Prevalence and correlates of microalbuminuria in children with sickle cell anaemia: experience in a tertiary health facility in enugu, Nigeria

Oxidative stress is associated with markers of renal dysfunction in children aged 6-9 years old in a South African population

INTRODUCTION

although studies have shown a relationship between albuminuria and oxidative stress in adults, limited information on the subject is available in children. The aim of this study was to assess the relationship between oxidative stress and albuminuria in South African children of African ancestry.

METHODS

a cross-sectional study involving 6-9 years old children in randomly selected rural and urban schools of the Eastern Cape Province of South Africa was conducted. Anthropometric measurements were done and urine samples were collected for the determination of titres of albumin, creatinine, 8-hydroxy-2-deoxy-guanosine (8-OHdG) and thiobarbituric acid reactive substances (TBARS). The urinary albumin to creatinine ratio (ACR) was calculated and used to determine albuminuria.

RESULTS

creatinine and 8-OHdG were significantly higher (p<0.05) in urban children than in rural children while albumin, ACR and TBARS were significantly higher (p<0.05) in rural compared to urban children. The prevalence of albuminuria was 14.05% of which microalbuminuria was 8.83% while macroalbuminuria was 5.22%. Albuminuria was higher in rural children than their urban counterparts and was more prevalent in females. TBARS was positively (p<0.05) associated with creatinine and albumin in the cohort as well as in females and urban children while 8-OHdG was positively associated with albumin in the cohort.

CONCLUSION

findings of this study showed that oxidative stress was associated with markers of renal dysfunction with a 14% prevalence of albuminuria observed in South African children of African ancestry.

Co-existing sickle cell anaemia and inflammatory bowel disease: case report and review of the literature

Sickle cell anaemia (SCA) is a chronic haemolytic anaemia associated with vaso-occlusive painful crises which may affect several systems including the gastro-intestinal system, resulting in abdominal pain. The concurrence of inflammatory bowel disease and haemoglobinopathy is rare. No previously reported concurrent cases of both SCA and ulcerative colitis (UC) in sub-Saharan Africa were found in the literature. A 16-year-old girl with concurrent SCA and UC is presented. She was admitted to University College Hospital, Ibadan with a 1-year history of recurrent peri-umbilical pain and bloody stools. These symptoms were mainly attributed to SCA at the referring hospital, and she was managed for chronic tropical diarrhoea without a remarkable clinical response. This case illustrates the concurrent presentation of SCA and ulcerative colitis which led to the missed and delayed diagnosis of ulcerative colitis.

Investigations of Kidney Dysfunction-Related Gene Variants in Sickle Cell Disease Patients in Cameroon (Sub-Saharan Africa)

Background

Renal dysfunctions are associated with increased morbidity and mortality in sickle cell disease (SCD). Early detection and subsequent management of SCD patients at risk for renal failure and dysfunctions are essential, however, predictors that can identify patients at risk of developing renal dysfunction are not fully understood.

Methods

In this study, we have investigated the association of 31 known kidney dysfunctions-related variants detected in African Americans from multi-ethnic genome wide studies (GWAS) meta-analysis, to kidney-dysfunctions in a group of 413 Cameroonian patients with SCD. Systems level bioinformatics analyses were performed, employing protein-protein interaction networks to further interrogate the putative associations.

Results

Up to 61% of these patients had micro-albuminuria, 2.4% proteinuria, 71% glomerular hyperfiltration, and 5.9% had renal failure. Six variants are significantly associated with the two quantifiable phenotypes of kidney dysfunction (eGFR and crude-albuminuria): A1CF-rs10994860 (P = 0.02020), SYPL2-rs12136063 (P = 0.04208), and APOL1 (G1)-rs73885319 (P = 0.04610) are associated with eGFR; and WNT7A-rs6795744 (P = 0.03730), TMEM60-rs6465825 (P = 0.02340), and APOL1 (G2)-rs71785313 (P = 0.03803) observed to be protective against micro-albuminuria. We identified a protein-protein interaction sub-network containing three of these gene variants: APOL1, SYPL2, and WNT7A, connected to the Nuclear factor NF-kappa-B p105 subunit (NFKB1), revealed to be essential and might indirectly influence extreme phenotypes. Interestingly, clinical variables, including body mass index (BMI), systolic blood pressure, vaso-occlusive crisis (VOC), and haemoglobin (Hb), explain better the kidney phenotypic variations in this SCD population.

Conclusion

This study highlights a strong contribution of haematological indices (Hb level), anthropometric variables (BMI, blood pressure), and clinical events (i.e., vaso-occlusive crisis) to kidney dysfunctions in SCD, rather than known genetic factors. Only 6/31 characterised gene-variants are associated with kidney dysfunction phenotypes in SCD samples from Cameroon. The data reveal and emphasise the urgent need to extend GWAS studies in populations of African ancestries living in Africa, and particularly for kidney dysfunctions in SCD.

