Serum erythropoietin and reticulocyte maturity index after renal transplantation: a prospective longitudinal study

A Systematic Review and Meta-Analysis of Posttransplant Anemia With Overall Mortality and Cardiovascular Outcomes Among Kidney Transplant Recipients

Introduction: Posttransplant anemia is a common finding after kidney transplantation. A previous meta-analysis reported an association between anemia and graft loss. However, data on cardiovascular outcomes have not yet been reported. Objective: We conducted an updated meta-analysis to examine the association between posttransplant anemia and outcomes after transplantation including cardiovascular mortality in adult kidney transplant recipients. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to November 2021. Data from each study were combined using the random-effects model. Generic inverse variance method of DerSimonian and Laird was employed to calculate the risk ratios and 95% CIs. Results: Seventeen studies from August 2006 to April 2019 were included (16 463 kidney transplantation recipients). Posttransplant anemia was associated with overall mortality (pooled risk ratio = 1.72 [1.39, 2.13], I² = 56%), graft loss (pooled risk ratio = 2.28 [1.77, 2.93], I² = 94%), cardiovascular death (pooled risk ratio = 2.06 [1.35, 3.16], I² = 0%), and cardiovascular events (pooled risk ratio = 1.33 [1.10, 1.61], I² = 0%). Early anemia (≤6 months), compared with late anemia (>6 months), has higher risk of overall mortality and graft loss with a pooled risk ratio of 2.63 (95% CI 1.79-3.86; I² = 0%) and 2.96 (95% CI 2.29-3.82; I² = 0%), respectively. Discussion: In addition to increased risk of graft loss, our updated meta-analysis demonstrated that posttransplant anemia was significantly associated with poor outcomes after kidney transplantation including overall mortality, graft loss, cardiovascular death, and cardiovascular events. Future studies are required to assess the effects of treatment strategies for posttransplant anemia on posttransplant outcomes including cardiovascular mortality.

Renal association clinical practice guideline on Anaemia of Chronic Kidney Disease

Anaemia is a commonly diagnosed complication among patients suffering with chronic kidney disease. If left untreated, it may affect patient quality of life. There are several causes for anaemia in this patient population. As the kidney function deteriorates, together with medications and dietary restrictions, patients may develop iron deficiency, resulting in reduction of iron supply to the bone marrow (which is the body organ responsible for the production of different blood elements). Chronic kidney disease patients may not be able to utilise their own body's iron stores effectively and hence, many patients, particularly those receiving haemodialysis, may require additional iron treatment, usually provided by infusion.With further weakening of kidney function, patients with chronic kidney disease may need additional treatment with a substance called erythropoietin which drives the bone marrow to produce its own blood. This substance, which is naturally produced by the kidneys, becomes relatively deficient in patients with chronic kidney disease. Any patients will eventually require treatment with erythropoietin or similar products that are given by injection.Over the last few years, several iron and erythropoietin products have been licensed for treating anaemia in chronic kidney disease patients. In addition, several publications discussed the benefits of each treatment and possible risks associated with long term treatment. The current guidelines provide advice to health care professionals on how to screen chronic kidney disease patients for anaemia, which patients to investigate for other causes of anaemia, when and how to treat patients with different medications, how to ensure safe prescribing of treatment and how to diagnose and manage complications associated with anaemia and the drugs used for its treatment.

Chronic renal failure complications and management in kidney transplanted and nontransplanted patients

BACKGROUND

Our purpose was to compare the management of chronic kidney disease (CKD) according to Kidney Disease Quality Initiative (K/DOQI) recommendations in kidney transplanted patients (T) and nontransplanted ones (NT).

METHODS

Data concerning CKD complications were collected retrospectively. Patients seen in consultations in our department from May 2009 to June 2010 were selected if they had at least 6 months of follow-up, CKD stage 4 or 5, and no exclusion criteria namely hospitalization, active cancer, or infection in the 3 months before data collection.

RESULTS

Fifty-eight T were compared with 85 NT matched by CKD stage (4-5). Anemia within K/DOQI target was better controlled among NT (51.2% versus 41.3%); however, ferritin levels within K/DOQI target were higher (80% T versus 51.7% NT). Average arterial blood pressure was similar in both groups but 51.7% of T were in K/DOQI target versus 41% of NT. Dyslipidemia within cholesterol K/DOQI target was better controlled in 60% (NT) versus 35% NT with 63.5% versus 38% NT within low-density lipoprotein K/DOQI targets. Phosphorus level was better controlled among T; parathyroid was better controlled in among 65% NT versus 50% T within the target level.

CONCLUSION

Most complications of CKD were better managed among NT.

