aimed at assessing cardiac involvement in SCD in sub-Saharan Africa where SCD is the most prevalent. Methods: In Cameroon, Mali and Senegal, SCD patients and healthy controls of the CADRE study underwent transthoracic echocardiography if aged ≥10 years. The comparison of clinical and echocardiographic features between patients and controls, and the associations between echocardiographic features and the vascular complications of SCD were assessed. Results: 612 SCD patients (483 SS or Sß0, 99 SC, and 19 Sß+) and 149 controls were included. The prevalence of dyspnea and congestive heart failure was low and did not differ significantly between patients and controls. While left ventricular ejection fraction did not differ between controls and patients, left and right cardiac chambers were homogeneously more dilated and hypertrophic in patients compared to controls and systemic vascular resistances were lower (p < 0.001 for all comparisons). Three hundred and forty nine SCD patients had extra-cardiac organ damages (stroke, leg ulcer, priapism, microalbuminuria or osteonecrosis). Increased left ventricular mass index, cardiac dilatation, cardiac output, and decreased systemic vascular resistances were associated with a history of at least one SCD-related organ damage after adjustment for confounders. Conclusions: Cardiac dilatation, cardiac output, left ventricular hypertrophy, and systemic vascular resistance are associated with extracardiac SCD complications in patients from sub-Saharan Africa despite a low prevalence of clinical heart failure. The prognostic value of cardiac subclinical involvement in SCD patients deserves further studies.

Degree of anemia, indirect markers of hemolysis, and vascular complications of sickle cell disease in Africa.

The hyperhemolysis paradigm that describes overlapping "hyperhemolytic-endothelial dysfunction" and "high hemoglobin-hyperviscous" subphenotypes of sickle cell disease (SCD) patients is based on North American studies. We performed a transversal study nested in the CADRE cohort to analyze the association between steady-state hemolysis and vascular complications of SCD among sub-Saharan African patients. In Mali, Cameroon, and Ivory Coast, 2407 SCD patients (1751 SS or sickle ß-zero-thalassemia [Sß0], 495 SC, and 161 sickle ß+-thalassemia [Sß+]), aged 3 years old and over, were included at steady state. Relative hemolytic intensity was estimated from a composite index derived from principal component analysis, which included bilirubin levels or clinical icterus, and lactate dehydrogenase levels. We assessed vascular complications (elevated tricuspid regurgitant jet velocity [TRV], microalbuminuria, leg ulcers, priapism, stroke, and osteonecrosis) by clinical examination, laboratory tests, and echocardiography. After adjustment for age, sex, country, and SCD phenotype, a low hemoglobin level was significantly associated with TRV and microalbuminuria in the whole population and with leg ulcers in SS-Sß0 adults. A high hemolysis index was associated with microalbuminuria in the whole population and with elevated TRV, microalbuminuria, and leg ulcers in SS-Sß0 adults, but these associations were no longer significant after adjustment for hemoglobin level. In conclusion, severe anemia at steady state in SCD patients living in West and Central Africa is associated with elevated TRV, microalbuminuria, and leg ulcers, but these vascular complications are not independently associated with indirect markers of increased hemolysis. Other mechanisms leading to anemia, including malnutrition and infectious diseases, may also play a role in the development of SCD vasculopathy.

Genetic Background of the Sickle Cell Disease Pediatric Population of Dakar, Senegal, and Characterization of a Novel Frameshift ß-Thalassemia Mutation [HBB: c.265_266del; p.Leu89Glufs*2].

