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

Risk factors and current state of therapy for anemia after kidney transplantation

Post-transplant anemia is one of the most common complications in kidney transplant recipients, severely affecting patient prognosis and quality of life, and is an independent predictor of graft kidney loss and patient mortality. However, our clinical understanding and the attention given to post-transplant anemia are currently insufficient. This paper reviews the current status, risk factors, and therapeutic progress in anemia after transplantation in kidney transplant recipients. We recommend that clinical staff pay attention to anemia and its complications in kidney transplant recipients and intervene early for anemia.

Blood transfusions post kidney transplantation are associated with inferior allograft and patient survival-it is time for rigorous patient blood management

Background

Patient Blood Management (PBM), endorsed by the World Health Organisation is an evidence-based, multi-disciplinary approach to minimise inappropriate blood product transfusions. Kidney transplantation presents a particular challenge to PBM, as comprehensive evidence of the risk of transfusion is lacking. The aim of this study is to investigate the prevalence of post-transplant blood transfusions across multiple centres, to analyse risk factors for transfusion and to compare transplant outcomes by transfusion status.

Methods

This analysis was co-ordinated via the UK Transplant Registry within NHS Blood and Transplant (NHSBT), and was performed across 4 centres. Patients who had received a kidney transplant over a 1-year period, had their transfusion status identified and linked to data held within the national registry.

Results

Of 720 patients, 221(30.7%) were transfused, with 214(29.7%) receiving a red blood cell (RBC) transfusion. The proportion of patients transfused at each centre ranged from 20% to 35%, with a median time to transfusion of 4 (IQR:0-12) days post-transplant. On multivariate analysis, age [OR: 1.02(1.01-1.03), p=0.001], gender [OR: 2.11(1.50-2.98), p<0.0001], ethnicity [OR: 1.28(1.28-2.60), p=0.0008], and dialysis dependence pre-transplant [OR: 1.67(1.08-2.68), p=0.02], were associated with transfusion. A risk-adjusted Cox proportional hazards model showed transfusion was associated with inferior 1-year patient survival [HR 7.94(2.08-30.27), p=0.002] and allograft survival [HR: 3.33(1.65-6.71), p=0.0008], and inferior allograft function.

Conclusion

RBC transfusions are common and are independently associated with inferior transplant outcomes. We urge that further research is needed to understand the mechanisms behind the outcomes, to support the urgent development of transplant-specific anaemia guidelines.

Histopathological Features of Time-Zero Kidney Biopsy Are Predictive Factors for Posttransplant Anemia

INTRODUCTION

Posttransplant anemia (PTA) is a common complication of kidney transplantation, associated with reduced graft survival and higher mortality. We aimed to determine the association of PTA with histopathological characteristics of time-zero allograft biopsy and donor clinical characteristics.

METHODS

We conducted a retrospective, observational cohort study that included 587 patients who underwent kidney transplantation in our center. Hemoglobin levels were assessed at 6 and 12 months after transplantation, and anemia was defined according to World Health Organization criteria. The kidney allograft time-zero biopsy has been done in all investigated cases. The evaluated histopathological parameters of the kidney allografts included glomerulosclerosis, arteriolar hyalinosis (AH), vascular fibrous intimal thickening (CV), interstitial fibrosis, tubular atrophy, and interstitial fibrosis and tubular atrophy. The Banff Classification of Allograft Pathology criteria were followed to assess the allograft histopathological changes.

RESULTS

The prevalence of anemia was 31.3% at 6 months after transplantation and 23.5% at 12 months. There was an association between 20-50% glomerulosclerosis and PTA in both time points, independently from estimated glomerular filtration rate. AH and interstitial fibrosis were identified as independent risk factors for anemia 6 months after transplantation.

CONCLUSION

Histopathological features of time-zero kidney biopsy may be predictors of PTA. Among them, our study recognized 20-50% degree of glomerulosclerosis, AH, and CV as the most significant risk factors for PTA.

Beneficial effect of roxadustat on early posttransplant anemia and iron utilization in kidney transplant recipients: a retrospective comparative cohort study

Background

Although posttransplant anemia (PTA) is a common complication after kidney transplant, it has not been thoroughly evaluated for appropriate treatment. Roxadustat can stimulate erythropoiesis by increasing erythropoietin (EPO) production and improving the utilization of iron. However, there are currently a few case reports describing its effect on PTA in kidney transplant recipients (KTRs). Our purpose was to evaluate the efficacy and safety of roxadustat in KTRs with PTA.