Risk factors of post renal transplant anaemia among Sudanese patients, a study in three renal transplant centres

Background

There is a relative lack of recent information about late post kidney transplantation anaemia (PTA), especially in the developing countries; data are scarce about the prevalence and risk factors of PTA. Sudan was a leading country in Africa and Arab world in kidney transplantation. The first kidney transplantation in Sudan was in 1973.

Methods

This is a cross-sectional hospital analytic study enrolling all kidney transplanted recipients following in the transplant referral clinics at Ahmed Gassim, Selma and Ibn Sina Hospitals, Khartoum/Sudan, in the period from 1/8/2010 to 1/9/2010, clinical and laboratory data were obtained from 114 patients, anaemia was defined as Hb levels of < 13 g/dl for male patients and < 12 g/dl for female patients, exclusion criteria were pregnancy, below 18 years old patients, multiple organ transplantation, and patients with less than one year from the transplantation.

Results

The study showed that 39.5% of the patients were anaemic. Univariate analysis showed that late PTA is significantly associated with not using Erythropoietin (EPO) in the pre-transplant period (p = < 0.001), history of rejection (p = 0.003), longer time from transplantation (p = 0.015), and eGFR (p < 0.0001). Multivariate analysis showed that eGFR (p = < 0.001) and not use of EPO in the pre transplant period (p < 0.001) are strong predictors of PTA. The use of Angiotensin converting enzyme inhibitors/Angiotensin receptors blockers (ACEI/ARB), immunosuppressive treatments, presence or absence of co-morbidities, donor type and donor age are not significantly associated with late PTA.

Conclusion

The study concluded that late PTA is common and under recognized. Risk factors for late PTA include renal dysfunction, history of rejection, longer duration of transplantation and not using EPO in the pre-transplant period. Renal dysfunction and not using EPO in the pre-transplant period are major predictors of late PTA.

Reticulocytes and their immature fraction do not detect acute rejection after kidney transplantation

BACKGROUND

Early detection of an acute rejection episode is an important problem in monitoring transplant patients. Erythropoietin (EPO) production is diminished in patients suffering from chronic renal insufficiency or acute rejection. Therefore, a decrease of reticulocyte counts and of young reticulocytes might indicate the emergence of an acute rejection episode. This pilot study examined the value of reticulocyte parameters as indicators of acute rejection episodes.

PATIENTS AND METHODS

Reticulocyte parameters were examined in 25 renal transplant patients. Initial immunosuppressants therapy was based on a combination of methylprednisolone, mycophenolatmofetil, cyclosporine and antithymocyte globulin or basiliximab, CellCept, cyclosporine, and ATG or Simulect. During the first 3 weeks after the procedure, blood samples were collected three times per week. Complete blood counts were performed on XE-2100 analyzers (Sysmex). Acute rejection was biopsy-proven.

RESULTS

Acute rejection episodes were not accompanied by significantly altered reticulocyte parameters. During the first weeks, the reticulocyte count or the immature fraction, respectively, did not differ between patients with delayed versus immediate onset of renal function: reticulocyte count 1.70 +/- 1.06% vs 1.58 +/- 1.10% and ratio of immature (high fluorescent) reticulocytes 22.8 +/- 7.9% vs 17.6 +/- 9.4%).

CONCLUSION

Reticulocyte counts and determination of the immature reticulocyte fraction were not significantly altered by an acute rejection episode. Various influences modulate the release of EPO and reaction of erythropoiesis upon an EPO stimulus.

Anemia in kidney transplanted patients

BACKGROUND

Although a known cardiovascular risk factor, anemia in the renal transplant recipients has only recently been receiving an increasing attention.

METHODS

In a cross-sectional study, data was obtained from 959 patients followed at a single outpatient transplant clinic. Based on the guideline of the American Society of Transplantation, anemia was defined as hemoglobin (Hb) < or =130 g/L in males and < or =120 g/L in females.

RESULTS

About one-third (34%) of the patients were anemic. The prevalence of anemia was comparable in males and females. Serum Hb concentration was significantly correlated with the estimated glomerular filtration rate (eGFR) (abbreviated modification of diet in renal disease formula) (r = 0.266, p < 0.001), serum transferrin (r = 0.268, p < 0.001) and serum albumin (r = 0.196, p < 0.001). None of the immunosuppressive medications or the use of angiotensin converting enzyme inhibitors was associated with a higher likelihood of anemia. In multivariate analysis the eGFR, serum albumin and serum transferrin, potential markers of nutritional status and/or chronic inflammation, and also iron deficiency were independently and significantly associated with anemia. Erythropoietin was administered only to 63 (19%) anemic patients.

CONCLUSIONS

Post-transplant anemia is a prevalent and under-treated condition. Based on our results we suggest that, besides other factors, protein/energy malnutrition and/or chronic inflammation may be independently associated with anemia. Further studies are needed to determine whether the presence of anemia and its treatment will have an impact on long-term outcomes of this population.

