An Underappreciated Problem in Renal Transplant Recipients: Anemia

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.

Haematological disorders following kidney transplantation

Transplantation offers cure for some haematological cancers, end-stage organ failure, but at the cost of long-term complications. Renal transplantation is the best-known kidney replacement therapy and it can prolong end-stage renal disease patient lives for decades. However, patients after renal transplantation are at a higher risk of developing different complications connected not only with surgical procedure but also with immunosuppressive treatment, chronic kidney disease progression and rejection processes. Various blood disorders can develop in post-transplant patients ranging from relatively benign anaemia through cytopenias to therapy-related myelodysplasia and acute myeloid leukaemia (AML) and post-transplant lymphoproliferative disorders followed by a rare and fatal condition of thrombotic microangiopathy and haemophagocytic syndrome. So far literature mainly focused on the post-transplant lymphoproliferative disease. In this review, a variety of haematological problems after transplantation ranging from rare disorders such as myelodysplasia and AML to relatively common conditions such as anaemia and iron deficiency are presented with up-to-date diagnosis and management.

Similar Anemic Control Between Chronic Kidney Diseases in Patients With and Without Transplantation on Entry to Dialysis

BACKGROUND

Transplant recipients are supposedly in a more anemic, catabolic, and even inflammatory state at re-entering hemodialysis due to chronic rejection. The goal of this study was to clarify how transplant recipients can re-enter dialysis safely by focusing on control of anemia.

METHODS

From 2012 to 2014, a total of 29 transplant recipients re-entered hemodialysis because of chronic rejection (ie, the chronic kidney disease with transplant [CKDT] group). At the same time, in 2014, a total of 30 patients with chronic kidney disease without transplantation entered dialysis as the control group (ie, the CKD group). CKDT recipients (mean ± standard deviation age, 41.9 ± 11.8 years; 18 male subjects, 10 female subjects; frequency of diabetes, 10%; duration of graft survival, 12.5 ± 4.3 years) were younger and fewer had diabetes compared with the CKD group (age, 53.2 ± 10.5 years; 21 male subjects, 9 female subjects; frequency of diabetes, 36%). Patient characteristics at entering dialysis in both groups were analyzed according to retrospective chart review.

RESULTS

At entering dialysis, there were no significant differences between the CKD and CKDT groups in terms of the following: dose of darbepoetin; concentrations of hemoglobin, albumin, and C-reactive protein; cardiothoracic ratio; blood urea nitrogen and creatinine levels; estimated glomerular filtration rate; initial ultrafiltration; and duration of hospitalization for initiation of dialysis. The only difference between groups was mean weight at entry to dialysis (CKDT group, 58.5 ± 15.1 kg; CKD group, 67.1 ± 14.8 kg; P = .03). The darbepoetin dose per kilogram of weight did not differ between groups (CKDT, 2.28 ± 2.03 μg/kg; CKD, 2.12 ± 1.6 μg/kg; P = .95) in the final month before entry to dialysis.

CONCLUSIONS

Safe re-initiation of dialysis is important for recipient survival. Although anemia is supposedly higher in transplant recipients due to immunosuppression, this single-center analysis found no difference in anemia in CKD with or without transplantation, caused by good use of erythropoietin-stimulating agents in both groups.

Anemia in living donor kidney transplantation

BACKGROUND

We evaluated the prevalence of pretransplantation and posttransplantation anemia and its effect on serum creatinine levels among living donor kidney transplant recipients.

METHODS

We reviewed retrospectively 170 adult patients who underwent living donor kidney transplantation between 1994 and 2009. We defined anemia as hemoglobin (Hb) ≤12 g/dL for women and ≤13 g/dL for men with severe anemia as Hb <11 g/dL for both men and women (World Health Organization criteria). Patients were also categorized according to Hb levels less than or greater than 10 g/dL for correlation with recipient serum creatinine levels at months 1, 3, 6, and 12.

RESULTS

Mean recipient and donor ages were 33 ± 10 and 45 ± 12 years, respectively. Mean cold ischemia time was 76 ± 43 minutes. At the time of transplantation, anemia and severe anemia prevalences were 86.7% and 58.8%, respectively. Anemia was observed in 64 patients (42.1%) at posttransplantation month 3. Pretransplantation severe anemia was a good predictor of both Hb levels and anemia presence posttransplantation. Pretransplantation anemia and severe anemia caused greater requirements for posttransplantation blood transfusions (P < .05). Younger age and female gender were significant risk factors for severe anemia pretransplantation. There was a significant correlation between posttransplantation Hb levels and serum creatinine levels at 12 month (P = .01). Recipient female gender and longer hospital stay were significant risk factors for both anemia and severe anemia posttransplantation. Higher recipient weight and history of acute rejection episode were also significant for posttransplantation severe anemia.

