Improved survival among sickle cell kidney transplant recipients in the recent era

The nephropathy of sickle cell trait and sickle cell disease

Sickle cell syndromes, including sickle cell disease (SCD) and sickle cell trait, are associated with multiple kidney abnormalities. Young patients with SCD have elevated effective renal plasma flow and glomerular filtration rates, which decrease to normal ranges in young adulthood and subnormal levels with advancing age. The pathophysiology of SCD-related nephropathy is multifactorial - oxidative stress, hyperfiltration and glomerular hypertension are all contributing factors. Albuminuria, which is an early clinical manifestation of glomerular damage, is common in individuals with SCD. Kidney function declines more rapidly in individuals with SCD than in those with sickle cell trait or in healthy individuals. Multiple genetic modifiers, including APOL1, HMOX1, HBA1 and HBA2 variants are also implicated in the development and progression of SCD-related nephropathy. Chronic kidney disease and rapid decline in estimated glomerular filtration rate are associated with increased mortality in adults with SCD. Renin-angiotensin-aldosterone system inhibitors are the standard of care treatment for albuminuria in SCD, despite a lack of controlled studies demonstrating their long-term efficacy. Multiple studies of novel therapeutic agents are ongoing, and patients with SCD and kidney failure should be evaluated for kidney transplantation. Given the high prevalence and severe consequences of kidney disease, additional studies are needed to elucidate the pathophysiology, natural history and treatment of SCD-related nephropathy.

Kidney transplantation in sickle cell disease patients: Case series and experience from a Nigerian kidney transplant center

Sickle cell nephropathy is one of the long-term complications of sickle cell disease (SCD). About a quarter of SCD patients who survive up to 40 years of age will require some form of renal replacement therapy in their lifetime. Organ transplantation in SCD patients poses great challenges, particularly in lower middle income countries (LMIC) like Nigeria. This report highlights the management of three SCD patients who successfully underwent renal transplantation. The patients were aged 39, 47, and 58 years, respectively, with similarly previous history of multiple blood transfusions, recurrent vaso-occlusive crises, and had all progressed to end-stage renal disease. Preoperative exchange blood transfusion and plasmapheresis were offered in one and two of the patients, respectively. One of them required preoperative vaccination against encapsulated organisms due to autosplenectomy. Antithymocyte globulin was used as induction therapy in two of these patients while basiliximab was used in the third. All patients are alive with good renal function 18, 24, and 48 months post transplantation, respectively. In conclusion, kidney transplantation can be safely carried out on SCD patients with a satisfactory outcome.

Outcomes of Kidney Transplant Recipients with Sickle Cell Disease: An Analysis of the 2000-2019 UNOS/OPTN Database

Background: Lower patient survival has been observed in sickle cell disease (SCD) patients who go on to receive a kidney transplant. This study aimed to assess the post-transplant outcomes of SCD kidney transplant recipients in the contemporary era. Methods: We used the OPTN/UNOS database to identify first-time kidney transplant recipients from 2010 through 2019. We compared patient and allograft survival between recipients with SCD (n = 105) vs. all other diagnoses (non-SCD, n = 146,325) as the reported cause of end-stage kidney disease. We examined whether post-transplant outcomes improved among SCD in the recent era (2010–2019), compared to the early era (2000–2009). Results: After adjusting for differences in baseline characteristics, SCD was significantly associated with lower patient survival (HR 2.87; 95% CI 1.75–4.68) and death-censored graft survival (HR 1.98; 95% CI 1.30–3.01), compared to non-SCD recipients. The lower patient survival and death-censored graft survival in SCD recipients were consistently observed in comparison to outcomes of recipients with diabetes, glomerular disease, and hypertension as the cause of end-stage kidney disease. There was no significant difference in death censored graft survival (HR 0.99; 95% CI 0.51–1.73, p = 0.98) and patient survival (HR 0.93; 95% CI 0.50–1.74, p = 0.82) of SCD recipients in the recent versus early era. Conclusions: Patient and allograft survival in SCD kidney recipients were worse than recipients with other diagnoses. Overall SCD patient and allograft outcomes in the recent era did not improve from the early era. The findings of our study should not discourage kidney transplantation for ESKD patients with SCD due to a known survival benefit of transplantation compared with remaining on dialysis. Urgent future studies are needed to identify strategies to improve patient and allograft survival in SCD kidney recipients. In addition, it may be reasonable to assign risk adjustment for SCD patients.

