Secondary hyperparathyroidism and anemia in children treated by hemodialysis

Study of Red Cell Fragility in Different Stages of Chronic Kidney Disease in Relation to Parathyroid Hormone

INTRODUCTION

Anaemia is one of the common complications associated with Chronic Kidney Disease (CKD) responsible for the increase in the morbidity and mortality in such patients. Several factors have been attributed to cause renal anaemia, amongst which hyperparathyroidism is one of the less recognised reasons. Most studies have been conducted in this regard in CKD patients undergoing haemodialysis. The level of PTH in early stages of chronic kidney disease has not been much studied. The excess amount of Parathyroid Hormone (PTH) secondary to CKD has been suggested to be a causative factor for anaemia.

AIM

To evaluate the serum PTH level in CKD patients before haemodialysis and to study the association of the haemoglobin status with the parathyroid hormone.

MATERIALS AND METHODS

Forty CKD patients above 18 years of age before haemodialysis and 25 age and sex matched healthy controls were included in the study. Routine biochemical and haematological parameters such as Routine Blood Sugar (RBS), urea, creatinine, Na+, K+, Ca2+, PTH and Hb% were perfomed. Red cell osmotic fragility was measured by serial dilutions of whole blood with varying concentrations of sodium chloride ranging from 0.1% to 0.9%.

RESULTS

The study revealed a significant fall in Hb%, along with a rise in Median Osmotic Fragility (MOF) and PTH in the CKD patients when compared to the control group. Linear regression of PTH with Hb% revealed significant negative association between both the parameters with a R2 value of 0.677. Multilinear regression analysis of MOF and other independent variables such as Hb%, Na+, K+, Ca2+, urea, PTH and creatinine highlighted the variance of MOF by 72%, maximal variance contributed by PTH. Receiver Operating Curve (ROC) analysis revealed an area under the curve of 0.980 with a sensitivity of 100% and specificity of 87% in detecting osmotic fragility at a cut off value of PTH ≥100 pg/ml.

CONCLUSION

The underlying cause of anaemia should be identified early in the CKD patients before haemodialysis. Secondary hyperparathyroidism should be ruled out as a causative factor of anaemia to slow down the progression of the disease process.

Evaluation of clinical and laboratory variables associated with anemia in pediatric patients on hemodialysis

OBJECTIVE

To identify the occurrence of anemia in pediatric patients on hemodialysis and the association between hemoglobin levels and anemia in CKD-related variables.

METHODS

This was a retrospective study. Patients aged up to 18 years with chronic kidney disease undergoing hemodialysis at this service between January of 2009 and December of 2010 were selected. Clinical and laboratory data were obtained from medical records. Statistical analysis was performed with chi-squared test, Student's t-test and general estimating equations (GEE) using SPSS 20.0, assuming a significance level of 5%.

RESULTS

A total of 357 medical records depicting the monthly evolution of 29 patients were analyzed. The most common etiology for chronic kidney disease was malformations of the genitourinary tract (28%). Hemoglobin showed a mean (standard deviation) value of 9.20 (1.8) g/dL, with the occurrence of anemia in 65.3% of cases. Anemia was associated with hospitalization; antibiotic use; transfusion; use of intravenous iron hydroxide; low values of creatinine, hematocrit, and albumin; and high values of ferritin, aluminum, and equilibrated Kt/V (p<0.05). The odds ratio for anemia with the use of intravenous iron hydroxide was 0.36 (95% CI: 0.25 to 0.89), i.e., a 2.78-fold higher chance of developing anemia without the use of this medication.

CONCLUSIONS

Anemia predominated in children and adolescents with chronic kidney disease; intravenous iron hydroxide use was a protective factor.

Prevalence and predictors of the sub-target Hb level in children on dialysis

BACKGROUND

Anaemia is a common and potentially treatable co-morbidity of end-stage renal disease. We aimed to determine the prevalence of the sub-target haemoglobin (Hb) level among European children on dialysis and to identify factors associated with a low Hb level.

METHODS

From the European Society for Paediatric Nephrology (ESPN)/European Renal Association-European Dialysis Transplant Association (ERA-EDTA) registry, data were available on 2351 children between 1 month and 18 years of age, totalling 5546 measurements from 19 countries.

