Early Predictors of Renal Dysfunction in Egyptian Patients with β-Thalassemia Major and Intermedia

Clinical features and risk factors of renal dysfunctions in thalassemic patients

INTRODUCTION

Chronic anemia, iron overload, and iron chelation therapy are the main contributing factors for renal complications in thalassemia, e.g., nephrolithiasis, glomerular disease, and renal tubular dysfunction. The prevalence and associated factors for developing renal dysfunctions in Thai patients with thalassemia, however, remained limited. This study aimed to determine the prevalence and risk factors of renal dysfunctions in patients with thalassemia.

METHODS

A cross-sectional study was conducted on adult patients with thalassemia disease at Srinagarind Hospital, Khon Kaen University, Thailand. All patients were evaluated for complete blood count, blood chemistry, urinalysis, and urine biochemistry. Renal tubular dysfunction was defined as existing in at least one of the following parameters including; proteinuria, hypercalciuria, hypouricemia with uricosuria, or hypophosphatemia with phosphaturia. Logistic regression analysis was used to identify associated factors for renal dysfunctions.

RESULTS

Of 105 patients, renal tubular dysfunction was found in 60 patients (57.1%). In multivariate analysis of the clinical risk factors for renal tubular dysfunction in thalassemia patients, age per 10 year increase (adjusted odds ratio [AOR] = 1.4, 95% CI: 1.0-2.0, p value 0.01) and Hb E/beta-thalassemia (AOR = 3.6, 95% CI: 1.3-10.3, p value 0.01) were statistically proven to be associated with renal tubular dysfunction. Hyperuricosuria was a significantly associated factor for microhematuria. (AOR = 2.9, 95% CI: 1.1-8.0, p value 0.03).

CONCLUSIONS

Renal dysfunctions are prevalent in thalassemia patients, with older age and Hb E/beta-thalassemia genotype as significant risk factors for renal tubular dysfunction. Hyperuricosuria is a risk factor for microhematuria. Renal dysfunctions should be recognized and monitored in aging patients with Hb E/beta-thalassemia.

Renal Dysfunction in Pediatric Patients in Iraq With β-Thalassemia Major and Intermedia

Background

With optimum transfusion and chelation therapy, the survival of β-thalassemia patients and the incidence of various complications, including renal complications, have improved.

Objectives

To investigate renal involvement in β-thalassemia patients using serum and urinary biochemical markers of glomerular and tubular dysfunction.

Methods

This case-control study included 69 β-thalassemia major (β-TM) patients, 23 β-thalassemia intermedia (β-TI) patients, and 100 healthy controls, all ranging from 1 to 16 years in age. Blood urea nitrogen (BUN), serum ferritin, serum and urinary levels of creatinine (Cr), uric acid (UA), calcium (Ca), phosphorus (Ph), magnesium (Mg), sodium (Na), and potassium (K), and the urinary albumin/creatinine ratio were evaluated.

Results

The BUN level and the urinary Na/Cr, K/Cr, Ca/Cr, Mg/Cr, Ph/Cr, albumin/Cr, and UA/Cr ratios were significantly higher in the β-thalassemia patients than in the controls. In contrast, the serum Na, K, Ca, and Mg levels were significantly lower in the patients (P<0.05). An elevated urinary UA/Cr ratio was found in 61.9% of β-thalassemia patients, and an elevated urinary Ca/Cr, and urinary albumin/Cr ratio was found in 53.2%. An elevated Na/Cr ratio was found in 41.3%. The serum and urinary renal markers showed no significant differences between patients with β-TM and β-TI, except for microscopic hematuria, which was significantly higher in β-TI patients (34.8%) than in β-TM patients (13%), P>0.02. At an older age, high serum ferritin levels and deferoxamine therapy were associated with significant tubular and glomerular dysfunction in β-thalassemia patients.

Conclusions

Pediatric patients with β-thalassemia have significantly abnormal tubular and glomerular functions, necessitating early detection and monitoring to prevent/reverse renal function deterioration.