Sickle cell nephropathy. Clinical manifestations and new mechanisms involved in kidney injury

Kidney problems are among the most common complications in sickle cell disease (SCD). They occur early in childhood and are one of the main factors related to mortality in these patients. The main underlying pathogenic mechanisms are vaso-occlusion and haemolysis. The renal medulla has ideal conditions for the sickling of red cells due to its low partial pressure of oxygen, high osmolarity and acidic pH. Initially, sickle-cell formation in the vasa recta of the renal medulla causes hyposthenuria. This is universal and appears in early childhood. Microscopic and macroscopic haematuria also occur, in part related to renal papillary necrosis when the infarcts are extensive. Release of prostaglandins in the renal medulla due to ischaemia leads to an increase in the glomerular filtration rate (GFR). Adaptively, sodium reabsorption in the proximal tubule increases, accompanied by increased creatinine secretion. Therefore, the GFR estimated from creatinine may be overestimated. Focal segmental glomerulosclerosis is the most common glomerular disease. Albuminuria is very common and reduction has been found in 72.8% of subjects treated with ACE inhibitors or ARB. Recent evidence suggests that free haemoglobin has harmful effects on podocytes, and may be a mechanism involved in impaired kidney function in these patients. These effects need to be better studied in SCD, as they could provide a therapeutic alternative in sickle cell nephropathy.

Sickle cell nephropathy. Clinical manifestations and new mechanisms involved in kidney injury

Kidney problems are among the most common complications in sickle cell disease (SCD). They occur early in childhood and are one of the main factors related to mortality in these patients. The main underlying pathogenic mechanisms are vaso-occlusion and haemolysis. The renal medulla has ideal conditions for the sickling of red cells due to its low partial pressure of oxygen, high osmolarity and acidic pH. Initially, sickle-cell formation in the vasa recta of the renal medulla causes hyposthenuria. This is universal and appears in early childhood. Microscopic and macroscopic haematuria also occur, in part related to renal papillary necrosis when the infarcts are extensive. Release of prostaglandins in the renal medulla due to ischaemia leads to an increase in the glomerular filtration rate (GFR). Adaptively, sodium reabsorption in the proximal tubule increases, accompanied by increased creatinine secretion. Therefore, the GFR estimated from creatinine may be overestimated. Focal segmental glomerulosclerosis is the most common glomerular disease. Albuminuria is very common and reduction has been found in 72.8% of subjects treated with ACE inhibitors or ARB. Recent evidence suggests that free haemoglobin has harmful effects on podocytes, and may be a mechanism involved in impaired kidney function in these patients. These effects need to be better studied in SCD, as they could provide a therapeutic alternative in sickle cell nephropathy.

Mortality and Access to Kidney Transplantation in Patients with Sickle Cell Disease-Associated Kidney Failure

BACKGROUND AND OBJECTIVES

Patients with sickle cell disease-associated kidney failure have high mortality, which might be lowered by kidney transplantation. However, because they show higher post-transplant mortality compared with patients with other kidney failure etiologies, kidney transplantation remains controversial in this population, potentially limiting their chance of receiving transplantation. We aimed to quantify the decrease in mortality associated with transplantation in this population and determine the chance of receiving transplantation with sickle cell disease as the cause of kidney failure as compared with other etiologies of kidney failure.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a national registry, we studied all adults with kidney failure who began maintenance dialysis or were added to the kidney transplant waiting list in 1998-2017. To quantify the decrease in mortality associated with transplantation, we measured the absolute risk difference and hazard ratio for mortality in matched pairs of transplant recipients versus waitlisted candidates in the sickle cell and control groups. To compare the chance of receiving transplantation, we estimated hazard ratios for receiving transplantation in the sickle cell and control groups, treating death as a competing risk.

