Anemia After Renal Transplantation: An Underestimated Problem

Postrenal transplant anemia and its effects on patients and graft outcomes: Seven years follow-up

Introduction

Post-transplant anemia (PTA) is a common serious complication following kidney transplantation. It affects graft and patient survival. Anemia that presents within six months post-transplantation is defined as an early PTA. Late PTA is when anemia occurs more than six months following transplantation. Despite this, there are limited studies on the long-term impact of anemia on patient survival and graft function in kidney transplants. We conducted a retrospective study with long-term follow-up to investigate the effect of early and late PTA on patient and graft function within seven years and to estimate the prevalence of PTA at six months, two, four, and seven years postrenal transplantation along with the associated risk factors.

Method

A retrospective chart review of 145 adult patients who had kidney transplants from January 1 to December 31, 2015, and were followed up until December 31, 2022. Anemia was defined according to the World Health Organization (WHO) criteria of hemoglobin<12 gm/dl in females and<13 mg/dl in males. Pretransplant, six months, two, four, and seven years postrenal transplantation medications and laboratory data were obtained. Patients were excluded if they were pediatrics or had missing data.

Result

180 patients were screened, and 145 patients met the inclusion criteria. The prevalence of early PTA was 8.3%. Trimethoprim-sulfamethoxazole was significantly associated with anemia within six months. The prevalence of anemia increased at two, four-, and seven-years post-transplant (24.8%, 24.8%, and 27.6%, respectively). Graft failure was significantly associated with late PTA at four and seven years (p-value < 0.001). P < 0.005, respectively). Death was reported for 3 patients, and it was significantly associated with late transplant anemia (p-value < 0.005), Cytomegalovirus was associated with anemia at 6 months and 2 years post-transplant and significantly associated with graft failure (p-value < 0.037).

Conclusion

The results of this study indicate that post-transplant anemia is associated with graft failure and patient mortality. Therefore, managing anemia post-transplant should be addressed more carefully.

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.

Posttransplant Anemia as a Prognostic Factor of Mortality in Kidney-Transplant Recipients

Background. Findings on the association between posttransplant anemia (PTA) and mortality in posttransplant patients are scarce. This study explored whether PTA shortly after kidney transplantation (KT) predicts mortality at up to 10 years' follow-up, stratified for chronic kidney disease (CKD) stages. Methods. PTA was divided into 3 categories according to the hemoglobin (Hb) value: severe (Hb < 10 g/dl), mild (10.0 g/dl ≤ Hb < 11.9 g/dl), or no PTA (Hb ≥ 12 g/dl). CKD stages were estimated using the CKD-EPI formula and divided into 2 groups: CKD1-2 and CKD3-5. Cox regression, stratified according to CKD, was performed to identify whether different categories of PTA predicted mortality in KT recipients. Results. Age, being female, and both mild and severe PTA contributed significantly to the Cox regression model on mortality in CKD1-2. In the Cox regression model for mortality in CKD3-5, age and severe PTA contributed significantly to this model. Conclusion. PTA shortly after KT increased the risk of mortality at up to 10 years' follow-up. Even mild PTA is associated with a 6-fold higher risk of mortality and severe PTA with a 10-fold higher risk of mortality in CKD1-2. Clinical evaluation and treatment of anemia might reduce the higher risk of mortality in patients with PTA in early stages of CKD after KT.

The pre-transplant anemic condition is independent of long-term outcome in living-related kidney transplantation

The relationship between pre-transplant Hemoglobin (Hb) concentration and long-term outcome of living-related kidney transplantation is far from well addressed. A retrospective cohort study was conducted by reviewing the medical profile of the patients who received living-related kidney transplantations at our center from January 2006 to January 2013. Patients were divided into two groups: high Hb group (≥10 g/dL) and low Hb group (<10 g/dL). Cox regression model was utilized to analyze the effect of pre-transplant hemoglobin concentration on the patient and graft survival. About 422 patients were of Hb level <10 g/dL (78.30 ± 14.18 g/dL), 280 were >10 g/dL (116.2 ± 14.43 g/dL) (p < 0.001). In a follow-up of 35.34 ± 18.12 months, we did not find any difference in serum creatinine between the two groups. Low Hb concentration is not associated with increased risk of developing DGF (HR = 1.186, 95% CI: 0.53-2.654), acute rejection (HR = 1.338, 95% CI: 0.919-1.947), overall infection (HR = 1.263, 95% CI: 0.847-1.885) nor perioperational infection (HR = 1.019, 95% CI: 0.513-2.026). Though we detected a trend that low Hb level group were of higher incidence of patient death and graft failure, the two groups did not differ significantly (2.38% vs. 0.71%, p = 0.096; and 4.04% vs. 2.14%, p = 0.165, respectively). Cox regression model revealed that pre-transplant Hb level <10 g/dL was independent of increased overall mortality (HR = 3.379; 95% CI: 0.706-17.172) and increased death censored allograft failure risk (HR = 1.556; 95% CI: 0.595-4.069). Pre-transplant Hb concentration <10 g/dL is independent of poor long-term outcome of living-related kidney transplantation.