Assessment of Renal Function Status in Steady-State Sickle Cell Anaemic Children Using Urine Human Neutrophil Gelatinase-Associated Lipocalin and Albumin:Creatinine Ratio

INTRODUCTION

Sickle cell anaemia is characterized by defective haemoglobin synthesis and is associated with both endocrine and metabolic alterations. The effects of this clinical condition on kidney function are multifactorial and often begin early in childhood. This study aims to assess renal function in children with sickle cell anaemia using urine albumin:creatinine ratio (ACR) and urine human neutrophil gelatinase-associated lipocalin (NGAL).

METHODS

This case-control study was conducted on 200 children aged 5-15 years in 2 tertiary hospitals in South West Nigeria: 150 were of haemoglobin S genotype and 50 were of haemoglobin A genotype. Serum urea, creatinine, urine albumin, and NGAL were assayed by known standard methods. eGFR, urine ACR, and urine NGAL/creatinine ratio (urine NCR) were calculated.

RESULTS

The weight, height, BMI, systolic blood pressure, plasma urea, plasma creatinine, and spot urine creatinine of the HbS genotype children were significantly lower compared to that of the HbA genotype children. The eGFR, spot urine albumin, and urine ACR were significantly higher in the HbS group compared to the HbA group. There was no significant difference in the spot urine NGAL and urine NCR between the 2 groups, though both were higher in the HbS group compared to the HbA group.

CONCLUSIONS

Kidney injury probably starts early in childhood in sickle cell individuals as indicated by the higher urine ACR detected in them. We infer that urine NGAL and uNCR are not sensitive markers of kidney disease especially in young sickle cell individuals possibly because of the hyperfiltration present at this age.

Sickle Cell Nephropathy and Associated Factors among Asymptomatic Children with Sickle Cell Anaemia

BACKGROUND

Sickle cell nephropathy (SCN) is a serious complication of sickle cell anaemia (SCA) with asymptomatic onset in childhood and possible progression to chronic kidney disease (CKD). In Southeast Nigeria, few studies have evaluated renal function in paediatric SCA patients for early detection of renal impairment and early intervention to reduce morbidity and mortality. Therefore, this study evaluated the renal function of paediatric SCA patients in a steady state based on glomerular filtration rate and urinalysis findings (proteinuria and haematuria).

METHODS

A cross-sectional study of consecutively recruited sixty haemoglobin SS (HbSS) children in a steady state and sixty age- and sex-matched haemoglobin AA (HbAA) controls aged 2-18 years was done. Renal function of HbSS subjects was evaluated using estimated glomerular filtration rate (eGFR) which was compared with healthy HbAA subjects. The prevalence of significant proteinuria and haematuria, its association with eGFR, and the effect of past sickle cell crisis (in the preceding 24 months) on renal function were also evaluated.

RESULTS

Mean eGFR was significantly higher in HbSS subjects than in the HbAA subjects (p = 0.001) and decreased with age. Significant proteinuria and haematuria were more prevalent in the HbSS group (3.4% and 6.7%, respectively) compared to the HbAA subjects (0% and 0%, respectively) (p = 0.496 and 0.119, respectively). No significant association was observed between eGFR and proteinuria (p = 1.000) or haematuria (p = 1.000). There was a positive correlation between eGFR and frequency of past painful crisis that required hospitalization (r = 0.138, p = 0.295) and between eGFR and frequency of blood transfusion (r = 0.679, p ≤ 0.001).

CONCLUSIONS

Asymptomatic paediatric HbSS (SCA) patients had higher mean eGFR indicating an increased risk of nephropathy. There was no association between eGFR and proteinuria or haematuria. Frequent sickle cell crises especially one requiring transfusion were positively correlated with hyperfiltration.

Prevalence and Risk Factors for Microalbuminuria in Children with Sickle Cell Disease at King Abdulaziz University Hospital: A Retrospective Cross-sectional Study

Objectives: Previous studies have not addressed microalbuminuria in pediatric patients with sickle cell disease (SCD) in Jeddah, Saudi Arabia. This study aimed to determine the prevalence of microalbuminuria and to identify associated risk factors in children with SCD at King Abdulaziz University Hospital.

