Negative Impact of One-Year Anemia on Long-Term Patient and Graft Survival in Kidney Transplant Patients Receiving Calcineurin Inhibitors and Mycophenolate Mofetil

A systematic review and meta-analysis of factors contributing to post-kidney transplant anemia and the effect of erythropoietin-stimulating agents

BACKGROUND

The effects of various risk and associated factors on post-kidney transplant anemia (PTA) have not been fully compared and estimated. This meta-analysis aims to elucidate factors contributing to PTA and determine the influence of erythropoietin-stimulating agents (ESAs) on renal outcomes, thus offering potential pathways for enhanced management strategies post-transplant.

METHODS

A systematic review was conducted in electronical database. Studies reporting on risk factors (with cause-effect relationships) and associated factors (without definite cause-effect relationships) of PTA, and the effects of ESAs on post-kidney transplant outcomes, were included. Pooled odds ratios (ORs) and weighted mean differences (WMDs) were analyzed using random-effects models.

RESULTS

This systematic review encompassed 38,233 patients from 85 studies. Factors increased PTA risk included African American, older donor age, human antigen leukocyte mismatches, and low pre-transplant hemoglobin levels. Poor allograft function, high interleukine-6, Cytomegalovirus, delayed graft function, allograft rejections, immunosuppressive medications, and renin-angiotensin system blockades were associated with PTA. Native autosomal dominant polycystic kidney disease was a protective factor against PTA. Administration of ESAs with the aim of normalizing hemoglobin levels in patients with chronic allograft dysfunction slowed the decline in eGFR and reduce the risk of death, with a pooled OR of 0.36 (95% CI: 0.14 to 0.89; p = 0.040).

CONCLUSIONS

The risks and associated factors for PTA have been elucidated, underscoring the need for individualized treatment approaches. Late ESA therapy, aimed at hemoglobin normalization, suggests a renal-protective effect and reduced mortality, which should be considered in the management of PTA.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024545330.

Post kidney transplant hematologic abnormalities and association of post-transplant anemia with graft function

Background

Haematological abnormalities following renal transplantation are frequently observed and have a significant effect on survival and graft outcomes. The pattern of haematological abnormalities varies globally. Few studies have been conducted in Asian countries. We aimed to evaluate the patterns of haematological abnormalities in post-transplant recipients in our center during the first year after post-renal transplant and the association of post-transplant anemia with graft function.

Methods

This single-center retrospective study was conducted on renal transplantation recipients between 2014 and 2019. The study included all patients who received kidney transplants from live/cadaveric donors and had follow-up data collected up to 12 months after the transplant. The outcome studied was the prevalence of haematological abnormalities and the association between post-transplant anemia (PTA) and graft function in post-transplant recipients.

Results

A total of 106 renal transplant recipients were included in the study. The prevalence of PTA was 98% in the first week, 75% at one month, 35% at three months, 32% at six months, and 27% at 12 months. The other cytopenia cases were leukopenia (43.4%), thrombocytopenia (33.2%), and pancytopenia (15.1%). Post-transplant erythrocytosis was observed in 17.9% of patients. 18 patients with severe PTA in the first week of transplant had significant allograft dysfunction (p=0.04). Patients with and without PTA had similar graft functions at six and 12 months (p=0.50).

Conclusions

Haematological abnormalities are common in renal transplant recipients. PTA is highly prevalent during the first week and improves over time. Other haematological abnormalities observed were leukopenia, thrombocytopenia, pancytopenia, and post-transplant erythrocytosis. Leucopenia was primarily drug-induced, and thrombocytopenia and pancytopenia were frequently caused by infections in our cohort. Additionally, severe PTA was significantly associated with graft dysfunction in the first week post-transplant, whereas similar graft function was observed at 6 and 12 months post-transplant, irrespective of the presence or absence of PTA.

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.

Factors associated with anaemia in kidney transplant recipients in the first year after transplantation: a cross-sectional study

Background

Anaemia after kidney transplantation may reduce quality of life, graft or patient survival. We aimed to determine the prevalence and risk factors for anaemia in the initial 12 months after transplantation.

Methods

We conducted a cross-sectional study at 6 and 12 months after transplantation. Anaemia was defined by World Health Organization criteria taking into consideration erythropoietin use. Logistic regression was used to determine the association between demographic, clinical and pharmacological risk factors for the main outcome of moderate-severe anaemia.

Results

A total of 336 transplant recipients were included and the prevalence of moderate-severe anaemia was 27.4% at 6 months and 15.2% at 12 months. Lower kidney function, female gender, transferrin saturation below 10% and proteinuria were associated with moderate-severe anaemia at both time points. Recent intravenous immunoglobulin treatment was associated with anaemia at 6 months. Recent infection and acute rejection were also associated with anaemia 12 months. Around 20% of patients had at least one blood transfusion but they were uncommon beyond 3 months.

Conclusions

Anaemia remains highly prevalent requiring treatment with erythropoietin and transfusions. Most identifiable risk factors relate to clinical problems rather than pharmacological management, while markers of iron-deficiency remain difficult to interpret in this setting.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1054-7) contains supplementary material, which is available to authorized users.