Advances in Optical Sensors of N-Acetyl-β-d-hexosaminidase (N-Acetyl-β-d-glucosaminidase)

N-Acetyl-β-d-hexosaminidases (EC 3.2.1.52) are exo-acting glycosyl hydrolases that remove N-acetyl-β-d-glucosamine (Glc-NAc) or N-acetyl-β-d-galactosamine (Gal-NAc) from the nonreducing ends of various biomolecules including oligosaccharides, glycoproteins, and glycolipids. The same enzymes are sometimes called N-acetyl-β-d-glucosaminidases, and this review article employs the shorthand descriptor HEX(NAG) to indicate that the terms HEX or NAG are used interchangeably in the literature. The wide distribution of HEX(NAG) throughout the biosphere and its intracellular location in lysosomes combine to make it an important enzyme in food science, agriculture, cell biology, medical diagnostics, and chemotherapy. For more than 50 years, researchers have employed chromogenic derivatives of N-acetyl-β-d-glucosaminide in basic assays for biomedical research and clinical chemistry. Recent conceptual and synthetic innovations in molecular fluorescence sensors, along with concurrent technical improvements in instrumentation, have produced a growing number of new fluorescent imaging and diagnostics methods. A systematic summary of the recent advances in optical sensors for HEX(NAG) is provided under the following headings: assessing kidney health, detection and treatment of infectious disease, fluorescence imaging of cancer, treatment of lysosomal disorders, and reactive probes for chemical biology. The article concludes with some comments on likely future directions.

β-Thalassemia minor & renal tubular dysfunction: is there any association?

Objective

Beta(β)-thalassemia is one of the most common hereditary hematologic disorders. Patients with thalassemia minor (TM) are often asymptomatic and the rate of renal dysfunction is unknown in these patients. Due to the high prevalence of renal dysfunction in Iran, the current study aimed to determine renal tubular dysfunction in patients with beta-TM.

Methods

In this case-control study, 40 patients with TM and 20 healthy subjects were enrolled and urinary and blood biochemical analysis was done on their samples. Renal tubular function indices were determined and compared in both groups. Data was analyzed by SPSS software, version 20.0.

Results

The fraction excretion (FE) of uric acid was 8.31 ± 3.98% in the case and 6.2 ± 34.71% in the control group (p = 0.048). Also, FE of potassium was significantly higher in patients with TM (3.22 ± 3.13 vs. 1.91 ± 0.81; p = 0.036). The mean Plasma NGAL level was 133.78 ± 120.28 ng/mL in patients with thalassemia and 84.55 ± 45.50 ng/mL in the control group (p = 0.083). At least one parameter of tubular dysfunction was found in 45% of patients with thalassemia.

Conclusion

Based on the results of this study, the prevalence of tubular dysfunction in beta-thalassemia minor patients is high. Due to the lack of knowledge of patients about this disorder, periodic evaluation of renal function in TM patients can prevent renal failure by early diagnosis.

Detection of Renal Insufficiency in a Cohort of Patients With Beta-thalassemia Major Using Cystatin-C

With increased life expectancy among patients with beta-thalassemia major (β-TM) renal insufficiency has been frequently noted because of the persistence of anemia, iron overload and some drug side effects. Serum creatinine becomes elevated in late stage of kidney affection. Cystatin-C is more sensitive biomarker for kidney dysfunction. Our aim was to measure Cystatin-C serum level among patients with β-TM as a marker of early nephropathy. Serum Cystatin-C was measured in 94 patients with β-TM using Enzyme-Linked Immunosorbent Assay (ELISA) and correlated to other clinical, laboratory and radiologic data. Glomerular hyperfiltration was observed in 30.8% while Cystatin-C was elevated in 56.3% of β-TM. Patients having high serum Cystatin-C were older in age and having higher serum levels of aspartate aminotransferases and urea. Cystatin-C level was positively correlated with serum creatinine and urea and negatively correlated with glomerular filtration rate. Periodic assessment of Cystatin-C in patients with β-TM is recommended for early diagnosis of renal dysfunction especially during drug dosing prescription aiming to obtain the maximum effectiveness and safety. Controlling anemia by maintaining appropriate hemoglobin level with close monitoring of iron overload are also recommended to preserve renal function among β-TM patients.