Prevalence and management of post-transplant anemia in long-term follow-up of Chinese kidney transplant recipients: a single-center report

BACKGROUND

Post-transplant anemia (PTA) has long been a less-recognized complication in kidney transplant recipients, and its prevalence also tends to be underestimated. This study sought to evaluate the prevalence, management, and risk factors of PTA from a group of long-term follow-up Chinese kidney transplant recipients.

METHODS

One hundred and fifty-four adult kidney transplant recipients were followed up at Fuzhou General Hospital, China, and retrospectively studied.

RESULTS

PTA prevalence at transplant and at 5-yearly time points after transplantation were 45.5%, 10.7%, 9.6%, 14.8%, 13.5%, and 19.6%, respectively. Overall, 38.3% of patients had been anemic at least once during the follow-up period, and 42% of these patients had recurrent anemia. Correlation analysis indicated that hemoglobin levels were associated with graft function. No correlations between anemia and age, gender, immunosuppressive regimens, or antihypertensive agents were observed. Binary logistic regression analysis suggested that serum creatinine and blood urea nitrogen were associated with the diagnosis of anemia at 1 year post-transplant. At 5 years post-transplant, only serum creatinine concentrations correlated with anemia. Although iron drugs are frequently used, erythropoietin was rarely administered in those anemic patients suffering poor graft function that necessitated such therapies.

CONCLUSIONS

The prevalence of PTA is noticeably high, and impaired kidney graft function seemed to be the major risk factor for anemia. There is an urgent need to improve current PTA management and to establish modified guidelines for this common complication in kidney transplant recipients.

Blood disorders after kidney transplantation

Post transplant anemia (PTA) is a common issue in kidney transplant recipients. Most importantly it is associated with an impaired allograft function. Other important factors associated with PTA are immunosuppressive drugs (MPA, AZA and SRL), iron deficiency, infections (Parvo B19), older donor age, rejection episodes, an increased inflammatory state, and erythropoietin hyporesponsiveness. As there are no adequately powered RCTs in the kidney transplant population on anemia treatment with ESA, we have to rely on what we know from the large RCTs in the CKD population. The recently published KDIGO guidelines do not recommend treatment with ESA if Hb is >10 g/dl. Repletion of iron stores is emphasized. Post transplant leukopenia (PTL) and thrombocytopenia (PTT) are frequent complications especially in the first six months after kidney transplantation. Myelosuppression caused by immunosuppressive agents (MPA, AZA, SRL, rATG), antimicrobial drugs (VGCV), and CMV infection is the predominant cause. There are no widely accepted guidelines on treatment strategies, but most often dose reduction or discontinuation of causative medication is done. Most clinicians tend to decrease MPA dose, but this is eventually associated with an increase in acute rejection episodes. VGCV dose reduction (preemptive treatment instead of CMV prophylaxis) may be a successful strategy. In severe cases G-CSF treatment is an important management option and seems to be safe.

Effect of mycophenolate mofetil on hematological side effects incidence in renal transplant recipients

Mycophenolate mofetil (MMF), an immunosuppressant administered after solid organ transplantation, is generally well tolerated; however, it frequently causes hematological toxicity. In this study, we aimed to assess the relation between the pharmacokinetic parameters of MMF metabolites (mycophenolic acid [MPA] and 7-O-MPA glucuronide [MPAG]) and the adverse effects on the hematopoietic system in renal transplant recipients. The four-h pharmacokinetic profiles of MPA and MPAG were determined using the HPLC method for MMF-treated patients (n = 61) among 106 renal transplant recipients (during the late post-transplant period) participating in the study. Anemia was more frequently observed in the study group compared with the control group (30.7% vs. 20.0%) and although the difference was insignificant, plasma iron concentrations were significantly higher in patients treated with MMF (32.9 ± 9.4 μmol/L vs. 28.7 ± 9.4 μmol/L; p = 0.032). Iron supplementation was more frequently applied to patients with anemia (48.2%) compared with patients with hemoglobin within the norm (20.3%; p = 0.005). As all MPAG pharmacokinetic parameters correlated negatively with hemoglobin and hematocrit, and MPAG pharmacokinetic parameters were higher in patients with anemia, MPAG may be the predicting factor of MMF side effects. In renal transplant recipients, especially with deteriorated renal function, extensive iron supplementation may be ineffective as anemia was associated with declined renal function and was not caused by low iron concentration.