The impact of time-varying clinical surrogates on disparities in African-American kidney transplant recipients - a retrospective longitudinal cohort study

An improved understanding of the impact of clinical surrogates on disparities in African-American (AA) kidney transplantation (KTX) is needed. We conducted a 10-year retrospective longitudinal cohort study of electronically abstracted clinical data assessing the impact of surrogates on disparities in KTX. Clinical surrogates were assessed by posttransplant year (1, 2, 3 or 4) and defined as acute rejection (Banff ≥1A), mean SBP >140 mmHg, tacrolimus variability (CV) >40%, mean glucose >160 mg/dl and mean hemoglobin <10 g/dl. We utilized landmark methodology to minimize immortal time bias and logistic and survival regression to assess outcomes; 1610 KTX were assessed (54.2% AAs), with 1000, 468, 368 and 303 included in the year 1, 2, 3 and 4 complete case analyses, respectively. AAs had significantly higher odds of developing a clinical surrogate, which increased in posttransplant years three and four [OR year 1 1.99 (1.38-2.88), year 2 1.77 (1.20-2.62), year 3 2.35 (1.49-3.71), year 4 2.85 (1.72-4.70)]. Adjusting for the five clinical surrogates in survival models explained a significant portion of the higher risks of graft loss in AAs in post-transplant years three and four. Results suggest focusing efforts on improving late clinical surrogate management within AAs may help mitigate racial disparities in KTX.

Association between anemia at three different time points and new-onset diabetes after kidney transplantation--a retrospective cohort study

PURPOSE

Anemia has been reported to be associated with diabetes, but the association between new-onset diabetes after transplantation (NODAT) and anemia has not been reported.

METHODS

Patients who underwent kidney transplantation and did not have diabetes prior to transplantation were included in this study. Hemoglobin levels and the prevalence of anemia (hemoglobin <12 g/dL in females and <13 g/dL in males) were evaluated at three time points (prior to transplantation, 6 months following transplantation or 1 month before the development of NODAT, 2 years following transplantation, or following the development of NODAT) and were compared between those who developed NODAT and those who did not. Variables associated with the development of anemia were compared between the two groups.

RESULTS

A total of 266 kidney transplant recipients were included, of which 71 (27%) developed NODAT during the time of the follow-up. Hemoglobin and hematocrit levels and the prevalence of anemia were similar in those with and without NODAT at all three time points evaluated. Ferritin levels, prior to transplantation and mean corpuscular volume (MCV) posttransplantation post-NODAT development, were slightly but significantly lower in those with NODAT, although both were within the normal range.

CONCLUSIONS

Pretransplantation ferritin levels and posttransplantation post-NODAT development MCV are inversely associated with the development of NODAT in kidney transplants.

Kidney transplantation in Romania: two transplant centers experience

PURPOSE

Kidney graft survival rates improved from decade to decade, but data about factors that affect patient and graft survival remain challenging and even controversial.

METHODS

We analyzed retrospectively data from kidney transplanted patients followed in two Romanian transplant centers (Iasi and Bucharest)-new programmes specifically developed after 1989 to cover transplantation requirements for two-thirds of Romania. We used a composite survival outcome defined as 50% reduction in estimated glomerular filtration rate (eGFR), return to dialysis or death. Survival analysis was performed using uni- and multivariable Cox regression with baseline and time-updated covariates.

RESULTS

From the entire cohort of 365 patients, 243 had the outcome of interest. In the univariable Cox survival analysis, age, hemoglobin, eGFR, cholesterol, AST and transplant center were associated with the outcome. The multivariable Cox analysis reveals that only cholesterol (HR 0.97, 95% CI 0.94-0.99 per 10 mg/dL increase) and transplant center (HR 3.64, 95% CI 2.67-4.97) remain associated. For the time-updated Cox survival analysis we found that eGFR (HR 0.91, 95% CI 0.87-0.96 per 10 ml/min/1.73 m² increase) and cholesterol are associated with the outcome in the univariable analysis and only eGFR and transplant center in the multivariable Cox survival analysis.

CONCLUSIONS

Our study reports data from two distinct transplant centers from a developing country. Our results are similar to the current literature data, but also reveal that the approach of a center to the transplantation management is an independent factor associated with graft survival.

Strategies for long-term preservation of kidney graft function

Kidney transplantation has become a routine procedure in the treatment of patients with kidney failure, and requires collaboration of experts from different disciplines, such as nephrology, surgery, immunology, pathology, infectious disease medicine, cardiology, and oncology. Grafts can be obtained from deceased or living donors, with different logistical requirements and implications for long-term graft patency. 1-year graft survival rates are greater than 95% in many centres but improvement of long-term function remains a challenge. New developments in molecular immunology and computational biology have increased precision of donor and recipient matching of HLA and non-HLA compatibility. Individual omics-wide molecular diagnostics, extracorporeal therapies, and drug developments allow for precise individual decision making and treatment. Tolerance induction by mixed chimerism without toxic conditioning and with a low risk of graft versus host disease is a visionary but realistic goal. Some of these innovations are already used in modern transplant centres and will allow advancement in long-term allograft preservation.

Anemia and low-grade inflammation in pediatric kidney transplant recipients

BACKGROUND

Anemia and low-grade inflammation are reported to be associated with impaired long-term graft outcome in renal transplant (RTx) recipients. In this study, hemoglobin (Hb) and inflammation marker levels were correlated with measured glomerular filtration rate (GFR) in 128 pediatric RTx recipients over a median follow-up period of 10 years.

METHODS

Serum levels of erythropoietin (EPO), hepcidin-25, high-sensitivity C-reactive protein (CRP) (hsCRP) and interleukin-6 (IL-6) were analyzed by enzyme-linked immunosorbent assays, and GFR was analyzed by ⁵¹Cr-EDTA clearance.