Comparing different markers of tubular dysfunction in transfusion-dependent thalassemia patients

BACKGROUND

Renal tubular dysfunction was reported in transfusion-dependent thalassemia (TDT) patients and ranges from mild to severe. The objectives of our study were identification of the best marker of early renal tubular dysfunction in TDT patients among the three most commonly used urinary biomarkers, named neutrophil gelatinase-associated lipocalin (NGAL), retinol-binding protein (RBP) and N-acetyl-D-glucosaminidase (NAG) and correlation of these biomarkers with different patient variables.

METHODOLOGY

Sixty-one TDT patients and another 62 healthy children were enrolled in a cross-sectional study. Morning urine samples were taken for measurement of calcium, phosphorus, creatinine, microalbumin and markers of tubular dysfunction (NGAL, NAG and RBP). Urine NGAL/creatinine (UrNGAL/Cr), urine NAG/creatinine (UrNAG/Cr) and urine RBP/creatinine (UrRBP/Cr) ratios were used for accuracy. Patients were classified into 2 groups: group A, with tubular dysfunction and group b, without tubular dysfunction.

RESULTS

Group A showed statistically significant higher UrNGAL/Cr (p < 0.001), UrRBP/Cr (p < 0.001) and UrNAG/Cr (p <0.001) than group B. In group A, microalbuminuria was detected only in 7 patients (28%) while it was detected in 12 patients (33.3%) in group B. By using ROC curve analysis, the diagnostic cutoff values for UrNGAL/Cr, UrRBP/Cr and UrNAG/Cr were 3713.38, 1614.85 and 56.56 ng/g, respectively. We found a statistically significant superiority of UrNGAL/Cr over UrRBP/Cr (p < 0.001) and UrRBP/Cr over UrNAG/Cr (p < 0.001).

CONCLUSION

Evaluation of UrNGAL/Cr, UrRBP/Cr and UrNAG/Cr could early discriminate tubular dysfunction TDT patients from those with normal tubular function. UrNGAL/Cr is more accurate in early detection of tubular dysfunction when compared with the other two biomarkers.

Assessment of Subclinical Renal Glomerular and Tubular Dysfunction in Children with Beta Thalassemia Major

Background: A good survival rate among patients with beta thalassemia major (beta-TM) has led to the appearance of an unrecognized renal disease. Therefore, we aimed to assess the role of serum cystatin-C as a promising marker for the detection of renal glomerular dysfunction and N-acetyl beta-D-glucosaminidase (NAG) and kidney injury molecule 1 (KIM-1) as potential markers for the detection of renal tubular injury in beta-TM children. Methods: This case-control study was implemented on 100 beta-TM children receiving regular blood transfusions and undergoing iron chelation therapy and 100 healthy children as a control group. Detailed histories of complete physical and clinical examinations were recorded. All subjected children underwent blood and urinary investigations. Results: There was a significant increase in serum cystatin-C (p < 0.001) and a significant decrease in eGFR in patients with beta-TM compared with controls (p = 0.01). There was a significant increase in urinary NAG, KIM-1, UNAG/Cr, and UKIM-1/Cr (p < 0.001) among thalassemic children, with a significant positive correlation between serum cystatin-C, NAG and KIM-1 as regards serum ferritin, creatinine, and urea among thalassemic patients. A negative correlation between serum cystatin-C and urinary markers with eGFR was noted. Conclusion: Serum cystatin-C is a good marker for detection of glomerular dysfunction. NAG and KIM-1 may have a predictive role in the detection of kidney injury in beta-TM children.