RESULTS

Compared with their matched waitlisted candidates, 189 transplant recipients with sickle cell disease and 220,251 control recipients showed significantly lower mortality. The absolute risk difference at 10 years post-transplant was 20.3 (98.75% confidence interval, 0.9 to 39.8) and 19.8 (98.75% confidence interval, 19.2 to 20.4) percentage points in the sickle cell and control groups, respectively. The hazard ratio was also similar in the sickle cell (0.57; 95% confidence interval, 0.36 to 0.91) and control (0.54; 95% confidence interval, 0.53 to 0.55) groups (interaction P=0.8). Nonetheless, the sickle cell group was less likely to receive transplantation than the controls (subdistribution hazard ratio, 0.73; 95% confidence interval, 0.61 to 0.87). Similar disparities were found among waitlisted candidates (subdistribution hazard ratio, 0.62; 95% confidence interval, 0.53 to 0.72).

CONCLUSIONS

Patients with sickle cell disease-associated kidney failure exhibited similar decreases in mortality associated with kidney transplantation as compared with those with other kidney failure etiologies. Nonetheless, the sickle cell population was less likely to receive transplantation, even after waitlist registration.

The Worst Things in Life are Free: The Role of Free Heme in Sickle Cell Disease

Hemolysis is a pathological feature of several diseases of diverse etiology such as hereditary anemias, malaria, and sepsis. A major complication of hemolysis involves the release of large quantities of hemoglobin into the blood circulation and the subsequent generation of harmful metabolites like labile heme. Protective mechanisms like haptoglobin-hemoglobin and hemopexin-heme binding, and heme oxygenase-1 enzymatic degradation of heme limit the toxicity of the hemolysis-related molecules. The capacity of these protective systems is exceeded in hemolytic diseases, resulting in high residual levels of hemolysis products in the circulation, which pose a great oxidative and proinflammatory risk. Sickle cell disease (SCD) features a prominent hemolytic anemia which impacts the phenotypic variability and disease severity. Not only is circulating heme a potent oxidative molecule, but it can act as an erythrocytic danger-associated molecular pattern (eDAMP) molecule which contributes to a proinflammatory state, promoting sickle complications such as vaso-occlusion and acute lung injury. Exposure to extracellular heme in SCD can also augment the expression of placental growth factor (PlGF) and interleukin-6 (IL-6), with important consequences to enthothelin-1 (ET-1) secretion and pulmonary hypertension, and potentially the development of renal and cardiac dysfunction. This review focuses on heme-induced mechanisms that are implicated in disease pathways, mainly in SCD. A special emphasis is given to heme-induced PlGF and IL-6 related mechanisms and their role in SCD disease progression.

Outcomes following kidney transplantation in patients with sickle cell disease: The impact of automated exchange blood transfusion

There are over 12,000 people with sickle cell disease (SCD) in the UK, and 4-12% of patients who develop Sickle Cell Nephropathy (SCN) progress to End Stage Renal Disease (ESRD). Renal transplantation offers the best outcomes for these patients with but their access to transplantation is often limited. Regular automated exchange blood transfusions (EBT) reduce the complications of SCD and may improve outcomes. However, concerns over alloimmunisation limit its widespread implementation. In this retrospective multicenter study, data were collected on 34 SCD patients who received a kidney transplant across 6 London Hospitals between 1997 and 2017. 20/34 patients were on an EBT program, pre or post renal transplantation. Overall patient and graft survival were inferior to contemporaneous UK data in the ESRD population as a whole, a finding which is well-recognised. However, patient survival (CI 95%, p = 0.0032), graft survival and graft function were superior at all time-points in those who received EBT versus those who did not. 4/20 patients (20%) on EBT developed de novo donor specific antibodies (DSAs). 3/14 patients (21%) not on EBT developed de novo DSAs. The incidence of rejection in those on EBT was 5/18 (28%), as compared with 7/13 (54%) not on EBT. In conclusion, our data, while limited by an inevitably small sample size and differences in the date of transplantation, do suggest that long-term automated EBT post renal transplant is effective and safe, with improvement in graft and patient outcomes and no increase in antibody formation or graft rejection.