RESULTS

The median levels of Hb (115 g/L), hsCRP (0.4 mg/L) and IL-6 (1.4 pg/mL) and the median erythrocyte sedimentation rate (ESR; 19 mm/h) remained stable after the first post-operative year. However, approximately half of the patients had a normocytic, normochromic anemia, and one-third had elevated levels of hsCRP (>1 mg/L) and ESR (>25 mm/h), indicating continuous low-grade inflammation. Low Hb levels preceded increased fibrosis in protocol biopsies taken at 1.5 and 3 years after transplantation and preceded decreased GFR by several years. Hb levels showed an inverse correlation with EPO levels (r = -0.206, p = 0.038) and ESR (r = -0.369, p < 0.001), but not with hepcidin-25, hsCRP or IL-6 levels. The levels of the major inflammatory markers IL-6 and hsCRP did not show a significant correlation with GFR at either the early maintenance phase or later. In the multivariable analysis, low Hb levels performed better than any other marker with respect to predicting concomitant and subsequent GFR.

CONCLUSIONS

Anemia, but not elevated inflammatory indices, was associated with poor concomitant and subsequent graft function during a 10-year follow-up in pediatric RTx patients.

Erythropoiesis stimulating agents and reno-protection: a meta-analysis

Background

Erythropoiesis stimulating agents (ESAs) were proposed to enhance survival of renal tissues through direct effects via activation of EPO receptors on renal cells resulting in reduced cell apoptosis, or indirect effects via increased oxygen delivery due to increased numbers of Hb containing red blood cells. Thus through several mechanisms there may be benefit of ESA administration on kidney disease progression and kidney function in renal patients. However conflicting ESA reno-protection outcomes have been reported in both pre-clinical animal studies and human clinical trials. To better understand the potential beneficial effects of ESAs on renal-patients, meta-analyses of clinical trials is needed.

Methods

Literature searches and manual searches of references lists from published studies were performed. Controlled trials that included ESA treatment on renal patients with relevant renal endpoints were selected.

Results

Thirty two ESA controlled trials in 3 categories of intervention were identified. These included 7 trials with patients who had a high likelihood of AKI, 7 trials with kidney transplant patients and 18 anemia correction trials with chronic kidney disease (predialysis) patients. There was a trend toward improvement in renal outcomes in the ESA treated arm of AKI and transplant trials, but none reached statistical significance. In 12 of the anemia correction trials, meta-analyses showed no difference in renal outcomes with the anemia correction but both arms received some ESA treatment making it difficult to assess effects of ESA treatment alone. However, in 6 trials the low Hb arm received no ESAs and meta-analysis also showed no difference in renal outcomes, consistent with no benefit of ESA/ Hb increase.

Conclusions

Most ESA trials were small with modest event rates. While trends tended to favor the ESA treatment arm, these meta-analyses showed no reduction of incidence of AKI, no reduction in DGF or improvement in 1-year graft survival after renal transplantation and no significant delay in progression of CKD. These results do not support significant clinical reno-protection by ESAs.

Clinical Course and Outcomes of Late Kidney Allograft Dysfunction

Background. This study is provided to increase the efficiency of the treatment of kidney transplant recipients by predicting the development of the late allotransplant dysfunction. Methods. 330 patients who have lived for more than one year with functioning kidney allograft were evaluated. To predict the subsequent duration of the well-functioning of allotransplant the prognostic significance of 15 baseline clinical and sociodemographic characteristics on the results of the survey one year after transplantation was investigated. The result was considered to be positive in constructing the regression prognostication model if recipient lived more than 3 years from the time of transplantation. Results. It was established that more late start of renal allograft dysfunction after transplantation correlates with the more time it takes till complete loss of allograft function. Creatinine and hemoglobin blood concentration and the level of proteinuria one year after transplantation within created mathematical model allow predicting the loss of kidney transplant function three years after the transplantation. Patients with kidney transplant dysfunction are advised to renew the program hemodialysis upon reaching plasma creatinine concentration 0.5–0.7 mmol/L. Conclusion. Values of creatinine, hemoglobin, and proteinuria one year after transplantation can be used for subsequent prognostication of kidney transplant function.

Managing Cardiovascular Risk in the Post Solid Organ Transplant Recipient

Solid organ transplantation is an effective treatment for patients with end-stage organ disease. The prevalence of cardiovascular diseases (CVD) has increased in recipients. CVD remains a leading cause of mortality among recipients with functioning grafts. The pathophysiology of CVD recipients is a complex interplay between preexisting risk factors, metabolic sequelae of immunosuppressive agents, infection, and rejection. Risk modification must be weighed against the risk of mortality owing to rejection or infection. Aggressive risk stratification and modification before and after transplantation and tailoring immunosuppressive regimens are essential to prevent complications and improve short-term and long-term mortality and graft survival.

Post-transplantation Anemia Predicts Cardiovascular Morbidity and Poor Graft Function in Kidney Transplant Recipients

OBJECTIVE

We aimed to investigate whether low post-transplantation-period hemoglobin levels are predictive of cardiovascular morbidity in terms of left ventricular (LV) hypertrophy and vascular stiffness and to determine the contributing factors of post-transplantation anemia in kidney transplant (KT) recipients.

METHODS

One hundred fifty (mean age, 38.9 ± 10.8 y; 113 male) KT recipients with functioning grafts were enrolled in the study. All subjects underwent clinical and laboratory evaluations (24-hour urinary protein loss, complete blood count) and transthoracic echocardiography to assess LV systolic function. Arterial stiffness was measured by means of carotid-femoral pulse-wave velocity (PWV). Mean hemoglobin levels were analyzed at the 1st, 6th, 12th, and 24th months after transplantation. Patients were divided into 2 groups according to presence of anemia: patients with anemia (group 1; n = 120) and normal (group 2; n = 30).