Methods

In this retrospective study, KTRs with early PTA were divided into a roxadustat group, erythropoiesis-stimulating agent (ESA) group, and untreated group (neither roxadustat nor ESA) according to the treatment prescribed by their physicians. We compared the levels of hemoglobin (Hb), creatinine, lipids, hepcidin, intact fibroblast growth factor 23 (iFGF23) and iron-related indices, at baseline and different time points posttransplant. Outcome was assessed at both month 3 and month 12 posttransplant. Adverse events during the treatment course were also recorded.

Results

A total of 57 KTRs were included (n=22 roxadustat group, n=13 ESA group, n=22 untreated group). There was no difference in age, sex, body mass index, dialysis method and duration, donor type among three groups at baseline. The mean Hb levels at month 3 posttransplant (128.00±19.62 vs. 118.59±11.60 g/L, P=0.048) and the average change in Hb levels from week 2 to month 3 (48.05±22.53 vs. 31.45±12.96 g/L, P=0.005) in the roxadustat group were significantly higher than those in the untreated group. However, there was no significant difference in the above indices between the roxadustat and ESA groups. At month 3, the total iron binding capacity (TIBC) and levels of transferrin were significantly higher while levels of ferritin, hepcidin and iFGF23 were significantly lower in the roxadustat group than in other groups (P<0.05). No significant difference was found in creatinine or estimated glomerular filtration rate (eGFR) levels among the three groups at month 3. During the follow-up, no adverse events related to roxadustat were reported.

Conclusions

Administration of roxadustat in KTRs with early PTA could elevate Hb levels effectively and safely by enhancing endogenous EPO production and improving iron utilization. Further randomized studies with larger sample size are necessary to verify our results.

Nutrition Disturbances and Metabolic Complications in Kidney Transplant Recipients: Etiology, Methods of Assessment and Prevention-A Review

Nutrition disturbances occur at all stages of chronic kidney disease and progress with the decrease of the kidney filtration rate. Kidney transplantation (KTx) as the best form of kidney replacement therapy poses various nutritional challenges. Prior to transplantation, recipients often present with mild to advanced nutrition disturbances. A functioning allograft not only relieves uremia, acidosis, and electrolyte disturbances, but also resumes other kidney functions such as erythropoietin production and vitamin D3 metabolism. KTx recipients represent a whole spectrum of undernutrition and obesity. Since following transplantation, patients are relieved of most dietary restrictions and appetite disturbances; they resume old nutrition habits that result in weight gain. The immunosuppressive regimen often predisposes them to dyslipidemia, glucose intolerance, and hypertension. Moreover, most recipients present with chronic kidney graft disease at long-term follow-ups, usually in stages G2-G3T. Therefore, the nutritional status of KTx patients requires careful monitoring. Appropriate dietary and lifestyle habits prevent nutrition disturbances and may improve kidney graft function. Despite many nutritional guidelines and recommendations targeted at chronic kidney disease, there are few targeted at KTx recipients. We aimed to provide a brief review of nutrition disturbances and known nutritional recommendations for kidney transplant recipients based on the current literature and dietary trends.

Tertiary and Postrenal Transplantation Hyperparathyroidism

Patients who have undergone kidney transplantation (KTx) (KTxps) are a distinctive population characterized by the persistence of some metabolic anomalies present during end-stage renal disease. Mineral metabolism (MM) parameters are frequently altered after KTx. These alterations involve calcium, phosphorus, vitamin D, and parathormone (PTH) disarrangements. At present, there is little consensus about the correct monitoring and management of PTH disorders in KTxps. This article presents the prevalence and epidemiologic and clinical impact of post-KTx hyper-PTH. The principal biochemical and instrumental investigations and the therapeutic options for these conditions are also reported.

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.

Role of Prior Split Renal Function for Living Kidney Transplantation in Recipients and Donors

PURPOSE

The purpose of this study was to determine the relationship between pre-operative donor split renal function (SRF) and the renal function outcome of donors and recipients after kidney transplantation (KT).

METHODS

A total of 217 living KT cases were investigated. The estimated glomerular filtration rate (eGFR) change of recipients and donors, as well as graft survival, were analyzed based on the donor SRF. The difference in SRF (dSRF) in a donor was defined as follows: the SRF of the donated kidney minus the SRF of the remaining kidney determined by pre-operative ^99mTc-diethylenetriaminepentaacetic acid in the donors. The dSRF was categorized into tertiles.