Liver Transplantation in Patients with Sickle Cell Disease in the United States

BACKGROUND

Up to 30% of patients with sickle cell disease (SCD) develop chronic liver disease via etiologies including sickle cell hepatopathy, acquired viral hepatitis, or secondary hemochromatosis. It is unclear how many patients with SCD ultimately undergo liver transplantation (LT) and what factors are associated with survival after LT. In this study, we examined LT outcomes in these patients by reviewing the Scientific Registry of Transplant Recipients (SRTR) and our institutional experience.

METHODS

Analysis of the SRTR identified 23 LT recipients and five simultaneous liver and kidney transplantation (SLKT) recipients with SCD. Patient demographics and graft and patient survival were analyzed. Two patients with SCD at our institution underwent SLKT.

RESULTS

Review of the SRTR revealed that recipients with SCD had significantly higher model for end-stage liver disease scores (33 versus 21, P = 0.004), preoperative intensive care unit admission (43.5% versus 19.1%, P = 0.007), preoperative dialysis (17.4% versus 4.9%, P = 0.009), and were more likely to be status 1 (26.1% versus 12.1%, P = 0.041) when compared with the reference population of African American LT recipients. Despite being higher risk at the time of LT, patients with SCD had equivalent posttransplant graft and patient survival when compared with the reference population (P = 0.5 and P = 0.2, respectively) and a 2:1 propensity score-matched group (P = 0.5 and P = 0.2, respectively). Two recent SLKT recipients with SCD from our institution have performed well with stable allograft function.

CONCLUSIONS

Data from the SRTR demonstrate that patients with SCD can expect equivalent graft and patient survival after LT despite exhibiting more comorbidities at the time of LT. The low number of patients with SCD who underwent LT in the SRTR in comparison with the rate of chronic liver disease in this population raises the question as to whether a disparity in access to LT exists for this complex population.

American Society of Hematology 2019 guidelines for sickle cell disease: cardiopulmonary and kidney disease

BACKGROUND

Prevention and management of end-organ disease represent major challenges facing providers of children and adults with sickle cell disease (SCD). Uncertainty and variability in the screening, diagnosis, and management of cardiopulmonary and renal complications in SCD lead to varying outcomes for affected individuals.

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians, and other health care professionals in their decisions about screening, diagnosis, and management of cardiopulmonary and renal complications of SCD.

METHODS

ASH formed a multidisciplinary guideline panel that included 2 patient representatives and was balanced to minimize potential bias from conflicts of interest. The Mayo Evidence-Based Practice Research Program supported the guideline development process, including performing systematic evidence reviews up to September 2017. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The panel used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach, including GRADE evidence-to-decision frameworks, to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 10 recommendations for screening, diagnosis, and management of cardiopulmonary and renal complications of SCD. Recommendations related to anticoagulation duration for adults with SCD and venous thromboembolism were also developed.

CONCLUSIONS

Most recommendations were conditional due to a paucity of direct, high-quality evidence for outcomes of interest. Future research was identified, including the need for prospective studies to better understand the natural history of cardiopulmonary and renal disease, their relationship to patient-important outcomes, and optimal management.

Sickle cell disease: a review for the internist

Sickle cell disease (SCD) is the most important hemoglobinopathy worldwide in terms of frequency and social impact, recently recognized as a global public health problem by the World Health Organization. It is a monogenic but multisystem disorder with high morbidity and mortality. Vaso-occlusion, hemolytic anemia and vasculopathy are the hallmarks of SCD pathophysiology. This review focuses both on "time-dependent" acute clinical manifestations of SCD and chronic complications commonly described in adults with SCD. The review covers a broad spectrum of topics concerning current management of SCD targeted at the internists and emergency specialists who are increasingly involved in the care of acute and chronic complications of SCD patients.