RESULTS

PWV values (6.8 ± 1.9 m/s vs 6.4 ± 1.1 m/s in groups 1 and 2, respectively; P = .002) and LV mass index (LVMI; 252.1 ± 93.7 g/m(2) vs 161.2 ± 38.5 g/m(2) groups 1 and 2, respectively; P = .001) were significantly higher in group 1. Estimated glomerular filtration rate and (64 ± 28.5 m/min vs 77.8 ± 30 m/min in groups 1 and 2, respectively; P = .001) LV systolic function (57.2 ± 5.8% vs 77.8 ± 30% in groups 1 and 2, respectively; P < .005) were significantly lower in group 1. In regression analysis, LV systolic function and LVMI were predictors of post-transplantation hemoglobin levels.

CONCLUSIONS

Post-transplantation anemia contributes to cardiovascular morbidity by deteriorating LV function and increasing PWV and is therefore associated with poor prognosis for graft survival. Early correction of post-transplantation anemia, especially with the use of erythropoietin, may be beneficial for both graft and recipient survivals.

Parameters influencing blood erythropoietin levels of renal transplant recipients during the early post-transplantation period

AIM

Renal transplantation is accompanied by restoration of renal function and endogenous erythropoietin production. The purpose of this study was to investigate the time-related changes of endogenous erythropoietin secretion in the early renal post-transplant period and the influence of various parameters to this process.

METHODS

Fifty-eight patients were enrolled in the study and followed up for 3 months after successful renal transplantation. Erythropoietin levels were measured at regular intervals and correlated with renal function, cold ischemia time and immunosuppressive regimen used.

RESULTS

Two peaks of serum erythropoietin levels were observed: an early peak that occurred within two days after transplantation and a late one, between weeks 2 and 4, which resulted in increased blood hemoglobin levels. Factors that were found to correlate with erythropoietin levels were delayed graft function, cyclosporine use and prolonged cold ischemia time. Serum creatinine did not correlate to erythropoietin levels although the reduction of serum creatinine preceded the rise of erythropoietin levels. Normal hemoglobin values were restored about three months after successful renal transplantation.

CONCLUSION

Serum erythropoietin levels increase during the early post-transplantation period resulting in correction of anemia three months after a successful renal transplantation. Restoration of allograft function is a prerequisite for erythropoietin secretion, while cold ischemia time and immunosuppressive regimen affect graft function.

Long-acting erythropoietin stimulating agents for persistent anemia after kidney transplant: risk factors and outcome

OBJECTIVES

Posttransplant anemia is associated with an increased risk of congestive heart failure, left ventricular hypertrophy, and death. The purpose of this study was to evaluate the effect of long-acting erythropoietin-stimulating agents on anemia after kidney transplant.

MATERIALS AND METHODS

In 2306 kidney transplant recipients, 250 anemic patients (11%) with stable graft function were followed at the Hamed Al-Essa Organ Transplant Centre (Kuwait) and were assessed for anemia. We enrolled 120 patients into this open-label study in 2 groups: group 1 had treatment with darbepoetin alfa (86 patients) and group 2 had continuous erythropoietin receptor activator (34 patients).

RESULTS

Patient age correlated negatively with serum iron level. Serum ferritin correlated negatively with hemoglobin level 6 months after transplant but not at time of transplant. Most patients were women who received their grafts from male donors. The 2 groups were comparable in frequency of rejection and mean hemoglobin and serum albumin levels at 3, 6, 9, and 12 months after transplant. There was no difference between the 2 groups in renal function (estimated glomerular filtration rate); posttransplant complications such as new-onset diabetes after transplant, hypertension, serious bacterial infections, or patient and graft outcomes.

CONCLUSIONS

Anemia is an important problem after kidney transplant, and iron use is suboptimal in kidney transplant recipients. Darbepoetin alfa and continuous erythropoietin receptor activator had comparable positive results.

Pharmacology and toxicology of mycophenolate in organ transplant recipients: an update

This review aims to provide an update of the literature on the pharmacology and toxicology of mycophenolate in solid organ transplant recipients. Mycophenolate is now the antimetabolite of choice in immunosuppressant regimens in transplant recipients. The active drug moiety mycophenolic acid (MPA) is available as an ester pro-drug and an enteric-coated sodium salt. MPA is a competitive, selective and reversible inhibitor of inosine-5'-monophosphate dehydrogenase (IMPDH), an important rate-limiting enzyme in purine synthesis. MPA suppresses T and B lymphocyte proliferation; it also decreases expression of glycoproteins and adhesion molecules responsible for recruiting monocytes and lymphocytes to sites of inflammation and graft rejection; and may destroy activated lymphocytes by induction of a necrotic signal. Improved long-term allograft survival has been demonstrated for MPA and may be due to inhibition of monocyte chemoattractant protein 1 or fibroblast proliferation. Recent research also suggested a differential effect of mycophenolate on the regulatory T cell/helper T cell balance which could potentially encourage immune tolerance. Lower exposure to calcineurin inhibitors (renal sparing) appears to be possible with concomitant use of MPA in renal transplant recipients without undue risk of rejection. MPA displays large between- and within-subject pharmacokinetic variability. At least three studies have now reported that MPA exhibits nonlinear pharmacokinetics, with bioavailability decreasing significantly with increasing doses, perhaps due to saturable absorption processes or saturable enterohepatic recirculation. The role of therapeutic drug monitoring (TDM) is still controversial and the ability of routine MPA TDM to improve long-term graft survival and patient outcomes is largely unknown. MPA monitoring may be more important in high-immunological recipients, those on calcineurin-inhibitor-sparing regimens and in whom unexpected rejection or infections have occurred. The majority of pharmacodynamic data on MPA has been obtained in patients receiving MMF therapy in the first year after kidney transplantation. Low MPA area under the concentration time from 0 to 12 h post-dose (AUC0-12) is associated with increased incidence of biopsy-proven acute rejection although AUC0-12 optimal cut-off values vary across study populations. IMPDH monitoring to identify individuals at increased risk of rejection shows some promise but is still in the experimental stage. A relationship between MPA exposure and adverse events was identified in some but not all studies. Genetic variants within genes involved in MPA metabolism (UGT1A9, UGT1A8, UGT2B7), cellular transportation (SLCOB1, SLCO1B3, ABCC2) and targets (IMPDH) have been reported to effect MPA pharmacokinetics and/or response in some studies; however, larger studies across different ethnic groups that take into account genetic linkage and drug interactions that can alter a patient's phenotype are needed before any clinical recommendations based on patient genotype can be formulated. There is little data on the pharmacology and toxicology of MPA in older and paediatric transplant recipients.