Anemia in the kidney-transplant patient

Anemia, a potentially correctable cardiovascular risk factor, continues to be a major problem in kidney-transplant patients. Erythropoietin levels increase rapidly after successful kidney transplantation, and by 3 months, most patients achieve hemoglobin levels greater than 12 g/dL. Anemia may be caused by problems commonly seen in the general population such as iron deficiency or gastrointestinal blood loss, by immunosuppressive medications, or by more rare abnormalities such as hemolytic uremic syndrome or parvovirus B19-induced aplastic anemia. Iron deficiency is common at the time of transplantation and beyond and frequently contributes to anemia. Markers of iron deficiency (ferritin or transferrin saturation) are frequently inconclusive because of the presence of inflammation and infection. Immunosuppressive medications, such as azathioprine and mycophenolate mofetil (MMF), are a common cause of mild bone-marrow suppression and, thus, anemia. Sirolimus can cause more severe bone-marrow suppression, although this effect can lessen over time. The transplant patient with chronic kidney disease (CKD) frequently develops anemia, yet agents such as epoetin-alpha and darbepoetin are greatly underutilized. Evaluation of anemia should be undertaken when hemoglobin fails to normalize by 3 months after transplantation. Later after transplantation, especially in the setting of chronic allograft dysfunction, evaluation should take place when the hemoglobin falls to less than 11 g/dL in premenopausal females or to less than 12 g/dL in males and postmenopausal females.

Evaluation of erythropoiesis and changes in serum erythropoietin concentration in cats after renal transplantation

OBJECTIVE

To investigate the clinicopathologic patterns of the erythropoietic response after renal transplantation in cats with chronic renal failure (CRF).

ANIMALS

14 cats with CRF undergoing renal transplantation.

PROCEDURE

Before and at intervals during a 6-month period after transplantation, serum creatinine and erythropoietin concentrations, Hct, erythrocyte indices, aggregate reticulocyte percentage, and iron variables were measured. Additionally, the number of transfusions administered to and any complications that developed in each cat were recorded.

RESULTS

In all cats, preoperative azotemia resolved within 6 days after renal transplantation. Two cats had a temporary increase in serum creatinine concentration secondary to an acute graft rejection episode. Anemia (defined as Hct < 28%) resolved in 10 cats 3 to 49 days after surgery. Resolution of anemia was delayed in 2 cats that had acute rejection episodes. Serum erythropoietin concentration and reticulocyte percentage were low preoperatively; values after surgery were highly variable. Compared with preoperative values, serum erythropoietin concentration increased 1 to 4 days after surgery in 11 cats; between days 5 and 58, another increase was detected in 9 cats. Serum iron concentrations were generally low before and 14 days after transplantation.

CONCLUSION AND CLINICAL RELEVANCE

The erythropoietic response was highly variable in cats after renal transplantation, but anemia typically resolved within 1 month after surgery. A delay in resolution of anemia in cats may indicate poor graft function and inadequate iron stores, suggesting the need for further evaluation for concurrent illness.

Molecular profiling of anemia in acute renal allograft rejection using DNA microarrays

Compromised renal function after renal allograft transplantation often results in anemia in the recipient. Molecular mechanisms leading to anemia during acute rejection are not fully understood; inadequate erythropoietin production and iron deficiency have been reported to be the main contributors. To increase our understanding of the molecular events underlying anemia in acute rejection, we analyzed the gene expression profiles of peripheral blood lymphocytes (PBL) from four pediatric renal allograft recipients with acute rejection and concurrent anemia, using DNA microarrays containing 9000 human cDNA clones (representing 7469 unique genes). In these anemic rejecting patients, an 'erythropoiesis cluster' of 11 down-regulated genes was identified, involved in hemoglobin transcription and synthesis, iron and folate binding and transport. Additionally, some alloimmune response genes were simultaneously down-regulated. An independent data set of 36 PBL samples, some with acute rejection and some with concurrence of acute rejection and anemia, were analyzed to support a possible association between acute rejection and anemia. In conclusion, analysis using DNA microarrays has identified a cluster of genes related to hemoglobin synthesis and/or erythropoeisis that was altered in kidneys with renal allograft rejection compared with normal kidneys. The possible relationship between alterations in the expression of this cluster, reduced renal function, the alloimmune process itself, and other influences on the renal transplant awaits further analysis.

Unexpectedly high prevalence of posttransplant anemia in pediatric and young adult renal transplant recipients

BACKGROUND

Although posttransplant anemia (PTA) is recognized as a common problem in adult renal transplant recipients, few pediatric studies have been published.

METHODS

In this retrospective cohort study of 162 pediatric renal transplant recipients treated at Stanford University, the authors sought to determine the prevalence, severity, and the predictive factors of PTA. Anemia was defined as a hematocrit (HCT) level greater than 2 SD below published means for age or as erythropoietin dependency to maintain a normal HCT.