Cardiac expression of HMOX1 and PGF in sickle cell mice and haem-treated wild type mice dominates organ expression profiles via Nrf2 (Nfe2l2)

Haemolysis is a major feature of sickle cell disease (SCD) that contributes to organ damage. It is well established that haem, a product of haemolysis, induces expression of the enzyme that degrades it, haem oxygenase-1 (HMOX1). We have also shown that haem induces expression of placental growth factor (PGF), but the organ specificity of these responses has not been well-defined. As expected, we found high level expression of Hmox1 and Pgf transcripts in the reticuloendothelial system organs of transgenic sickle cell mice, but surprisingly strong expression in the heart (P < 0·0001). This pattern was largely replicated in wild type mice by intravenous injection of exogenous haem. In the heart, haem induced unexpectedly strong mRNA responses for Hmox1 (18-fold), Pgf (4-fold), and the haem transporter Slc48a1 (also termed Hrg1; 2·4-fold). This was comparable to the liver, the principal known haem-detoxifying organ. The NFE2L2 (also termed NRF2) transcription factor mediated much of the haem induction of Hmox1 and Hrg1 in all organs, but less so for Pgf. Our results indicate that the heart expresses haem response pathway genes at surprisingly high basal levels and shares with the liver a similar transcriptional response to circulating haem. The role of the heart in haem response should be investigated further.

Kidney biopsy findings in children with sickle cell disease: a Midwest Pediatric Nephrology Consortium study

BACKGROUND

Renal damage is a progressive complication of sickle cell disease (SCD). Microalbuminuria is common in children with SCD, while a smaller number of children have more severe renal manifestations necessitating kidney biopsy. There is limited information on renal biopsy findings in children with SCD and subsequent management and outcome.

METHODS

This is a multicenter retrospective analysis of renal biopsy findings and clinical outcomes in children and adolescents with SCD. We included children and adolescents (age ≤ 20 years) with SCD who had a kidney biopsy performed at a pediatric nephrology unit. The clinical indication for biopsy, biopsy findings, subsequent treatments, and outcomes were analyzed.

RESULTS

Thirty-six SCD patients (ages 4-19 years) were identified from 14 centers with a median follow-up of 2.6 years (0.4-10.4 years). The indications for biopsy were proteinuria (92%) and elevated creatinine (30%). All biopsies had abnormal findings, including mesangial hypercellularity (75%), focal segmental glomerulosclerosis (30%), membranoproliferative glomerulonephritis (16%), and thrombotic microangiopathy (2%). There was increased use of hydroxyurea, angiotensin-converting-enzyme inhibitors, and angiotensin receptor blockers following renal biopsy. At last follow-up, 3 patients were deceased, 2 developed insulin-dependent diabetes mellitus, 6 initiated chronic hemodialysis, 1 received a bone marrow transplant, and 1 received a kidney transplant.

CONCLUSIONS

Renal biopsies, while not commonly performed in children with SCD, were universally abnormal. Outcomes were poor in this cohort of patients despite a variety of post-biopsy interventions. Effective early intervention to prevent chronic kidney disease (CKD) is needed to reduce morbidity and mortality in children with SCD.

Survival and specific outcome of sickle cell disease patients after renal transplantation

The prognosis of sickle cell disease (SCD) patients who need dialysis is poor, but experience with kidney transplantation is limited. This study assessed the characteristics of 36 SCD patients undergoing renal transplantation. Immediate post-surgical complications occurred in 25% of cases. Cytomegalovirus and bacterial infections were frequently observed. Twelve patients died after a median follow-up period of 17·4 months. Overall patient survival was significantly lower in SCD than in the control group without significant difference for overall death-censored graft survival. Our data suggest that renal transplantation should be systematically considered in SCD patients with end-stage renal disease.

Sickle cell disease: Clinical presentation and management of a global health challenge

Sickle cell disease is an autosomal recessive, multisystem disorder, characterised by chronic haemolytic anaemia, painful episodes of vaso-occlusion, progressive organ failure and a reduced life expectancy. Sickle cell disease is the most common monogenetic disease, with millions affected worldwide. In well-resourced countries, comprehensive care programs have increased life expectancy of sickle cell disease patients, with almost all infants surviving into adulthood. Therapeutic options for sickle cell disease patients are however, still scarce. Predictors of sickle cell disease severity and a better understanding of pathophysiology and (epi)genetic modifiers are warranted and could lead to more precise management and treatment. This review provides an extensive summary of the pathophysiology and management of sickle cell disease and encompasses the characteristics, complications and current and future treatment options of the disease.