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.

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.

Haemoglobin variability in the early post-transplant period: association with graft survival and mortality

AIM

Haemoglobin (Hb) variability is associated with poor survival in patients with chronic kidney disease. Association of Hb variability after kidney transplantation with patients' and graft survival has not been adequetly studied.

METHODS

This retrospective study used registry data to examine the association between Hb variability in the early post-transplant period (first 6 months) and graft survival after kidney transplantatin. Kaplan-Meier and Cox regression analyses were used for univariate and multivariate associations between mortality, death censored graft survival and the composite outcome of both, in 752 patients after kidney transplantation. Hb values were collected each month during the first 6 months after transplantation, and Hb variavility was calculated using the residual standard deviation method.

RESULTS

The highest quartile of Hb variability was associated with inferior graft and patients' survival in univariate (hazard ratio (HR) 2.18; 95% confidence interval (CI) 1.51 to 3.13; P < 0.001) and multivariate models (HR 1.5; 95% CI 1.029 to 2.18; P = 0.035). This association was mainly due to increased death censored graft failure in the high variability group (HR 2.75; 95% CI 1.73 to 4.38; P < 0.001) and (HR 1.67; 95% CI 1.023 to 2.74; P = 0.04) in the univariate and multivariate models, respectively. There was no association between Hb variability and the risk of death (HR 1.51; 95% CI 0.88 to 2.57; P = 0.132).

CONCLUSION

High Hb variability is independently associated with inferior graft survival in patients after kidney transplantation.

Clinical profile and post-transplant anaemia in renal transplant recipients restarting dialysis after a failed graft: changing trends between 2001 and 2009

BACKGROUND

The aim of this study was to compare the clinical profile, outcome and the prevalence and management of anaemia between two cohorts of renal transplant patients with graft failure restarting dialysis in 2001 and 2009.

METHODS

Cross-sectional, observational, retrospective and multicentre study of 397 patients in the 2001 cohort and 222 in the 2009 cohort. Data were recorded at 0, 3, 6, 9 and 12 months before the onset of dialysis resumption and during the first 90 days after restarting dialysis (mortality and hospital admission).

RESULTS

Patients in the 2009 cohort were older at the time of inclusion in the study and transplantation, and restarted dialysis therapy with a significantly better glomerular filtration rate. In both cohorts, there was a rapid deterioration of renal function with statistically significant differences in serum creatinine and glomerular filtration rate between the monthly intervals -12 and 0. The mean haemoglobin value at -12 months was 11.6 g/dL [7.2 mmol/L] in the 2001 cohort when compared with 12.3 g/dL [7.6 mmol/L] in the 2009 cohort, and at the time of restarting dialysis 9.6 g/dL [6.0 mmol/L] versus 10.6 g/dL [6.6 mmol/L]. The percentage of patients treated with erythropoiesis-stimulating agents, at any time during the 12 months before readmission to dialysis, increased significantly from 61.5% in the 2001 cohort to 96% in the 2009 cohort. There were no significant differences between the 2001 and 2009 cohorts in mortality rate (8.8 versus 9.0%) or hospital admission (31.5 versus 31.1%) during the study time.

CONCLUSIONS

At restarting dialysis, the proportion of patients with anaemia (and its severity) due to progressive graft nephropathy decreased over the past 8 years, increasing significantly the percentage of patients treated with erythropoietin. Differences in morbimortality after dialysis resumption were not observed, this is probably due to an increase in the age of donors and recipients.

The nephroprotective properties of recombinant human erythropoietin in kidney transplantation: experimental facts and clinical proofs

Adaptive responses to hypoxia, including hypoxia-inducible factor signaling, allow the cell to satisfy its basal metabolic demand and avoid death, but these responses can also be deleterious by promoting inflammation, cell dedifferentiation and fibrogenesis. Therefore, targeting hypoxia constitutes a promising therapeutic avenue. Recombinant human erythropoietin (rhEPO) appeared as a good candidate therapy because its hematopoietic properties could reverse anemia, and its tissue-protective properties could reduce cell death and limit maladaptive cellular responses to hypoxia. Despite experimental evidence on the nephroprotecive properties of rhEPO, recent clinical trials provided evidence that rhEPO was ineffective in preventing delayed graft function after ischemic acute injury but that the normalization of hemoglobin values preserved kidney function deterioration and reduced graft loss. Our aim here is to provide a survey of the rationale for evaluating the administration of rhEPO in the setting of kidney transplantation. We will discuss the intriguing findings that emerged from the clinical trials and the discrepancies between promising experimental results and negative clinical studies, as well as the differences in terms of the benefits and safety profiles of the normalization of hemoglobin values in chronic kidney disease patients and kidney transplant patients.