IgA nephropathy associated with thalassemia: a case report

Background

Thalassemia is a group of hereditary diseases characterized by a common recessive monogenic hematological disorder, presenting a significant public health concern in the developing countries. Recent studies have identified the renal effects of thalassemia syndrome. Chronic hypoxia, long-term anemia, iron overload, and iron chelators are the major causes of renal tubular dysfunction and glomerular filtration abnormalities, while glomerulonephritis is not considered a major cause of abnormal urinalysis.

Case presentation

We report a case of a 38-year-old female patient with immunoglobulin A (IgA) nephropathy accompanied by anemia who was misdiagnosed initially, but was diagnosed with alpha-thalassemia after gene tests. We administered a combination of oral prednisolone, leflunomide, and angiotensin receptor blockers as well as folic acid and mecobalamin. During the follow-up, her proteinuria was significantly reduced, and her anemia was improved.

Conclusions

The possibility of occurrence of thalassemia should be considered in IgA nephropathy complicated with refractory anemia, especially in high-incidence areas of the disease.

Cardiorenal syndrome in thalassemia patients

Background

Cardiorenal syndrome (CRS), a serious condition with high morbidity and mortality, is characterized by the coexistence of cardiac abnormality and renal dysfunction. There is limited information about CRS in association thalassemia. This study aimed to investigate the prevalence of CRS in thalassemia patients and also associated risk factors.

Methods

Thalassemia patients who attended the out-patient clinic of a tertiary care university hospital from October 2016 to September 2017 were enrolled onto this cross-sectional study. Clinical and laboratory findings from 2 consecutive visits, 3 months apart, were assessed. The criteria for diagnosis of CRS was based on a system proposed by Ronco and McCullough. Cardiac abnormalities are assessed by clinical presentation, establishment of acute or chronic heart failure using definitions from 2016 ESC guidelines or from structural abnormalities shown in an echocardiogram. Renal dysfunction was defined as chronic kidney disease according to the 2012 KDIGO guidelines.

Results

Out of 90 thalassemia patients, 25 (27.8%) had CRS. The multivariable analysis showed a significant association between CRS and extramedullary hematopoiesis (EMH) (odds ratio (OR) 20.55, p = 0.016); thalassemia type [β⁰/β^E vs β⁰/β⁰ thalassemia (OR 0.005, p = 0.002)]; pulmonary hypertension (OR 178.1, p = 0.001); elevated serum NT-proBNP (OR 1.028, p = 0.022), and elevated 24-h urine magnesium (OR 1.913, p = 0.016). There was no association found between CRS and frequency of blood transfusion, serum ferritin, liver iron concentration, cardiac T2*, type of iron chelating agents, or urine neutrophil gelatinase-associated lipocalin level.

Conclusions

CRS is relatively common in thalassemia patients. Its occurrence is associated with laboratory parameters which are easily measured in clinical practice.

Urinary Metabolic Profile of Patients with Transfusion-Dependent β-Thalassemia Major Undergoing Deferasirox Therapy

INTRODUCTION

Renal dysfunction is a frequent complication in patients suffering from β-thalassemia major (β-TM). The aim of this study was to analyze the renal function and urine metabolomic profile of β-TM patients undergoing transfusions and deferasirox (DFX) therapy, in order to better characterize and shed light on the pathogenesis of renal disease in this setting.

METHODS AND SUBJECTS

40 patients affected by β-TM treated with DFX and 35 age- and gender-matched healthy controls were enrolled in the study. Renal function was assessed. Glomerular filtration rate (GFR) was estimated with CKD-EPI and Schwartz formula for adults and children, respectively. Renal tubular function and maximal urine concentration ability were tested. Urine specimens were analyzed by nuclear magnetic resonance spectroscopy to identify the urinary metabolite profiles.

RESULTS

The study of renal function in β-TM patients revealed normal estimated (e)GFR mean values and the albumin-to-creatinine ratio was <30 mg/g. The analysis of tubular function showed normal basal plasma electrolyte levels; 60% of patients presented hypercalciuria and many subjects showed defective urine concentration. Several amino acids, N-methyl compounds, and organic acids were overexcreted in the urine of thalassemic patients compared with controls.