Treatment of anemia with erythropoietin-stimulating agents in kidney transplant recipients and chronic kidney disease-another drawback of immunosuppression?

Anemia is more prevalent in allograft recipients compared with glomerular filtration rate (GFR) matched patients with chronic kidney diseases. There is a paucity of data concerning the correction of anemia in the posttransplant period with erythropoietin-stimulating agents (ESA). The aim of this study was to compare the iron status, kidney function, inflammatory state, use of drugs affecting erythropoiesis (immunosuppressants ACEi/ARB) and correction of anemia using ESA in a chronic kidney disease (CKD) population versus kidney transplant recipients. We included 67 patients treated with ESA including 17 after kidney transplantation. CKD Patients with native kidneys were significantly older than allograft recipients (mean age 69 versus 51 years; P < .001, and despite similar serum creatinine and iron parameters showed an estimated lower GFR (19 mL/min versus 23 mL/min; P < .05). Median time of ESA therapy was similar among patients with native kidney CKD versus kidney recipients, but they achieved a significantly higher hemoglobin (11.04 versus 10.36 g/dL; P < .05). There was no difference between patients administered or not a mammalian target of rapamycin antagonist. None of the patients with native kidney CKD received immunosuppressive therapy, but they were prescribed ACEi more often than kidney recipients. The higher degree of anemia in kidney allograft recipient is the most probably attributed to the use of immunosuppressive drugs, despite their better kidney function and comparable iron status. This study suggested that higher doses of ESA should be employed to anemia in kidney transplant recipients.

Understanding renal posttransplantation anemia in the pediatric population

Advances in renal transplantation management have proven to be beneficial in improving graft and patient survival. One of the properties of a well-functioning renal allograft is the secretion of adequate amounts of the hormone erythropoietin to stimulate erythropoiesis. Posttransplantation anemia (PTA) may occur at any point in time following transplantation, and the cause is multifactoral. Much of our understanding of PTA is based on studies of adult transplant recipients. The limited number of studies that have been reported on pediatric renal transplant patients appear to indicate that PTA is prevalent in this patient population. Erythropoietin deficiency or resistance is commonly associated with iron deficiency. An understanding of the risk factors, pathophysiology and management of PTA in the pediatric renal transplant population may provide guidelines for clinicians and researchers in the pursuit of larger prospective randomized control studies aimed at improving our limited knowledge of PTA. Recognition of PTA through regular screening and evaluation of the multiple factors that may contribute to its development are recommended after transplantation.

Anemia and erythrocytosis in patients after kidney transplantation

Anemia is a highly prevalent disorder in recipients of renal allografts. Despite its frequent occurrence, there is still uncertainty with regard to treatment targets and treatment options. This includes questions on appropriate iron management, the choice and dosage of erythropoietin stimulating agents, criteria for the timing of treatment initiation and the targeted hemoglobin values. The review summarizes available data on recent therapeutic strategies for post transplant anemia, as well as for post transplant erythrocytosis, another hematological disorder, that has decreased in recent years.

Effect of mycophenolate mofetil on plasma bioelements in renal transplant recipients

The proper concentrations of plasma bioelements may favorably reduce the incidence of metabolic disorders, which often occur during immunosuppressive therapy. Mycophenolate mofetil (MMF) is currently one of the most frequently administered immunosuppressive agents; however, MMF treatment is often related to gastrointestinal side effects. The aim of this study was thus to verify whether the MMF treatment itself, or its metabolite pharmacokinetics, has an effect on the concentrations of plasma bioelements. To determine this, the effect of MMF on the levels of both major (sodium [Na], potassium [K], calcium [Ca], magnesium [Mg]), and trace (iron [Fe], zinc [Zn], copper [Cu]) plasma bioelements in 61 renal transplant recipients was assessed in comparison to a control group (n = 45). The pharmacokinetic parameters of mycophenolic acid were determined by the high-performance liquid chromatography method. All patients filled out a 24-h diet history questionnaire. The results showed high plasma concentrations of Fe and low plasma concentrations of Mg and Zn as compared with diagnostic norms. The patients treated with MMF had significantly lower plasma Na (P < 0.001) and significantly higher plasma Zn (P = 0.030) and Cu concentrations (P < 0.001). In conclusion, MMF treatment was found to affect plasma Fe, Zn, and Cu levels by increasing their concentrations while decreasing the plasma Na concentration. Mg and Zn deficiencies, as well as excessive Fe levels, are frequently observed irrespective of the immunosuppressive regimen applied, which suggests that monitoring of these bioelements may be favorable.