Anemia at 1 year after kidney transplantation has a negative long-term impact on graft and patient outcomes

BACKGROUND

Anemia, a common complication after kidney transplantation, has a controversial impact on graft or patient survivals or the appearance of cardiovascular disease. The present study investigated the incidence and risk factors for anemia in the first year after transplantation and its effects on graft and patient outcomes.

PATIENTS AND METHODS

Among 389 patients transplanted between January 2000 and June 2008, the 331 with functioning grafts at 1 year were included in the study. The mean follow-up was 84 ± 31.8 months. Anemia was defined according to the World Health Organization as a hemoglobin < 13 g/dL in men and < 12 g/dL in women.

RESULTS

The 88 patients (26.6%) with anemia included 21 (6.3%) who were receiving erythropoiesis stimulant agents. The predictive factors for anemia were: initial immunosuppression with cyclosporine (odds ratio [OR] 2.08, 95% confidence interval [CI] 1.25-3.47; P = .005), serum creatinine (mg/dL) at discharge (OR 1.7; CI 95% 1.26-2.15 P = .000), and 1-year serum albumin (g/dL; OR 0.21; CI 95% 0.10-0.71 P = .001). Donor age in years (OR 1.02; CI 95% 1.00-1.03, P = .054) was close to significance. Cox multivariate analysis showed 1-year hemoglobin (g/dL) to be associated with graft (hazard ratio [HR] 0.81, 95% CI 0.69-0.96, P = .003) and patient survivals after adjusting for other variables (HR 0.74; 95% CI 0-59-0.96, P = .023). But it was only a cardiovascular risk factor when serum creatinine was not included in the model.

CONCLUSIONS

Approximately one quarter of patients with functioning grafts show anemia at 1-year. Graft function, initial immunosuppression, serum albumin, and perhaps donor age were risk factors for anemia, which had a negative impact on graft and patient survival, and could be a risk factor for cardiovascular disease.

The Janus faces of ESAs: caveat Chimaera!

Patients with chronic kidney disease (CKD) have a Janus quality as they look back whence they came in developing CKD and, in some cases, also look forwards to a potential kidney transplant with the attendant promise of improvement in quality and often quantity of life. Making the most of this often unique opportunity is key-maximising the chance that the engraftment starts as a success, and then later, preserving good kidney transplant function for as long as possible. Two recently published, independently conceived and executed studies are relevant to both aspects of this quest and thus to all kidney transplant recipients (KTRs). Both trials also simultaneously stoke and quench the continuing, heated debates over target haemoglobin (Hb) levels, and the use of erythropoiesis-stimulating agents (ESAs), in CKD patients. One study--of acute, high-dose ESA administration--adds to the plethora of adverse safety signals swirling around the use of ESAs while surprisingly also showing renal function benefits at 12 months. The other study features chronic lower-dose ESA use in stable KTRs with anaemia and impaired renal function and not only purports to show a salutary effect on 2-year renal function outcomes (and thus reducing "return to dialysis" rates), but also rebuts the now widely accepted current notion that by chronic use of ESAs to target full Hb correction/higher Hb values in anaemic CKD patients, we are potentially causing harm.

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.

Correction of postkidney transplant anemia reduces progression of allograft nephropathy

Retrospective studies suggest that chronic allograft nephropathy might progress more rapidly in patients with post-transplant anemia, but whether correction of anemia improves renal outcomes is unknown. An open-label, multicenter, randomized controlled trial investigated the effect of epoetin-β to normalize hemoglobin values (13.0-15.0 g/dl, n=63) compared with partial correction of anemia (10.5-11.5 g/dl, n=62) on progression of nephropathy in transplant recipients with hemoglobin <11.5 g/dl and an estimated creatinine clearance (eCrCl) <50 ml/min per 1.73 m(2). After 2 years, the mean hemoglobin was 12.9 and 11.3 g/dl in the normalization and partial correction groups, respectively (P<0.001). From baseline to year 2, the eCrCl decreased by a mean 2.4 ml/min per 1.73 m(2) in the normalization group compared with 5.9 ml/min per 1.73 m(2) in the partial correction group (P=0.03). Furthermore, fewer patients in the normalization group progressed to ESRD (3 versus 13, P<0.01). Cumulative death-censored graft survival was 95% and 80% in the normalization and partial correction groups, respectively (P<0.01). Complete correction was associated with a significant improvement in quality of life at 6 and 12 months. The number of cardiovascular events was low and similar between groups. In conclusion, this prospective study suggests that targeting hemoglobin values ≥13 g/dl reduces progression of chronic allograft nephropathy in kidney transplant recipients.

Association between gene polymorphisms of the components of the renin-angiotensin-aldosteron system, graft function, and the prevalence of hypertension, anemia, and erythrocytosis after kidney transplantation

INTRODUCTION

Genetic predisposition, including polymorphisms of the renin-angiotensin system (RAS) genes, are among the potential factors that may affect the occurrence of hypertension, anemia, or erythrocytosis as well as transplanted kidney function. However, the association of the RAS genes polymorphism and the kidney transplant outcomes is controversial. The aim of this study was to analyze the association between polymorphic variants of the angiotensin-converting enzyme (insertion/deletion [I/D]), angiotensinogen (M235T), and angiotensin II receptor type 1 (A1166C) genes, and the early and long-term kidney graft outcomes, as well as the prevalence of hypertension, anemia and erythrocytosis after kidney transplantation.