Toward dual hematopoietic stem-cell transplantation and solid-organ transplantation for sickle-cell disease

Sickle-cell disease (SCD) leads to recurrent vaso-occlusive crises, chronic end-organ damage, and resultant physical, psychological, and social disabilities. Although hematopoietic stem-cell transplantation (HSCT) is potentially curative for SCD, this procedure is associated with well-recognized morbidity and mortality and thus is ideally offered only to patients at high risk of significant complications. However, it is difficult to identify patients at high risk before significant complications have occurred, and once patients experience significant organ damage, they are considered poor candidates for HSCT. In turn, patients who have experienced long-term organ toxicity from SCD such as renal or liver failure may be candidates for solid-organ transplantation (SOT); however, the transplanted organs are at risk of damage by the original disease. Thus, dual HSCT and organ transplantation could simultaneously replace the failing organ and eliminate the underlying disease process. Advances in HSCT conditioning such as reduced-intensity regimens and alternative donor selection may expand both the feasibility of and potential donor pool for transplantation. This review summarizes the current state of HSCT and organ transplantation in SCD and discusses future directions and the clinical feasibility of dual HSCT/SOT.

How I treat the older adult with sickle cell disease

With increasing survival, cumulative complications of sickle cell disease (SCD), which develop insidiously over time, are becoming more apparent and common in older patients, particularly those in their fifth decade and beyond. The older patient is also more likely to develop other age-related nonsickle conditions that interact and add to the disease morbidity. A common misconception is that any symptom in a SCD patient is attributable to their SCD and this may lead to delays in diagnosis and appropriate intervention. We recommend regular comprehensive reviews and monitoring for early signs of organ damage and a low threshold for the use of hydroxyurea and blood transfusions as preventative measures for end-organ disease. Treatable comorbidities and acute deterioration should be managed aggressively. Although the primary goal in management of the older adult with SCD is improving anemia and minimizing organ damage, the time has come for us to be more proactive in considering curative therapies previously offered to the younger patient. Curative or experimental interventions should be discussed early, before complications render the patients ineligible for these treatments.

Sickle cell disease

Sickle cell disease (SCD) is a group of inherited disorders caused by mutations in HBB, which encodes haemoglobin subunit β. The incidence is estimated to be between 300,000 and 400,000 neonates globally each year, the majority in sub-Saharan Africa. Haemoglobin molecules that include mutant sickle β-globin subunits can polymerize; erythrocytes that contain mostly haemoglobin polymers assume a sickled form and are prone to haemolysis. Other pathophysiological mechanisms that contribute to the SCD phenotype are vaso-occlusion and activation of the immune system. SCD is characterized by a remarkable phenotypic complexity. Common acute complications are acute pain events, acute chest syndrome and stroke; chronic complications (including chronic kidney disease) can damage all organs. Hydroxycarbamide, blood transfusions and haematopoietic stem cell transplantation can reduce the severity of the disease. Early diagnosis is crucial to improve survival, and universal newborn screening programmes have been implemented in some countries but are challenging in low-income, high-burden settings.

Chronic organ failure in adult sickle cell disease

Sickle cell disease is now a chronic adult illness characterized by progressive multiorgan failure, particularly involving the brain and kidney. The etiology is multifactorial; it includes hemolysis and nitric oxide deficiency. As patients age, most experience neurologic insult. Twenty-five percent of older adults have had a clinical stroke and at least half of the population have had a silent infarct, cortical atrophy, and neurocognitive impairment. Periodic screening with neuroimaging and neurocognitive testing is recommended. Identification and correction of modifiable risk factors such as nocturnal hypoxemia, obstructive sleep apnea, and physical exercise programs should be implemented. Patients with neurocognitive impairment require cognitive remediation and educational accommodations. Chronic renal disease occurs in 25% of older adults and results in 50% of their deaths. Renal failure often develops insidiously. It can be prevented or minimized by early screening and treatment of modifiable risk factors including hypertension and microalbuminuria. There is an increasing number of therapeutic options, including inhibitors of the renin angiotensin system, angiotensin-II receptor blockers, endothelin-1 receptor antagonist, and haptoglobin therapy. Patients with sickle cell disease have increased mortality rates from renal failure compared with nonsickle cell patients, in part from a lack of access to early multidisciplinary care, including timely initiation of dialysis and renal transplantation.