RESULTS

The dSRF was not associated with the eGFR in recipients in any tertile at 6 or 12 months post-KT. The overall graft and patient survival did not differ significantly among tertiles. Donors in the high tertile, who donated kidneys with a higher SRF, showed a greater reduction in eGFR than did donors in the low and middle tertile after adjustment for function of the not-donated kidney (-34 ± 1.9 vs -28 ± 2.2, and -27 ± 1.3 mL/min/1.73 m², P < .05).

CONCLUSIONS

The dSRF did not affect the post-KT renal function or graft survival in recipients. However, the donors who donated the better functioning kidney had a poorer renal function after donation.

Change in the Pattern of Posttransplantation Anemia in Kidney Receptors: Sex Role in Recipients and Type of Donor

OBJECTIVE

Posttransplant anemia (PTA) in kidney recipients is a complication that has repercussions mainly of cardiovascular consequence. The objective of this study is to determine the prevalence of anemia, as well as the relationship between kidney recipient and donor sex, in the presence or absence of anemia at 12 months after kidney transplant (KT).

MATERIAL AND METHODS

Observational, longitudinal study of KTs made over a 5-year period, from 2013 to 2017, in a renal transplant unit from La Raza National Health Care Medical Center. Three hundred twenty-eight records were analyzed. Hemoglobin (Hb) and the presence or absence of anemia according to the definition by the World Health Organization were analyzed. The association between kidney recipient sex and donor type (living or deceased) was evaluated. Analysis of central tendency and dispersion were performed and the mean difference was established with χ² test or Student t test. Significance level was set at P < .05.

RESULTS

The mean Hb (standard deviation) before KT was 10.38 (2.16) g/dL; Hb at 12 months was 14.47 (2.37) g/dL with an absolute increase of 4.09 g/dL. Before KT, male kidney recipients had a mean Hb of 10.54 (2.17) g/dL. At 12 months post-KT, mean Hb was 15.33 (2.25) with a change of 4.79 g/dL. Before KT, female kidney recipients had a mean Hb of 10.16 (2.13) g/dL. At 12 months post-KT, mean Hb was 13.31 (2.01) with a change of 3.15 g/dL. The difference between both sexes was 1.64 g/dL at the end of 12 months. Sixteen out of 152 (10.5%) patients had a serum creatinine (Cr) < 1.2 mg/dL and anemia; 36 out of 176 (20.5%) patients had a Cr ≥ 1.2 mg/dL and anemia (P = .014). In the bivariate logistic regression with an odds ratio of 2.047 (95% confidence interval, 1027-4078; P = .042) for higher Cr levels and the presence of persistent anemia.

CONCLUSIONS

There is a prevalence of anemia in female kidney recipients and recipients of kidneys from deceased donors. There is a higher risk of persistent anemia in the case of patients with some degree of graft failure at 12 months.

Chronic Use of Proton-Pump Inhibitors and Iron Status in Renal Transplant Recipients

Proton-pump inhibitor (PPI) use may influence intestinal iron absorption. Low iron status and iron deficiency (ID) are frequent medical problems in renal transplant recipients (RTR). We hypothesized that chronic PPI use is associated with lower iron status and ID in RTR. Serum iron, ferritin, transferrin saturation (TSAT), and hemoglobin were measured in 646 stable outpatient RTR with a functioning allograft for ≥ 1 year from the "TransplantLines Food and Nutrition Biobank and Cohort Study" (NCT02811835). Median time since transplantation was 5.3 (1.8-12.0) years, mean age was 53 ± 13 years, and 56.2% used PPI. In multivariable linear regression analyses, PPI use was inversely associated with serum iron (β = -1.61, p = 0.001), natural log transformed serum ferritin (β = -0.31, p < 0.001), TSAT (β = -2.85, p = 0.001), and hemoglobin levels (β = -0.35, p = 0.007), independent of potential confounders. Moreover, PPI use was independently associated with increased risk of ID (Odds Ratio (OR): 1.57; 95% Confidence Interval (CI )1.07-2.31, p = 0.02). Additionally, the odds ratio in RTR taking a high PPI dose as compared to RTR taking no PPIs (OR 2.30; 95% CI 1.46-3.62, p < 0.001) was higher than in RTR taking a low PPI dose (OR:1.78; 95% CI 1.21-2.62, p= 0.004). We demonstrated that PPI use is associated with lower iron status and ID, suggesting impaired intestinal absorption of iron. Moreover, we found a stronger association with ID in RTR taking high PPI dosages. Use of PPIs should, therefore, be considered as a modifiable cause of ID in RTR.