Results: Overall, 42.5% of the patients enrolled were Saudi Arabian and 51% were male. The mean age was 12.4 years, and the highest percentage (40%) was in the age group of 15-18 years. The prevalence of microalbuminuria was 9.6%, and hematuria was present in 8% of cases. The percentage of patients with hematuria was significantly higher in the microalbuminuria group (22.6%) than in the nonmicroalbuminuria group (6.5%; P = 0.007). The percentage of patients with acute chest syndrome was also higher in the microalbuminuria group (26%) than in the nonmicroalbuminuria group (8%; P = 0.005). The percentage of patients with gallbladder stones was higher in the microalbuminuria group (13%) than in the nonmicroalbuminuria group (2.4%; P = 0.014). However, the mean number of blood transfusions was higher in the nonmicroalbuminuria group than in the microalbuminuria group (P = 0.002). Sickle cell nephropathy manifests as microalbuminuria, begins at an early age, occurs in all types of SCD, and is associated with disease severity.

Microalbuminuria risks and glomerular filtration in children with sickle cell anaemia in Nigeria

INTRODUCTION

Evidence of kidney damage is observed in children with sickle cell anaemia (SCA) and this continues through adulthood with progression to severe functional impairment in some. One of the earliest features of kidney damage associated with SCA is microalbuminuria. Our objective was to determine the risk factors of microalbuminuria in these children and its relationship with estimated glomerular filtration rate.

METHODS

This was a cross-sectional and comparative study involving three hundred and twenty three children with SCA in steady state and equal numbers of apparently healthy age and sex matched haemoglobin AA (HbAA) control, aged 6 months to 18 years. They were consecutively recruited over a 6 month period.

RESULT

Microalbuminuria was present in 26% of the study subjects compared with 1.85% of control P = 0.001). Anaemia and high estimated glomerular filtration rate (eGFR) showed strong positive correlation with microalbuminuria (OR = 3.19, CI 0.953-1.116, p = 0.003 and OR = 1.7, CI 1.042-1.066, p = 0.001 respectively). Similarly, eGFR was higher in subjects with SCA than in controls and as well as in those with microalbuminuria compared with those who do not (p = < 0.01).

CONCLUSIONS

The two most important risk factors for microalbuminuria were anaemia and high eGFR. Age category was associated more with microalbuminuria than just age as a variable. Glomerular filtration rate was higher in children with microalbuminuria than those who do not and it was also higher in children with SCA than in control.

Prevalence and factors associated with renal dysfunction among children with sickle cell disease attending the sickle cell disease clinic at a tertiary hospital in Northwestern Tanzania

BACKGROUND

Little is known on how the interaction between Sickle Cell Disease (SCD) and renal insults caused by other coexisting conditions in Sub Saharan Africa such as urinary schistosomiasis, malnutrition and HIV affect the prevalence of renal dysfunction in children with SCD.

OBJECTIVES

To determine the prevalence and factors associated with renal dysfunction among children with SCD aged 6 months to 12 years attended at a tertiary hospital in Northwestern Tanzania.

METHODS

A cross sectional hospital-based study with a short follow up component of 3 months for 153 children with SCD was done to document demographics, clinical characteristics and features of renal dysfunction including urine dipstick albuminuria (>20mg/l) and eGFR (<60ml/ml/min/1.73m2). Other potential renal insults such as HIV infection and Schistosomiasis were also evaluated.

RESULTS

At enrollment, 48/153(31.37%) children had renal dysfunction declining to 31(20.3%) at 3 months follow up. Acute chest syndrome (OR 3.04, 95% CI [1.08-8.96], p = 0.044), severe anemia (OR 0.44, 95% CI [0.26-0.76],p = 0.003), urinary schistosomiasis (OR 7.43, 95% CI [2.10-26.32] p<0.002) and acute malnutrition (OR 4.92, 95% CI [1.29-18.84], p = 0.020). were associated with renal dysfunction.

CONCLUSION

Where prevalent, urinary schistosomiasis and acute malnutrition increase the risk for renal dysfunction in children with SCD. We recommend albuminuria routine screening in children with SCD especially those presenting with acute chest syndrome, severe anemia and features of acute malnutrition for early detection of renal dysfunction among children with SCD.

Clinical and genetic predictors of renal dysfunctions in sickle cell anaemia in Cameroon