RESULTS

Sixty-seven percent of pediatric renal transplant recipients were anemic at the time of transplantation. The prevalence of anemia increased to 84.3% in the first month posttransplant. From 6 months to 60 months posttransplant, the prevalence of anemia remained high at 64.2% to 82.2%. Only 4 patients (2.5%) were never anemic. Iron depletion was detected in 19 of 26 and 23 of 23 anemic patients 12 and 60 months posttransplant, respectively. Serum erythropoietin levels were low relative to hematocrit levels in 38 of 56 anemic patients. Logistic regression at 3 months posttransplant showed that discharge hematocrit level (P < 0.0001), calcium (P = 0.0004), and cyclosporine dose (P = 0.0002) correlated with anemia. Creatinine clearance (P = 0.002) and white blood cell count (P = 0.004) correlated with anemia at 12 months posttransplant, but only creatinine clearance (P = 0.011) correlated with anemia 60 months posttransplant.

CONCLUSION

Nearly all pediatric renal transplant recipients experience PTA. However, few children less than 2 years of age were anemic during the first year posttransplant. Antirejection therapy, bone disease, iron depletion, and creatinine clearance appear to play pivotal roles in the development of PTA in children.

Late post-transplant anemia in adult renal transplant recipients. An under-recognized problem?

Post-transplant anemia (PTA), a frequent complication during the first 3-6 months after transplant, is thought to be uncommon during the late post-transplant period. A study population of adults (> 18 years) transplanted during 1995 at Stanford University (n = 88) and University of North Carolina (n = 40) was selected. Data-collection points were 0, 1, 2, 3, 4 and 5 years post transplant. Anemia was defined as a hematocrit < 33 volume percentage. Thirty percent of patients were anemic at some time during the post-transplant period. The prevalence of PTA increased over time; by 5 years post transplant, 26% of the patients were anemic. Anemia occurred in 62.5% of patients converted from azathioprine to mycophenolate mofetil. A multivariate logistic regression model demonstrated a correlation between anemia and serum total CO2 (p = 0.002), BUN (p = 0.04), and creatinine (p = 0.045) at 1 year post transplant. At 5 years post transplant, only serum total CO2 (p = 0.0004) correlated with anemia. Thus, diminished renal excretory function and metabolic acidosis appear to be the most important correlates of late PTA. These findings should be interpreted in view of the fact that the newer immunosuppressive agents may have an even more profound effect on anemia and its recovery after transplantation.

Reticulocyte analysis by flow cytometry and other techniques

Enumeration of peripheral blood reticulocytes is an essential part of the diagnosis and management of anemic patients, since the number of reticulocytes in the peripheral blood reflects the erythrocytic activity of the bone marrow. Reticulocyte enumeration using flow cytometric methodology is rapidly replacing the inaccurate, imprecise manual counting technique used in the past. This article explores the pathophysiology of the reticulocyte, the various means of counting reticulocytes, and the diverse clinical applications of reticulocyte data.

Diagnostic advances in defining erythropoietic abnormalities and red blood cell diseases

The majority of clinical applications of flow cytometry begin with various approaches to remove red blood cells (RBCs) from the clinical sample. However, multiparameter cytometry has and will continue to contribute much to the understanding of the pathophysiology and diagnostic accuracy in the clinical evaluation of human diseases affecting erythroid cells. This review summarizes the diagnostic advances relating to erythroid cells in the areas of immunohematology, laboratory hematology, and infectious disease with particular emphasis on medical evaluation of the anemic patient and fetomaternal hemorrhage. Semin Hematol 38:148-159.

Erythropoietin and renal transplantation

The advent of erythropoietin (rHuEPO) has revolutionized the treatment of anemia in end-stage renal disease. While many studies indicate beneficial effects of rHuEPO in hemodialysis, peritoneal dialysis and predialysis patients, the impact of the drug in renal transplantation is less clear. Treatment with rHuEPO may reduce the degree of allosensitization produced by random blood transfusion while still allowing the possibility of the transplant survival benefit derived from deliberate transfusion. Recovery from anemia post-transplantation is hastened by treatment with rHuEPO, while patients with failing allografts respond to rHuEPO in a fashion similar to dialysis patients, despite the concomitant use of immunosuppressives. The erythropoietic response to rHuEPO is abrogated during episodes of acute rejection, and restored when successful treatment of rejection has occurred. Iron therapy is a critical factor for support of erythropoiesis and prevention of absolute iron deficiency posttransplantation. In patients presenting for renal transplant, the balance of evidence suggests that there is no increase in the rate of delayed graft function, graft loss or vascular thrombosis for patients who had received prior rHuEPO therapy.