Sickle cell disease is a genetic disorder with a large variability in the pattern and severity of clinical manifestations. Different genetic modulators have been identified but very few epidemiologic data are available on these modifier genes in Senegal. This study aimed to determine their prevalence in a Senegalese sickle cell disease pediatric population. The following genetic parameters were genotyped in 295 sickle cell disease children of the Dakar pediatric hospital: sickle cell disease genotype [ßS/ßS (HBB: c.20A>T), ßS/ßC (HBB: c.19G>A), ßS/ß0-thalassemia (ß0-thal)], XmnI polymorphism, the five most common α-thalassemia (α-thal) deletions and the A(-) and Betica glucose-6-phosphate-dehydrogenase (G6PD) deficient variants. Despite very few ßS/ßC and ßS/ß0-thal children (1.0% each), a novel frameshift ß0-thal mutation was characterized: HBB: c.265_266del; p.Leu89Glufs*2. The -α3.7 (rightward) deletion was the only α-thal deletion identified in this cohort (12.0% allelic frequency). Most of ßS/ßS patients (61.9%) were homozygous for the XmnI polymorphism and assumed to carry a Senegal/Senegal ßS haplotype. The remaining haplotypes were predominantly of the Benin type. While the Betica G6PD variant was quite frequent (13.0%), a low frequency of the A(-) variant was detected (1.0-2.0%). The systematic genotyping of the -α3.7 deletion and of the G6PD Betica variant in sickle cell disease patients from Senegal could be useful to identify patients at risk for several complications, such as cerebral vasculopathy, where it has been demonstrated that a normal α-globin genotype and G6PD deficiency are predisposing factors. These patients should be eligible for a transcranial Doppler examination that is not routinely offered in Senegal.

[Epidemiological, clinical and hematological profiles of homozygous sickle cell disease during the intercritical period among children in Ziguinchor, Senegal]. / Profils épidemiologiques, cliniques et hématologiques de la drépanocytose homozygote SS en phase inter critique chez l'enfant à Ziguinchor, Sénégal.

Sickle cell disease poses a public health problem in Senegal. It mainly affects children and adolescents. This study aimed to determine the epidemiological, clinical and hematological profiles of homozygous (SS) sickle cell disease in a cohort of children followed-up at the Peace Hospital in Ziguinchor. We conducted a retrospective study of the medical records from children with sickle cell disease. All patients aged between 2 months and 21 years with sickle cell disease SS during the intercritical period, hospitalized during the study period from 1st January 2015 to 31 August 2017 were included in our study. Compound heterozygous patients (SC, S Beta Thalassemia) were not included. We collected 46 medical records of patients with sickle cell disease SS (20 girls and 26 boys). The average age of children was 8,0 years [11 months-21 years]. Approximately 1/3 of children (39.1%) had an age less than or equal to 5 years. There was an ethnic diversity showing a predominance of the Diola (30.2%) followed by the Mandinga (27.9%) and the Poular (25.6%). The average age of children with first crisis was 35,5 months [7-192 months]. More than 1/3 of children (41.3%) had had first crisis before their second anniversary. In the child, first crisis was dominated by vaso-occlusive crisis (32.6%) followed by hand-foot syndrome (30.4%). Clinical signs during the intercritical period were pallor 95.6%), jaundice (36.9%) and splenomegaly (21.7%). Mean white blood cell count was 12465 leucocytes/mm3 [5340-26900]. Hyperleukocytosis greater than 10 000 leucocytes/mm3was found in 34 patients (73.9%). All patients had anemia with an average hemoglobin of 08,6 g/dl [05,7-11,8]. Hemoglobin S rate ranged between 54.6 and 98.4%. Diagnosis and medical management of sickle cell disease SS are delayed in Ziguinchor. Neonatal screening may lead to improve early management of patients in the region.

Arterial Stiffness Impairment in Sickle Cell Disease Associated With Chronic Vascular Complications: The Multinational African CADRE Study.