RESULTS

The mean Hb level was 10.8 g/dL (5th-95th percentiles, 7.4-13.9). Among those above 2 years of age, the mean Hb level was 10.9 g/dL (11.4% below 8.5 g/dL), while it was 10.3 g/dL among those below 2 years (11.2% below 8.0 g/dL). A total of 91.2% of the patients were on an erythropoiesis-stimulating agent (ESA). Hb levels increased with age and were higher in peritoneal dialysis compared with haemodialysis patients. Patients with congenital anomalies of the kidney and urinary tract showed the highest Hb levels, and those with cystic kidney diseases or metabolic disorders the lowest ones. Ferritin levels between 25 and 50 ng/mL were associated with the highest Hb levels. We found a weak inverse association between parathyroid hormone (PTH) and Hb. Whereas standardized blood pressure (BP) was not elevated in patients with above-target Hb, elevated systolic BP z-score was noted in those with sub-target Hb levels.

CONCLUSIONS

Sub-target Hb levels remain common in children on dialysis, in spite of virtually all children being treated with ESA; although we cannot exclude under-dosing. Optimal ferritin levels seemed to be slightly lower in children (25-50 ng/mL) than those in adults. Other risk factors for sub-target Hb are dialysis modality and a high PTH level.

Cardiovascular disease in children with chronic kidney disease

More than a decade ago, cardiovascular disease (CVD) was recognized as a major cause of death in children with advanced CKD. This observation has sparked the publication of multiple studies assessing cardiovascular risk, mechanisms of disease, and early markers of CVD in this population. Similar to adults, children with CKD have an extremely high prevalence of traditional and uremia-related CVD risk factors. Early markers of cardiomyopathy, such as left ventricular hypertrophy and dysfunction, and early markers of atherosclerosis, such as increased carotid artery intima-media thickness, carotid arterial wall stiffness, and coronary artery calcification, are frequently present in these children, especially those on maintenance dialysis. As a population without preexisting symptomatic cardiac disease, children with CKD potentially receive significant benefit from aggressive attempts to prevent and treat CVD. Early CKD, before needing dialysis, is the optimal time to both identify modifiable risk factors and intervene in an effort to avert future CVD. Slowing the progression of CKD, avoiding long-term dialysis and, if possible, conducting preemptive transplantation may represent the best strategies to decrease the risk of premature cardiac disease and death in children with CKD.

Anemia in children with chronic kidney disease

Anemia is a common comorbidity in children with chronic kidney disease (CKD). This condition is associated with multiple adverse clinical consequences and its management is a core component of nephrology care. Increased morbidity and mortality, increased risk of cardiovascular disease and decreased quality of life have been associated with anemia of CKD in children. Although numerous complex factors interact in the development of this anemia, erythropoietin deficiency and iron dysregulation (including iron deficiency and iron-restricted erythropoiesis) are the primary causes. In addition to iron supplementation, erythropoietin-stimulating agents (ESAs) can effectively treat this anemia, but there are important differences in ESA dose requirements between children and adults. Also, hyporesponsiveness to ESA therapy is a common problem in children with CKD. Although escalating ESA doses to target increased hemoglobin values in adults has been associated with adverse outcomes, no studies have demonstrated this association in children. The question of appropriate target hemoglobin levels in children, and the approach by which to achieve these levels, remains under debate. Randomized, controlled studies are needed to evaluate whether normalization of hemoglobin concentrations is beneficial to children, and whether this practice is associated with increased risks.

Effective treatment of anemia in pediatric kidney transplant recipients with methoxy polyethylene glycol-epoetin beta

MPG-EPO is a continuous erythropoietin receptor activator with a longer half-life than darbepoetin, hence requires less frequent injections. It has been successfully used in adults, but currently, there are no published data available for its use in children. This pilot study was performed to verify the effect of MPG-EPO on Hb levels in children. Twelve patients (age 6.4-17.2 yr) were treated with MPG-EPO as an individual "Heilversuch" according to German law after RTx. Five patients were switched from DA, and seven were naïve to erythropoietin. Over a period of six months, Hb levels were measured monthly. A median MPG-EPO dose of 2.5 μg/kg was administered intravenously in a single dose every four wk. The median Hb value increased in naïve patients from 9.9 to 11.2 g/dL (median, p = 0.004) and from 10.3 to 11.6 g/dL (median, p = 0.39) in patients switched from DA to MPG-EPO. No adverse events secondary to MPG-EPO therapy were detected. Our results indicate that a once-monthly injection of MPG-EPO is an effective treatment of anemia in children after renal transplantation. Larger randomized trials will have to confirm our findings.