DISCUSSION

The major finding of this work is that β-TM patients and controls exhibit different concentrations of some metabolites in the urine. Early recognition of urinary abnormalities may be useful to detect and prevent kidney damage.

Renal failure in thalassemia: Thinking outside the box

Berger's disease should be considered an imperative cause of renal dysfunction in thalassemia. This case highlights the importance of early diagnosis, clinicopathological correlation and prompt therapy in Berger's disease.

Beta-thalassemia: renal complications and mechanisms: a narrative review

OBJECTIVES

Beta-thalassemias are a group of recessively autosomal inherited disorders of hemoglobin synthesis, which, due to mutations of the beta-globin gene, lead to various degrees of defective beta-chain production, an imbalance in alpha/beta-globin chain synthesis, ineffective erythropoiesis, and anemia. Improved survival in thalassemic patients has led to the emergence of previously unrecognized complications, such as renal disease.

METHODS

A comprehensive literature review through PubMed was undertaken to summarize the published evidence on the epidemiology and pathophysiology of renal disease in thalassemia. Literature sources published in English since 1990 were searched, using the terms beta-thalassemia, renal disease.

RESULTS

Renal disease is considered to be the 4th cause of morbidity among patients with transfusion dependent thalassemia. Chronic anemia, hypoxia and iron overload are the main mechanisms implicated in development of renal injury, whereas several studies also suggested a contributive role of iron chelators.

DISCUSSION AND CONCLUSION

Kidney disease may develop through progressive renal tubular and glomerular damage; thus, its early recognition is important in order to prevent and/or reverse deterioration. This review will provide an insight on the involved mechanisms implicated in kidney disease in thalassemic patients and will discuss the updates on diagnosis and prevention of renal complications in thalassemia.

Renal complications in thalassemia

Thalassemia is a disease with an extensive morbidity profile affecting almost every organ system. Renal involvement, once considered rare, is an underestimated and poorly studied complication that has been on the rise ever since medical advances granted patients longer life spans. Several studies and reports have emerged recently to shed light on the seriousness of this complication, although data is still lacking in terms of pathophysiology, diagnosis, prevention and treatment. In this review, we evaluate and compare renal involvement in the transfusion-dependent and independent variants of β-Thalassemia, highlighting the pathophysiology of kidney damage that involves iron overload, chronic anemia, and iron chelation therapy. An in-depth and focused review of the types of injuries incurred is also presented along with the diagnostic biomarkers accompanying each type of injury. Most research so far has focused on the transfusion-dependent thalassemia population being the group with most renal involvement, however recent reports have shown evidence of comparable, if not worse, involvement of the non-transfusion dependent population, sometimes leading to end-stage renal disease. As such, we try to shed light on distinct renal involvements in NTDT whenever available.

Renal iron deposition by magnetic resonance imaging in pediatric β-thalassemia major patients: Relation to renal biomarkers, total body iron and chelation therapy

BACKGROUND

The reciprocal of multiecho gradient-echo (ME-GRE) T2* magnetic resonance imaging (MRI) R2*, rises linearly with tissue iron concentration in both heart and liver. Little is known about renal iron deposition in β-thalassemia major (β-TM).

AIM

To assess renal iron overload by MRI and its relation to total body iron and renal function among 50 pediatric patients with β-TM.

METHODS

Serum ferritin, serum cystatin C, urinary albumin creatinine ratio (UACR), and urinary β2-microglobulin (β2 M) were measured with calculation of β2 M/albumin ratio. Quantification of liver, heart and kidney iron overload was done by MRI.