BACKGROUND: Although a blood genetic disease, sickle cell disease (SCD) leads to a chronic vasculopathy with multiple organ involvement. We assessed arterial stiffness in SCD patients and looked for associations between arterial stiffness and SCD-related vascular complications. METHODS: The CADRE (Coeur Artères et Drepanocytose, ie, Heart Arteries and Sickle Cell Disease) study prospectively recruited pediatric and adult SCD patients and healthy controls in Cameroon, Ivory Coast, Gabon, Mali, and Senegal. Patients underwent clinical examination, routine laboratory tests (complete blood count, serum creatinine level), urine albumin/creatinine ratio measure, and a measure of carotid-femoral pulse wave velocity (cf-PWV) and augmentation index (AI) at a steady state. The clinical and biological correlates of cf-PWV and AI were investigated by using a multivariable multilevel linear regression analysis with individuals nested in families further nested in countries. RESULTS: Included were 3627 patients with SCD and 943 controls. Mean cf-PWV was lower in SCD patients (7.5±2.0 m/s) than in controls (9.1±2.4 m/s, P<0.0001), and lower in SS-Sß(0) than in SC-Sß(+) phenotypes. AI, corrected for heart rate, increased more rapidly with age in SCD patients and was higher in SCD than in control adults. cf-PWV and AI were independently associated with age, sex, height, heart rate, mean blood pressure, hemoglobin level, country, and hemoglobin phenotype. After adjustment for these correlates, cf-PWV and AI were associated with the glomerular filtration rate and osteonecrosis. AI was also associated with stroke, pulmonary hypertension, and priapism, and cf-PWV was associated with microalbuminuria. CONCLUSIONS: PWV and AI are deeply modified in SCD patients in comparison with healthy controls. These changes are independently associated with a lower blood pressure and a higher heart rate but also with the hemoglobin phenotype. Moreover, PWV and AI are associated with several SCD clinical complications. Their prognostic value will be assessed at follow-up of the patients.

Early renal damage in patients with sickle cell disease in sub-Saharan Africa: a multinational, prospective, cross-sectional study.

BACKGROUND: Chronic kidney disease is one of the leading causes of mortality in patients with sickle cell disease. However, it has been almost exclusively studied in patients with the SS phenotype and in high-income countries, despite more than 80% of patients living in Africa. We looked for the determinants of glomerulopathy in a multinational cohort of patients with sickle cell disease of different phenotypes in sub-Saharan Africa. METHODS: In the CADRE cohort, we prospectively included patients 3 years and older with sickle cell disease of all haemoglobin phenotypes in Cameroon, Côte d'Ivoire, Mali, and Senegal. All individuals were assessed at steady state. The main outcome of interest was albuminuria defined as a urine albumin-to-creatinine ratio of greater than 30 mg/g. We investigated the clinical and biological determinants (including haemolysis markers) of albuminuria in two main phenotype groups (SS and Sß(0); SC and Sß(+)) with further stratification by age and country. FINDINGS: The study is ongoing because of follow-up. 2582 patients with sickle cell disease were included (1776 SS, 136 Sß(0), 511 SC, and 159 Sß(+)). 644 patients with the SS and Sß(0) phenotypes (33·7%, 95% CI 31·6-35·8) and 110 with the SC and Sß(+) phenotypes (16·4%, 13·6-19·2) had albuminuria. In the SS and Sß(0) group, albuminuria was detected in 144 (27%) of 527 children younger than 10 years and its frequency increased with age (29 [48%] of 60 patients aged >40 years). Multivariable analysis showed that albuminuria was associated with age (odds ratio 1·43, 95% CI 1·20-1·71; p<0·0001), female sex (1·35, 1·02-1·82; p=0·045), low haemoglobin (0·79, 0·66-0·93; p=0·006), high lactate dehydrogenase concentrations (1·33, 1·14-1·58; p=0·0009), and, using Côte d'Ivoire as the reference, Mali (2·49, 1·64-3·79; p=0·042) and Cameroon (1·59, 1·01-2·51; p=0·0007) in patients with the SS and Sß(0) phenotypes. The magnitude of the association of albuminuria with haemoglobin and lactate dehydrogenase concentrations increased with age. In the SC and Sß(+) patients, only low haemoglobin (0·69, 0·48-0·97; p=0·029), high blood pressure (1·63, 1·17-2·27; p=0·0017), and Mali (3·75, 1·75-8·04; p<0·0001) were associated with albuminuria. INTERPRETATION: Hyperhaemolysis is associated with albuminuria, with an age-dependent effect, in the SS and Sß(0) phenotypes only, suggesting a different pathological mechanism for glomerular disease in the patients with SC and Sß(+) phenotypes. However, both phenotypes are associated with a high prevalence of albuminuria in childhood. Therefore, screening for albuminuria is advised in African children with sickle cell disease to detect early renal damage. FUNDING: Paris Cité Sorbonne University (GrEX project) and Cardiology and Development.