PATIENTS AND METHODS

We included 331 consecutive kidney transplant patients performed between 1998 and 2003. Of the total, 87.9% of patients completed a 5-year follow-up. Subjects were genotyped for the I/D, M235T, and A1166C polymorphisms.

RESULTS

None of the examined polymorphism affected early or long-term graft function or was associated with hypertension before or after kidney transplantation. There was no significant difference in genotype distribution between patients with and without posttransplant erythrocytosis. However, posttransplant anemia (PTA) seemed to be significantly more common among kidney recipients with TT and MT than MM angiotensinogen genotypes (35.7% vs 20.7%; P=.03). The T allele was associated with the risk of development of PTA (odds ratio, 2.12; 95% confidence interval, 1.12-3.99; P=.02).

CONCLUSION

Our results do not support the hypothesis that polymorphism of the genes coding RAS components may by an independent risk factor for the development of interstitial fibrosis/tubular atrophy, posttransplant hypertension, or PTE. Further studies are necessary to investigate the association between angiotensinogen M235T genotypes and 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.

Early risk factors for persistent anemia after kidney transplantation

STUDY OBJECTIVE

To identify predictors of persistent posttransplant anemia that appear within the first week after kidney transplantation in order to determine the high-risk patients who might receive the most benefit from erythropoiesis-stimulating agents.

STUDY DESIGN

Retrospective cohort study.

SETTING

University-affiliated hospital and outpatient clinic.

PATIENTS

One hundred sixty-four adult kidney transplant recipients (January 1, 2002-June 30, 2007) with anemia on posttransplant day 7 who were followed at the clinic for at least 2 months after transplantation.

MEASUREMENTS AND MAIN RESULTS

Data from deidentified electronic medical records of the kidney transplant recipients were collected and included demographic characteristics, primary cause of renal failure, pertinent laboratory data, and donor information. To detect early predictors of persistent anemia, patients with persistent posttransplant anemia, defined as a hemoglobin level below 11 g/dl for 2 months (day 60) after transplantation, were compared with those who had nonpersistent posttransplant anemia, defined as a hemoglobin level below 11 g/dl on day 7 but 11 g/dl or greater on day 60. Of the 164 patients classified as having anemia on posttransplant day 7, 39 (23.8%) had persistent posttransplant anemia on day 60. In univariate analyses, hemoglobin level of 9 g/dl or below on day 7, donor age younger than 10 years, and female sex were variables associated with increased risk of persistent posttransplant anemia. In a multivariate analysis, donor age younger than 10 years was the most significant predictor of persistent posttransplant anemia, followed by hemoglobin level of 9 g/dl or below.

CONCLUSION

Patients receiving transplants from donors younger than 10 years and those with hemoglobin levels of 9 g/dl or below on postoperative day 7 were found to be at highest risk for persistent posttransplant anemia and may receive the most benefit from early initiation of erythropoiesis-stimulating agent therapy. In most of the kidney transplant recipients, posttransplant anemia resolved without the use of these agents.

Efficacy and safety of conversion of mycophenolate mofetil to enteric-coated mycophenolate sodium in Mexican renal transplant children

The aim of the study was to evaluate the efficacy and safety of the conversion of MMF to EC-MPS in pediatric renal transplant recipients. We included 12 patients with stable graft function who were receiving MMF treatment. In the first visit, a complete medical examination was performed, which included a GSRS, a nine-point pharmacokinetic profile, samples for renal, liver and hematological tests and evaluation of IMPDH2 gene expression. The patients were transferred to an equimolar dose of EC-MPS. Two wk later, a clinical evaluation and blood collection, as in the first visit were performed. There was no change in serum creatinine, leukocyte count, serum albumin, or transaminase levels, but we found a statistically significant reduction of hemoglobin after conversion (13.2 +/- 1.6 g/dL with MMF vs. 12.5 +/- 1.3 g/dL when receiving EC-MPS). The GSRS total mean score was 16 +/- 12 with MMF vs. 8 +/- 5 with EC-MPA (p < 0.05). There was no statistically significant difference between formulations in the gene expression of IMPDH 2, in the AUC(0-12h) or in C(max). However, peak concentration occurred later with EC-MPS.

Mortality in renal transplant recipients given erythropoietins to increase haemoglobin concentration: cohort study

OBJECTIVE

To determine the optimal range of increase in haemoglobin concentration with treatment with erythropoietins that is safe and is not associated with mortality.

DESIGN

Retrospective cohort study. The analysis was adjusted for several covariables with Cox regression analysis with spline functions. Use of erythropoietins, haemoglobin concentration, and covariables were included in a time varying manner; variable selection was based on the purposeful selection algorithm.

SETTING

Transplantation centres in Austria.

PARTICIPANTS

1794 renal transplant recipients recorded in the Austrian Dialysis and Transplant Registry who received a transplant between 1 January 1992 and 31 December 2004 and survived at least three months.

MAIN OUTCOME MEASURES

Survival time and haemoglobin concentration after treatment with erythropoietins.

