Splenectomy is a risk factor for developing hyperuricemia and nephrolithiasis in patients with thalassemia intermedia: A retrospective study

Renal Findings in Patients with Thalassemia at Abdominal Ultrasound: Should We Still Talk about "Incidentalomas"? Results of a Long-Term Follow-Up

We retrospectively collected all ultrasound imaging data of our thalassemia patients over a period of 10 years with the aim of assessing the prevalence and the risk factors of renal stones and cysts. Moreover, we assessed the incidence of renal-cell carcinoma (RCC) among thalassemia patients (133 with thalassemia major (TM) and 157 with thalassemia intermedia (TI)) and its association with demographic and clinical findings. Renal stones were detected in 15.2% of patients. In the multivariable Cox regression analysis, the independent predictors were blood consumption, splenectomy, and proteinuria. Renal cysts were detected in 18.4% of patients. In the multivariable analysis, age emerged as the only independent predictor. After the first detection, 35% of the patients showed changes in the number, size, or grading of renal cysts. During the study period, the crude incidence rate of RCC was 75.9 cases per 100,000 person-years. The most frequent histological subtype (80%) included clear-cell RCC. In total, 80% of patients with RCC had TM and all were positive for hepatitis C virus antibodies. Thalassemia patients are significantly affected by asymptomatic renal diseases such as stones, cysts, and cancer, suggesting the need for regular screening by imaging.

Beta-thalassaemia major: Prevalence, risk factors and clinical consequences of hypercalciuria

Regular transfusion and chelation therapy produces increased life expectancy in thalassaemic patients who may develop new complications. Since few data are available regarding hypercalciuria in β‐thalassaemia major (TM), the aim of our study was to evaluate its prevalence, risk factors and clinical consequences. We enrolled 176 adult TM patients followed at the Center of Thalassemia of Ferrara. Hypercalciuria was defined by a calciuria of 4 mg/kg/day or more in a 24‐h urine sample. Anamnestic, biochemical and radiological data were collected. Hypercalciuria prevalence was reported in 69.3% of patients (females 52.5%). Hypercalciuric (HC) patients used deferasirox (DFX) more often than normocalciuric (NC) patients (47.5% vs 29.6%; p < 0.05). In HC subjects plasma parathyroid hormone (PTH) (24.1 ± 10.4 vs 30.1 ± 13.2 pg/ml) and phosphate levels (3.6 ± 0.5 vs 3.8 ± 0.7 mg/dl) were lower, whereas serum calcium (9.6 ± 0.4 vs 9.4 ± 0.4 mg/dl) and urinary 24‐h phosphaturia (0.9 ± 0.4 vs 0.6 ± 0.3 g/day) were higher as compared to NC patients (p < 0.05 for all comparisons). Supplementation with oral calcium and cholecalciferol was similar between the groups. A higher rate of kidney stones was present in HC (14.8%) versus NC patients (3.7%) (p < 0.05). Hypercalciuria is a frequent complication in adequately treated adult TM patients. Hypercalciuria prevalence is increased in DFX users whereas haemoglobin level or calcium supplements play no role. A significant proportion of HC patients developed kidney stones.

Thalassemia and hepatocellular carcinoma: links and risks

The increased survival and lifespan of thalassemia patients, in the setting of better iron overload monitoring and chelation, have also however increased the incidence of diseases and complications, which were less likely to develop. Among these, one of the most worrying in recent years is hepatocellular carcinoma (HCC). Due to blood transfusions, many patients with thalassemia are or have been infected with hepatitis C virus (HCV) or hepatitis B virus (HBV), especially those born before the 1990s or in countries in which universal HBV vaccination and safe blood programs are still not completely implemented. However, HCC has also been described in nontransfused patients and in those who are HCV- and HBV-negative. Therefore, other risk factors are involved in hepatocarcinogenesis in thalassemia. The following review analyzes recent literature on the role of different risk factors in the progression of liver disease in thalassemia as well as the importance of surveillance. Treatment of HCC in thalassemia is still highly debated and requires further studies.

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.

Hyperuricemia, urine uric excretion, and associated complications in thalassemia patients

Thalassemia patients have a high cell turnover rate due to chronic hemolysis and ineffective erythropoiesis; therefore, hyperuricemia is anticipated. This study aimed to identify the prevalence of hyperuricemia, gout and nephrolithiasis, conditions associated with serum uric acid (SUA), and urine uric acid excretion (UUA) in thalassemia patients. This was a cross-sectional study in patients aged 15 years or older at Chiang Mai University Hospital. All patients had blood and 24-h urine collection test. We enrolled 112 thalassemia patients in which 67.0% were female, 64.3% had beta thalassemia/Hb E, 76.8% were transfusion dependent, and 59.8% were post splenectomy. The median age was 29 (16-58) years. Mean SUA was 6.7 ± 2.0 mg/dl and hyperuricemia (SUA > 6.8 mg/dl) was found in 47 cases (45.2%). Intact spleen (ORs 4.3, 95%CI 1.55-12.50, p = 0.01) and lower FEuric (ORs 2.08, 95%CI 1.35-3.33, p < 0.01) were associated with hyperuricemia significantly. Seven (6.3%) had gouty arthritis and nine (8%) had microscopic hematuria, one case being confirmed nephrolithiasis. The mean UUA excretion was 981.3 ± 335.0 mg/day and UUA hyperexcretion (> 700 mg/24 h) was found in 83.3%. UUA hyperexcretion patients had renal hyperfiltration 46%, glomerular dysfunction 84%, and tubular dysfunction 7.7%. From our study, hyperuricemia was found in approximately 40% of thalassemia patients but gouty arthritis occurred only in few patients (6%). This may be explained by urinary uric hyperexcretion which is found in over 80%. The significant risk factors for hyperuricemia were intact spleen and lower fraction excretion of uric acid.