Health Disparities in Kidney Transplantation for African Americans

BACKGROUND

The persistent challenges of bridging healthcare disparities for African Americans (AAs) in need of kidney transplantation continue to be unresolved at the national level. This healthcare disparity is multifactorial: stemming from limited kidney donors suitable for AAs; inconsistent care coordination and suboptimal risk factor control; social determinants, low socioeconomic status, reduced access to care; and mistrust of clinicians and the healthcare system.

SUMMARY

There are numerous opportunities to significantly lessen the disparities in kidney transplantation for AAs through the following measures: the adoption of new care and patient engagement models that include education, enhanced practice-level cultural sensitivity, and timely referral as well as increased research on the impact of the environment on genetic risk, and implementation of new transplantation-related policies. Key Messages: This systematic review describes pretransplant concerns related to access to kidney transplantation, posttransplant complications, and policy interventions to address the challenging issues associated with kidney transplantation in AAs.

Morbidity and mortality of sickle cell disease patients starting intermittent haemodialysis: a comparative cohort study with non- Sickle dialysis patients

We performed a retrospective study to assess the changes in clinical, biological and heart echocardiographic parameters in 32 sickle cell disease (SCD) patients beginning haemodialysis. Acute SCD-related complications were similar at 6 months before and 6 months after the initiation of haemodialysis. Median haemoglobin level did not change significantly, but the need for blood transfusions increased (P < 0·001). The 5-year incidence of death was higher in SCD patients (P < 0·0001). The 5-year likelihood of receiving a renal graft was lower in SCD patients (P = 0·022). Our findings suggest that SCD patients have poorer survival and a lower likelihood of receiving a renal graft.

The five key things you need to know to manage adult patients with sickle cell disease

The lack of a strong evidence base to guide the management of adults with sickle cell disease (SCD) makes it difficult for patients to receive high quality care outside of specialty centers. As there is a dearth of providers with sickle cell expertise, the purpose of this article is to identify some of the key things every provider who manages the care of adults with SCD should know. Managing adults with SCD requires excellent clinical skills, as it can affect every organ and cause life-threatening complications but it also requires a willingness to manage patients who often have psychosocial issues that are complex and impact care and care delivery in very significant ways. We have chosen topics for which there is a limited evidence base but which have significant clinical consequences if left unrecognized or poorly managed. The topics that will be addressed include chronic pain, neurocognitive dysfunction, renal disease, venous thromboembolism, and avoiding the inappropriate use of red cell transfusions.

[Chronic renal failure in sickle cell disease: A retrospective analysis of 100 adults sickle cell patients from black Africa]

The prevalence of chronic renal failure (CRF) in sickle cell disease (SCD) patients could vary from one country to another depending on the modalities of management. The aim of the present study was to appreciate the epidemiology of CRF in SCD patients from black Africa in order to search for promoting factors. One hundred SCD adult patients have been considered for the study. The glomerular filtration rate (GFR) has been estimated according to the CKD-EPI formula. Three groups of patients have been identified according to the value of their GFR. The mean age of the patients was 30.84±8.26 years. Male gender has represented 51% of the study population. The mean GFR value was 175.4±86.2 mL/min/1.73 m(2). The prevalence of CRF was 11%. About 3% of them had severe CRF. Subjects with normal GFR were 20%. Subjects with glomerular hyperfiltration (HF) were 69%. By univariate analysis, when subjects with HF were compared with those presenting normal GFR, the following factors have appeared to be significantly associated: female gender (female 60.9% versus male 39.1%; P<0.01), weight <60 kg (weight <60 kg; 53.67±9.45 kg versus weight >60 kg; 59.9±9.41 kg; P<0.008), age <30 years (younger age 29.36±7.9 years versus older age 35.14±8.02 years; P<0.001), lower hemoglobin value (9.38±2,3 g/dL versus 10.33±2.61 g/dL; P<0.04). By logistic regression analysis, age <30 years (age >30 years; OR=0.12 [CI95% 0.03-04]; P<0.001), female gender (male gender; OR=0.17 [0.04-0.64]; P<0.01), weight <60 kg (weight >60 kg; OR=0.19 [CI95% 0.05-0.72]; P<0.01) were associated with HF. By univariate analysis, when subjects with CRF were compared with those presenting normal GFR, a lower hemoglobin value was significantly associated with CRF (7.92±2.7 g/dL versus 10.43±2.5 g/dL; P<0.009). There was a trend for subjects not being under maintenance therapy to more experience CRF (36.4% versus 70%; P<0.07). By logistic regression analysis, only a low hemoglobin value was associated to CRF (higher hemoglobin level; OR=0.55 [0.20-6.3]; P<0.01). In total, CRF and HF are frequent complications in SCD adult patients from black Africa.