CONCLUSION

This study indicated that successful kidney transplantation had a positive effect on Hb levels. Posttransplantation anemia predicted worse graft function in the first month after transplantation.

Microalbuminuria is associated with high prevalence of anemia in renal transplant recipients

BACKGROUND AND AIM

Prevalence of anemia is higher in diabetic patients with microalbuminuria than those with normoalbuminuria despite the absence of significant renal impairment. The aim of this study was to investigate whether there was a relationship between microalbuminuria and anemia in renal transplant recipients (RTRs).

PATIENTS AND METHOD

Twenty-eight RTRs with microalbuminuria and 21 control RTRs with normoalbuminuria were classified based on urinary albumin creatinine ratios (UACR) of 0.03-0.3 versus <0.03, respectively. Anemia was defined as a hemoglobin level <13 g/dL for men and <12 g/dL for women.

RESULTS

Anemia was observed in 13 (46.4%) microalbuminuric and 4 (19%) normoalbuminuric patients (P = 0.044). Hemoglobin level was significantly lower in the microalbuminuric than the normoalbuminuric group (13.3 ± 1.3 g/dL vs 14.4 ± 1.9 g/dL, respectively; P = .018). Although creatinine clearance was significantly higher among the normoalbuminuric group (84 ± 30 mL/min vs 65 ± 22 mL/min, respectively; P = .017), mean creatinine clearance in microalbuminuric group was >60 mL/min, the threshold value for anemia due to erythropoietin (EPO) deficiency. In contrast, there was no significant difference between the 2 groups for age, gender, donor source, and transplant duration.

CONCLUSION

Anemia was frequent among RTRs displaying microalbuminuria, which may reflect EPO deficiency due to the tubulointerstitial injury of chronic allograft nephropathy. The EPO deficiency may begin before significant deterioration in excretory function of the kidney.

Post-transplant anemia and associated risk factors: the impact of steroid-free therapy

CONTEXT AND OBJECTIVE

The prevalence of post-renal transplant anemia (PTA) reported in the literature is variable and several factors contribute towards its pathophysiology. This study aimed to investigate the prevalence of PTA, its associated risk factors and the impact of therapy without steroids.

DESIGN AND SETTING

Retrospective cohort study in a renal transplantation unit at a tertiary hospital.

METHODS

Anemia was defined as hemoglobin (Hb) < 12 g/dl in female adult recipients and < 13 g/dl in males. Donor and recipient age and gender, type of donor, creatinine, delayed graft function, acute rejection, use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB) and therapy without steroids were investigated as risk factors for PTA through multivariate logistical regression analysis.

RESULTS

Evaluations were performed on 258 recipients (mean age: 38.8 years; 60.5% males; 35.7% did not receive steroids). Anemia was diagnosed in 38% of the patients (at the sixth month, M6), 28% (M12), 32% (M24) and 45% (at last follow up). Donor age > 50 years was associated with greater risks of PTA at M6 (odds ratio (OR) = 4.68) and M24 (OR = 6.57), as well as with therapy without steroids at M6 (OR = 2.96). Delayed graft function was independently associated with PTA at M6 (OR = 3.66) and M12 (OR = 2.85).

CONCLUSION

The lowest prevalence of PTA was observed between M9 and M24 after renal transplantation. Delayed graft function, donor age and therapy without steroids were the most important factors associated with PTA.

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.

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.

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.

Hematologic abnormalities following renal transplantation

Recipients of renal allografts are surviving longer and, consequently, may experience a variety of complications related not only to the transplanted kidney, but also to the hematopoietic system. Common hematologic complications in the renal transplant patient include abnormalities of one cell line, such as post-transplantation erythrocytosis or anemia, that are often treatable with simple measures. Conversely, pathologies involving the leukocyte and platelet population often exist in the context of pancytopenia, which may be a manifestation of systemic infection (e.g., cytomegalovirus, human herpesvirus 8) or malignancy (post-transplantation lymphoproliferative disorders). Uncommon, but life-threatening, processes complicating renal transplantation include hepatosplenic gammadelta T-cell lymphoma and viral-induced hemophagocytic syndrome, both of which are associated with severe pancytopenia and, often, death. Since this patient population is often managed in a multidisciplinary fashion by nephrologists, infection specialists, transplant surgeons, hematologists, and internal medicine physicians, a succinct review of this topic is warranted.