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.

Non-Transfusion-Dependent Thalassaemia: A Panoramic Survey from Pathophysiology to Treatment

Non-transfusion-dependent thalassaemia (NTDT) is a rather broad term that encompasses a group of thalassaemia syndromes, most commonly β-thalassaemia intermedia, haemoglobin E/β-thalassemia, and α-thalassaemia intermedia (haemoglobin H disease). Importantly, these entities do not require regular blood transfusions for survival, and therefore have transfusion independence. Clinical morbidities associated with the NTDTs are the end result of the culmination of three principal pathophysiological aberrancies: ineffective erythropoiesis, chronic anaemia (and associated haemolysis), and iron overload. Such complications involve multiple organs and organ systems; hence, the importance of prompt identification of at-risk individuals and holistic management of diagnosed subjects can never be overstated. Several management options, both medical and surgical, remain at the disposal of involved clinicians, with a significant body of data favouring the virtue of iron chelation therapy, fetal haemoglobin induction, and treatment with blood transfusions, the latter only when absolutely indicated, with reservation of splenectomy to a few select cases. Yet, a better understanding of the molecular phenomena at the origin of the disease process in the NTDT syndromes calls for a pressing need to explore novel therapeutic modalities, in light of the increasing incidence of NTDT in the developed world.

Total Antioxidant Capacity in beta-thalassemia: A systematic review and meta-analysis of case-control studies

Total Antioxidant Capacity (TAC), a biomarker measuring the antioxidant potential of body fluids, including redox synergistic interactions, is influenced by the presence of products of catabolism such as bilirubin (BR) and uric acid (UA). Hyperuricaemia and increased BR levels were observed in thalassemia. In order to evaluate the differences in TAC values between thalassemic patients and healthy subjects, we performed a systematic review and meta-analysis of case-control studies. After the exclusion of data deemed unsuitable for meta-analysis inclusion and a study imputed of bias by Trim-and-fill analysis, mean difference (MD) and confidence intervals 95% (CI 95%) were calculated by the random effect model for beta-thalassemia major (BTM) (1351 subjects: 770 thalassemic and 581 controls, from 15 studies) and Trait (BTT) or Hemoglobin E (BTE) (475 subjects: 165 thalassemic and 310 controls, from 5 studies). Despite the differences in clinical symptoms and severity, similar decreased levels of TAC were found in BTM [MD -0.22 (-0.35 -0.09) p<0.001] and BTT or BTE [MD -0.22 (-0.44 -0.01) p<0.05]. In conclusion, UA and BR interference on TAC suggests that corrected TAC and in particular the UA-independent TAC, considering the prominent influence of UA, might be the better approach to evaluate body antioxidant status.

Endocrinopathies, metabolic disorders, and iron overload in major and intermedia thalassemia: serum ferritin as diagnostic and predictive marker associated with liver and cardiac T2* MRI assessment

INTRODUCTION

Endocrinopathies and metabolic disorders-characterized β thalassemic (βT) patients and the prevention and treatment of these comorbidities are important targets to be achieved. The aim of the study was to analyze the diagnostic and prognostic role of ferritin for endocrinopathies and metabolic disorders in βT patients. The ability of iron chelators to treat iron overload and to prevent or reverse metabolic disorders and endocrinopathies was also evaluated.

PATIENTS AND METHODS

Seventy-two βT patients were treated with different chelation strategies during the study. Receiver operating characteristics analysis was employed to calculate the area under the curve for serum ferritin to find the best cutoff values capable of identifying endocrine dysfunction in thalassemic patients. Kaplan-Meier curves were generated to assess the incidence of endocrinopathy. Adjusted risk estimates for endocrinopathy were calculated using univariate followed by multivariate Cox proportional hazard regression analysis.

RESULTS

High ferritin levels were observed in patients with hypothyroidism [1500 (872.5-2336.5) μg/L], hypogonadism [878 (334-2010) μg/L], and in patients with hypoparathyroidism or osteoporosis [834 (367-1857) μg/L]. A strict correlation between ferritin and T2* magnetic resonance imaging of heart (r = -0.64; P:0.0006) and liver (r = -0.40; P:0.03) values was observed. Patients with ferritin values above 1800 μg/L experienced a significantly faster evolution to hypothyroidism [log-rank (χ(2) ):7.7; P = 0.005], hypogonadism [log-rank (χ(2) ):10.7; P = 0.001], and multiple endocrinopathies [log-rank (χ(2) ):5.72; P = 0.02]. Ferritin predicted high risk of endocrine dysfunction independently of confounding factors (HR:1.23; P < 0.0001). The intensification of chelation therapy led to an amelioration of hypothyroidism.

CONCLUSIONS

Ferritin represents a prognostic marker for βT patients and a predictive factor for progression to endocrine dysfunctions. Intensive chelation therapy allows the reversibility of hypothyroidism.