Management of the Dialysis Patient with Sickle Cell Disease

While patients with sickle cell disease currently constitute a very small minority of the US dialysis population (0.1%), there is anticipated growth of this group as the life expectancy of those with sickle cell disease (SCD) increases. SCD patients suffer a high burden of morbidity, which is enhanced by the presence of end-stage renal disease (ESRD). In this review, we discuss the pathophysiology of SCD and the basic tenets of its management with focus on the dialysis patient with SCD. Anemia in dialysis patients with SCD is a unique challenge. The hemoglobin target in SCD dialysis patients with ESRD should not exceed 10 g/dl. SCD patients, and particularly those on dialysis, are likely to be poorly responsive to erythropoietin-stimulating agent (ESA) therapy and might be at increased risk for vaso-occlusive crisis (VOC) with ESA. Iron chelation and hydroyxurea therapy require special considerations and modifications in dialysis patients with SCD. There are theoretical advantages to both hemodialysis (HD) and peritoneal dialysis (PD) in SCD patients. With HD, there is a secure vascular access available for both standard and exchange blood transfusion in patients who need them. With PD, the absence of an acute rise in hematocrit with ultrafiltration (UF) might offer lower risk of VOC. During VOC, reduction in UF goals should be considered but administration of intravenous fluids should be reserved only for clear cases of volume depletion. Finally, renal transplantation appears to confer a survival advantage to dialysis in SCD patients and should be pursued when possible.

The glomerulopathy of sickle cell disease

Sickle cell disease (SCD) produces many structural and functional abnormalities in the kidney, including glomerular abnormalities. Albuminuria is the most common manifestation of glomerular damage, with a prevalence between 26 and 68% in adult patients. The pathophysiology of albuminuria in SCD is likely multifactorial, with contributions from hyperfiltration, glomerular hypertension, ischemia-reperfusion injury, oxidative stress, decreased nitric oxide (NO) bioavailability, and endothelial dysfunction. Although its natural history in SCD remains inadequately defined, albuminuria is associated with increased echocardiography-derived tricuspid regurgitant jet velocity, systemic blood pressure, and hypertension, as well as history of stroke, suggesting a shared vasculopathic pathophysiology. While most patients with albuminuria are treated with angiotensin converting enzyme inhibitors/angiotensin receptor blockers, there are no published long-term data on the efficacy of these agents. With the improved patient survival following kidney transplantation, SCD patients with end-stage renal disease should be considered for this treatment modality. Given the high prevalence of albuminuria and its association with multiple SCD-related clinical complications, additional studies are needed to answer several clinically important questions in a bid to adequately elucidate its pathophysiology, natural history, and treatment.

[Spectrum of renal manifestations in sickle cell disease]

Sickle cell disease (SCD), the most common hemoglobinopathy, is an increasing cause of chronic kidney disease. In the last decade, we have witnessed a better understanding in the characterization of clinical manifestations and pathogenesis of sickle cell nephropathy. The spectrum of renal diseases during SCD includes various renal manifestations such as impairment of urinary concentrating ability, defect in urine acidification, renal papillary necrosis and proteinuria related to glomerular injury leading to progressive end-stage renal disease. Endothelial dysfunction related to chronic hemolysis and the relative renal hypoxia caused by vaso-occlusive sickle red blood cells are probably two key factors for SCN development. Optimal therapeutic management (including the use of blockers of the renin-angiotensin system) of patients with proteinuria remains to be determined. Renal replacement therapy with dialysis is required in SCD patients with end-stage renal disease but these patients should probably undergo kidney transplantation that requires careful management.