RESULTS

The prevalence of use of erythropoietins has increased over the past 15 years to 25%. Unadjusted extended Kaplan-Meier analysis suggests higher mortality in patients treated with erythropoietins, in whom 10 year survival was 57% compared with 78% in those not treated with erythropoietins (P<0.001). In the treated patients there were 5.4 events/100 person years, compared with 2.6 events/100 person years in those not treated (P<0.001). After adjustment for confounding by indication, comorbidities, comedication, and laboratory readings, haemoglobin concentrations >125 g/l were associated with increased mortality in treated patients (hazard ratio 2.8 (95% confidence interval 1.0 to 7.9) for haemoglobin concentration 140 g/l v 125 g/l), but not in those not treated (0.7, 0.4 to 1.5). When haemoglobin concentrations were 147 g/l or above, patients treated with erythropoietins showed significantly higher mortality than those who were not treated (3.0, 1.0 to 9.4).

CONCLUSION

Increasing haemoglobin concentrations to above 125 g/l with erythropoietins in renal transplant recipients is associated with an increase in mortality. This increase was significant at concentrations above 140 g/l.

Impact of very early high doses of recombinant erythropoietin on anemia and allograft function in de novo kidney-transplant patients

After kidney transplantation, occurrence of anemia in the early post-transplant period (<1 month) is high and arises out of issues that are multifactorial. We performed a retrospective single-center study to assess whether delivery of high doses of erythropoietin-stimulating agents (ESA) within the first week of kidney transplantation, translates at 1 month post-transplant, in to causing less anemia and whether it has an impact on allograft function. Ninety-nine patients were not given ESA (group I), whereas 82 were (250 IU/kg/week; group II). All patients had similar pretransplant and baseline (day 0) variables. Similar numbers of group II patients were still receiving ESA by day 14 (97.5%) and day 30 (89%). Respective figures for group I were 27% and 27%. Independent factors for anemia at 1 month post-transplant included: being male subject, treatment for hypertension at pretransplant, anemia at transplant, a higher mean corpuscular volume at transplant, and an induction therapy using antithymocyte globulins. Independent predictive factors for lower creatinine clearance included being female subjects, having a donor aged >50 years, being a recipient aged >50 years, not treated for hypertension at pretransplant, and no post-transplant ESA therapy. High doses of ESA within the first month of kidney transplantation have no impact on anemia or renal function by 1 month post-transplant.

Anemia and erythrocytosis after kidney transplantation: a 5-year graft function and survival analysis

INTRODUCTION

Both anemia and erythrocytosis frequently occur after kidney transplantation. The aim of this study was to analyze the influence of both anemia and erythrocytosis on kidney graft function and long-term patient outcomes following kidney transplantation.

PATIENTS AND METHODS

Three hundred eight-five consecutive patients with at least 12 months of follow-up after successful kidney transplantation were enrolled into this study. Of the total, 88.3% of patients completed a 5-year follow-up. Anemia occurred in 30.4% of patients (with 17.7% showing a hemoglobin concentration (Hb) <11.0 g/dL), whereas erythrocytosis was observed in 19.0% of patients, including 9.6% with hematocrit (HTC) >55%. We also analyzed graft function every 6 months after transplantation for the impact of anemia or erythrocytosis on the 5-year risk of patient death or graft loss.

RESULTS

In 57.3% of anemia patients the Hb did not reach the normal range during the observation time. The mean eGFR-Modification of Diet in Renal Disease (MDRD) at 12 months after transplantation was significantly lower among patients with anemia: 43.9 mL/min/1.73 m(2) (39.5-48.4) vs 55.3 mL/min/1.73 m(2) (53.0-57.6; P < .001). Better 12-month graft function was observed among patients with erythrocytosis, namely, 57.7 mL/min/1.73 m(2) (53.5-62.0). Anemia but not erythrocytosis was associated with an increased risk of graft loss (hazard ratio [HR] = 4.11 [95% confidence interval (CI) 2.02-8.37]; P < .001).

CONCLUSION

Anemia after transplantation was associated with worse kidney graft function and was a strong predictor of graft loss. Erythrocytosis occurs among patients with excellent allograft function; when properly treated it did not increase the risk of graft loss or death.

Does posttransplant anemia at 6 months affect long-term outcome of live-donor kidney transplantation? A single-center experience

BACKGROUND/AIMS

Posttransplantation anemia (PTA) frequently occurs. We aimed to assess the prevalence of anemia at 6 months of transplantation in patients under different protocols of immunosuppression, and to determine the impact of anemia on long-term patient and graft survival.

METHODS

We included 832 renal transplant recipients who were categorized at 6 months according to hemoglobin (Hb) level into two groups: the first group, with Hb >13 g/dl in males and >12 g/dl in females (group I, 385 cases); and the second group, with Hb <13 g/dl in males and <12 g/dl in females (group II, 447 cases). We compared the two groups regarding posttransplant complications as well as patient and graft survival.

RESULTS

Although there was no significant difference between the two groups regarding acute rejection episodes, chronic allograft nephropathy was significantly higher in the anemic group. Other posttransplant medical complications were comparable in both groups. Graft survival was significantly higher in the nonanemic group. However, no difference in patient survival was detected.

CONCLUSION

From this study, we can conclude that prevalence of PTA is high, especially in females and those receiving calcineurine inhibitors (CNI) and mycophenolate mofetil (MMF), and that it was associated with poorer graft outcome but with no effect on patient survival.

Posttransplant anemia: the role of sirolimus

Posttransplant anemia is a common problem that may hinder patients' quality of life. It occurs in 12 to 76% of patients, and is most common in the immediate posttransplant period. A variety of factors have been identified that increase the risk of posttransplant anemia, of which the level of renal function is most important. Sirolimus, a mammalian target of rapamycin inhibitor, has been implicated as playing a special role in posttransplant anemia. This review considers anemia associated with sirolimus, including its presentation, mechanisms, and management.