Micro-albuminuria and glomerular hyperfiltration are primary indicators of renal dysfunctions in Sickle Cell Disease (SCD), with more severe manifestations previously associated with variants in APOL1 and HMOX1 among African Americans. We have investigated 413 SCD patients from Cameroon. Anthropometric variables, haematological indices, crude albuminuria, albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR) were measured. Patients were genotyped for 3·7 kb alpha-globin gene (HBA1/HBA2) deletion, and for variants in APOL1 (G1/G2; rs60910145, rs73885319, rs71785313) and HMOX1 (rs3074372, rs743811). The median age was 15 years; the majority presented with micro-albuminuria (60·9%; n = 248), and approximately half with glomerular hyperfiltration (49·5%; n = 200). Age, male sex, haemoglobin level, leucocyte count, mean corpuscular volume, blood pressure, body mass index and creatinine levels significantly affected albuminuria and/or eGFR. Co-inheritance of alpha-thalassaemia was protective against macro-albuminuria (P = 0·03). APOL1 G1/G2 risk variants were significantly associated with the ACR (P = 0·01) and borderline with eGFR (P = 0·07). HMOX1 - rs743811 was borderline associated with micro-albuminuria (P = 0·07) and macro-albuminuria (P = 0·06). The results revealed a high proportion of micro-albuminuria and glomerular hyperfiltration among Cameroonian SCD patients, and support the possible use of targeted genetic biomarkers for risks assessment.

Soluble Fas/FasL ratio as a marker of vasculopathy in children and adolescents with sickle cell disease

OBJECTIVES

Sickle cell disease (SCD) is characterized by chronic inflammation due to ischemic tissue damage, accentuated during acute complications. Fas and its ligand (FasL) are members of tumor necrosis factor receptor superfamily and a major pathway for induction of apoptosis. Fas/FasL interactions may be related to augmentation of inflammatory response. We assessed the levels of sFas and sFasL in 35 children and adolescents with SCD compared with 35 healthy controls in relation to hemolysis, iron overload, sickle vasculopathy including kidney disease.

METHODS

SCD patients, in steady state and asymptomatic for pulmonary hypertension, were studied stressing on hydroxyurea therapy, serum ferritin, urinary albumin creatinine ratio (UACR), high-sensitivity C-reactive protein (hs-CRP) and sFas/sFasL levels.

RESULTS

sFas/sFasL ratio was significantly higher in patients compared with controls. sFas/sFasL ratio was elevated in patients with pulmonary hypertension, nephropathy and those who had history of frequent sickling crisis or serum ferritin ⩾2500. SCD patients treated with hydroxyurea had lower sFas/sFasL ratio than untreated patients. sFas/sFasL ratio was positively correlated to transfusion index, white blood cells, hs-CRP, serum ferritin and UACR. The cutoff value of sFas/sFasL at 8.75pg/mL could differentiate SCD patients with and without nephropathy while the cutoff value at 22pg/mL could differentiate SCD patients with and without pulmonary hypertension risk with high sensitivity and specificity.

CONCLUSION

sFas/sFasL ratio may be considered as a marker for vascular dysfunction in SCD patients and is related to inflammation, iron overload and albuminuria level. Thus, it may be a reliable method to assess renal impairment in SCD.

Bioelectric impedance analysis of body composition of children and adolescents with sickle cell anemia in Enugu, Nigeria

BACKGROUND

Body composition indices are widely used to evaluate growth and nutrition in children, particularly those with sickle cell anemia (SCA), who are known to have impaired growth, impaired skeletal maturation, and delayed puberty. The current study is aimed at determining the body composition of children with SCA.

METHODS

Consecutive selection of SCA children aged 6 to 18 years, who served as subjects and their age and gender matched children with HbAA (controls), selected using multi-stage systematic sampling. It was a cross-sectional descriptive study conducted at the pediatric hematology and oncology clinic. Bioelectric impedance analysis was used to determine the body composition parameters, including weight, body fat percentage (BFP), visceral fat percentage, body mass index (BMI), skeletal muscle percentage, and resting metabolic rate. Data were analyzed using SPSS 16.0 at P < 0.05.

RESULTS

One hundred and thirty-two subjects and controls respectively were studied. Subjects had lower body composition parameters compared with controls, with the older male subjects aged 10 to 18 years, having lower body composition indices (weight, height, BMI, and BFP) compared with controls. Visceral fat percentage was low in both subjects and controls.

CONCLUSIONS

Children with SCA, particularly the older males, have impaired body composition indices. There is a need to conduct further studies to determine the longitudinal aspects of growth as well as quantitative and qualitative assessment of nutritional intake in children with SCA, which will inform higher alimentation requirements for HbSS children as compared with HbAA individuals.

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 Sβ(0); SC and Sβ(+)) 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 Sβ(0), 511 SC, and 159 Sβ(+)). 644 patients with the SS and Sβ(0) phenotypes (33·7%, 95% CI 31·6-35·8) and 110 with the SC and Sβ(+) phenotypes (16·4%, 13·6-19·2) had albuminuria. In the SS and Sβ(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 Sβ(0) phenotypes. The magnitude of the association of albuminuria with haemoglobin and lactate dehydrogenase concentrations increased with age. In the SC and Sβ(+) 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 Sβ(0) phenotypes only, suggesting a different pathological mechanism for glomerular disease in the patients with SC and Sβ(+) 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.