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.

Prevalence and predictive factors of anemia after renal transplantation: a Moroccan report

OBJECTIVE

Anemia, a common multifactorial problem in kidney transplant recipients, represents an important cardiovascular risk factor. The purpose of this study was to assess anemia prevalence after kidney transplantation, the main factors involved in its occurrence, its cardiovascular consequences, and its impact on patient survival and graft function.

METHODS

This retrospective study evaluated 69 patients undergoing renal transplantation between January 1998 and September 2008 with ≥1 year of follow-up. For all of the patients, we recorded hemoglobin concentrations before and at 1, 3, 6, 12, 36, and 60 months after transplantation. Anemia was defined as recommended by the American Society of Transplantation: hemoglobin level <12 g/dL in women and <13 g/dL in men. To determine the factors involved in anemia occurrence, we compared 2 groups of patients, with versus without anemia, at various times after renal transplantation.

RESULTS

This study showed a high prevalence of anemia in the early posttransplantation period of 82.7% and 42% of kidney transplantation patients at 1 month and 6 months, respectively. It was mainly related to a low pretransplant hemoglobin level. The prevalence declined to 37.7% at 1 year. Renal graft dysfunction was the most important factor in the occurrence of late post-renal transplantation anemia. The presence of anemia increased the risk of renal graft functional deterioration by a factor of 2.9. The decreased prevalence at 1 year after transplantation was significantly associated with a reduction in left ventricular hypertrophy.

CONCLUSION

The management of anemia is essential to improve renal graft survival, reduce cardiovascular morbidity, and ensure a better quality of life for renal transplant recipients.

Genetic determinants of mycophenolate-related anemia and leukopenia after transplantation

BACKGROUND

Mycophenolate-related anemia and leukopenia are well-known toxicities after transplantation. Toxicity leads to dose reduction, addition of colony-stimulating factors or erythropoietin, or discontinuation of immunosuppressive therapy. The causes of and risk factors associated with toxicity are unclear.

METHODS

We studied the association between mycophenolate-related anemia and leukopenia and 2724 single nucleotide polymorphisms (SNP) in 978 patients undergoing living or deceased donor kidney transplant. Patients were followed up to time of first anemia (hemoglobin<10 gm/dL or hematocrit<30%) or first leukopenia (white blood cell [WBC] count <3000 cells/mm), which required clinical intervention in the first 6 months after transplant.

RESULTS

Anemia occurred in 87 (9.5%) subjects and leukopenia in 224 (22.9%). In single SNP analyses, none of the SNPs were associated with time to leukopenia at a false discovery rate (FDR) of 20%. However, SNPs from the IL12A, HUS, CYP2C8 genes were associated with time to anemia, allowing for an FDR of 20%. To assess the independence of these SNPs as predictors of anemia, we conducted a multi-SNP analysis including one SNP from each of the three genes. All three SNPs were associated with time to anemia, after adjusting for recipient age, weight, posttransplant dialysis and antiviral drug use, and stratifying by clinical center.

CONCLUSION

Although these SNPs require validation in an independent population, our results suggest that genetics may play a role in risk of mycophenolate-related hematologic toxicity. This may ultimately provide for better management of maintenance immunosuppression and gives insights into potential mechanism(s) by which toxicity occurs.

Cause of death with graft function among renal transplant recipients in an integrated healthcare system

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of death in renal transplant recipients with a functioning allograft. Modification of CVD risk factors may, therefore, decrease overall mortality in this patient population. We studied renal transplant recipients within an integrated healthcare system (IHS) that uses case management and electronic health records to determine mortality from CVD.

METHODS

We retrospectively collected data on all renal transplant recipients over a 10-year period. The primary endpoint was death with graft function (DWGF). Cardiovascular events were used as secondary endpoints. We determined the cause of death and collected laboratory data. The data were analyzed using Student's t test for continuous data, chi square for categorical data, and multivariate logistic regression. Survival was determined using the Kaplan-Meier product-limit method.

RESULTS

Death from "other" causes accounted for 29%. This was followed by CVD (24%), infection (16%), and malignancy (12%). The most common "other" causes were diabetes mellitus and end-stage renal disease. Overall, lower hemoglobin, uncontrolled blood pressure, and lower albumin levels were associated with DWGF. There were 184 cardiovascular events in total. Low-density lipid levels were lower in the group with cardiovascular events and DWGF. The use of antihypertensive and antihyperlipidemic agents was similar between the two groups with the exception of diuretics, which were used more often in the DWGF group.

CONCLUSIONS

There was a low rate of DWGF because of CVD within this IHS. It is possible that coordinated care within an IHS leads to improved cardiovascular mortality.