RESULTS

Serum cystatin C, UACR and urinary β2 microglobulin as well as urinary β2m/albumin were significantly higher in β-TM patients than the control group. No significant difference was found as regards renal R2* between Patients with mean serum ferritin above 2500 μg/L and those with lower serum cutoff. Renal R2* was higher in patients with poor compliance to chelation therapy and positively correlated to indirect bilirubin, LDH, cystatin C and LIC but inversely correlated to cardiac T2*.

CONCLUSION

kidney iron deposition impairs renal glomerular and tubular functions in pediatric patients with β-TM and is related to hemolysis, total body iron overload and poor compliance to chelation.

Renal Hemosiderosis among Iranian Transfusion Dependent β-Thalassemia Major Patients

Background: In recent years, the success in management of thalassemic patients, has allowed for some previously unrecognized complications including renal abnormalities to emerge. This prospective study aimed to investigate kidney iron overload by means of MRI T2* and also renal function based on laboratory tests for early markers of glomerular and tubular dysfunction among adult Iranian transfusion-dependent thalassemia major patients. Subjects and Methods: Two-hundred and two patients with transfusion-dependent β-thalassemia major were included in this study in Zafar Adult Thalassemia Center, Tehran, Iran. For all patients, kidney MRI T2* as well as evaluation of BUN, creatinine, uric acid, calcium, phosphorus, sodium (Na), potassium (K), total protein, albumin, cystatin C, serum ferritin β2-microglobulin, NAG (N-acetyl-beta-D-Glucosaminidase), and urine protein were performed. Results: One-hundred and fourteen female and 88 male transfusion-dependent β-thalassemia major patients with mean age of 30.1 ± 9.4 participated in the present study. We found that 77.7% of our patients had kidney hemosiderosis based on MRI T2*. Also, 67 patients (33.2%) had elevation of serum cystatin C, and 104 patients (51.5%) had reduced estimated glomerular filtration rate (e-GFR). Increased urinary excretion of NAG and hypercalciuria were found in 50% and 79.2% of participants, respectively. Conclusion: Renal hemosiderosis and asymptomatic renal dysfunction are prevalent among transfusion- dependent β-thalassemia major patients which necessitate regular screening with early markers of glomerular and tubular dysfunction. Further studies in order to investigate the correlation between renal hemosiderosis and early markers of kidney dysfunction among these patients are recommended.

Evaluation of the Relationship Between Hb F Levels and Nucleated Red Blood Cells with Morbidity in Non Transfusion-Dependent Thalassemia Patients

Recognition of risk factors of morbidities in patients with β-thalassemia intermedia (β-TI) is an important issue that must be evaluated. Non transfusion-dependent thalassemia patients referred to the outpatient clinic of Shiraz University of Medical Science, Shiraz, South Iran were enrolled in this study between 2013 and 2014. Two peripheral blood smears were prepared for evaluating developmental stage of normoblasts. One hundred and thirty-one patients with ages ranging from 3 to 42 years (mean: 23.35 ± 7.9) were selected. Sixty-seven patients had at least one morbidity (51.1%). Osteoporosis and gallstones were the most common morbidities (33.6 and 24.4%, respectively). In the univariate model, hemoglobin (Hb), ferritin, Hb F, developmental stage of normoblasts and hydroxyurea (HU) therapy did not differ between patients with and without morbidity (p > 0.05) but mean age of patients and mean number of normoblasts were higher in patients with morbidity (p = 0.026 and p = 0.012, respectively). In the regression model, sex and splenectomy status were different between patients with and without morbidity. It seems that females and splenectomy are risk factors for morbidity in non transfusion-dependent thalassemia patients. [Sex: odds ratio (OR) = 2.21, 95% confidence interval (95% CI): 1.04-4.72, p = 0.39. Splenectomy: OR = 3.10, 95% CI: 1.12-8.59, p = 0.029.] This study shows that Hb F level and developmental stage of normoblasts does not effect the incidence of morbidities in non transfusion-dependent thalassemia patients but sex and splenectomy were effective factors in development of morbidities. Thus, splenectomy should be avoided as much as possible in patients with non transfusion-dependent thalassemia.