Acute kidney injury in critically ill allo-HSCT recipients

Leveraging Electronic Health Records to Predict the Risk of Acute Kidney Injury after Allogeneic Hematopoietic Cell Transplantation

BACKGROUND

The objective of this study is to assess the electronic health records (EHRs), which are potential risk factors for acute kidney injury (AKI) after allogenic hematopoietic cell transplantation (allo-HCT), and to propose a basic dataset and score for the calculation of HCT-acute kidney injury risk (HCT-AKIR).

METHODS

We undertook a retrospective analysis of the EHRs of 312 patients. Pre- and post-transplant factors were assessed, recognizing the following structured entries: laboratory data, encounters, medication, imaging studies, diagnoses, and procedures. Composite variables were used to create patient groups by combining two or more multivariate significant risk factors for AKI. The EHRs dataset and HCT-AKIR score were created based on the multivariate analysis of the composite variables.

RESULTS

A multivariate analysis showed that previous CKD and once-impaired pre-transplant kidney function, sepsis, imaging procedures with contrast media, and cumulative length of intensive care unit stay after transplantation were significant risk factors. A new unit-weighted composite score based on the combination of significant risk factors contained in common EHR resources was proposed.

CONCLUSIONS

Using our novel HCT-AKIR score calculated from the basic EHR dataset could be an easy way to increase awareness of post-transplant AKI and provide risk stratification.

Testing the functional reserve of the kidney before hematopoietic stem cell transplantation: doubt remains

Acute kidney injury is a common and important complication following hematopoietic stem cell transplantation. In the nephrology community, acute kidney injury is no longer viewed as a simple temporary and potentially reversible decline in kidney clearance as acute kidney injury imposes a risk for immediate and future complications. Therefore, stratifying patients for the risk of acute kidney injury following stem cell transplantation would be very helpful to optimize peri-stem cell transplant management and could potentially improve outcomes in this patient population. In the current issue of CKJ, Mancianti et al. report on the testing of the kidney's functional reserve in patients planned for stem cell transplantation and demonstrate that stem cell transplant candidates with a preserved kidney response on a protein load had a higher chance of full kidney recovery after an episode of acute kidney injury. In this editorial, we discuss the kidney's functional reserve test and its limitations.

Endocrine sequelae of hematopoietic stem cell transplantation: Effects on mineral homeostasis and bone metabolism

Hematopoietic stem cell transplantation (HSCT) is an established therapeutic strategy for the treatment of malignant (leukemia and lymphoma) and non-malignant (thalassemia, anemia, and immunodeficiency) hematopoietic diseases. Thanks to the improvement in patient care and the development of more tolerable conditioning treatments, which has extended the applicability of therapy to the elderly, a growing number of patients have successfully benefited from HSCT therapy and, more importantly, HSCT transplant-related mortality has consistently reduced in recent years. However, concomitantly to long term patient survival, a growing incidence of late HSCT-related sequelae has been reported, being variably associated with negative effects on quality of life of patients and having a non-negligible impact on healthcare systems. The most predominantly observed HSCT-caused complications are chronic alterations of the endocrine system and metabolism, which endanger post-operative quality of life and increase morbidity and mortality of transplanted patients. Here, we specifically review the current knowledge on HSCT-derived side-effects on the perturbation of mineral metabolism; in particular, the homeostasis of calcium, focusing on current reports regarding osteoporosis and recurrent renal dysfunctions that have been observed in a percentage of HSC-transplanted patients. Possible secondary implications of conditioning treatments for HSCT on the physiology of the parathyroid glands and calcium homeostasis, alone or in association with HSCT-caused renal and bone defects, are critically discussed as well.

Recent Advances of Acute Kidney Injury in Hematopoietic Cell Transplantation

Acute kidney injury (AKI) is a common complication of allogeneic hematopoietic cell transplantation (allo-HCT) and is associated with non-relapse mortality (NRM) and quality of life (QOL). Multiple factors may contribute to AKI during allo-HCT and are often present at the same time making it difficult to determine the cause of AKI in each patient. Nephrotoxic drugs, infections, thrombotic microangiopathy (TMA), and sinusoidal obstruction syndrome (SOS) are well described causes of AKI during allo-HCT. Acute graft-versus-host disease (aGVHD) is a major complication of allo-HCT that mainly targets the intestines, liver, and skin. However, recent studies suggest aGVHD may also attack the kidney and contribute to AKI following allo-HCT. For example, severe aGVHD is associated with AKI, suggesting a link between the two. In addition, animal models have shown donor immune cell infiltration and increased expression of inflammatory cytokines in recipient kidneys after allo-HCT. Therefore, aGVHD may also target the kidney and contribute to AKI following allo-HCT. Herein, we describe the etiology, diagnosis, risk factors, pathophysiology, prevention, and treatment of renal injury after allo-HCT. In addition, we highlight emerging evidence that aGVHD may contribute to the development of AKI after allo-HCT.

Sequential Organ Failure Assessment Score and the Need for Organ Support Predict Mortality in Allogeneic Stem Cell Transplant Patients Admitted to the Intensive Care Unit

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective therapy resulting in increased definitive cure rates or extended disease-free survival in various malignant and nonmalignant hematologic diseases. However, because of the high risk of severe complications of this therapy, up to 50% of patients may require being admitted to the intensive care unit (ICU) to manage life-threatening conditions. We aimed to evaluate the in-hospital mortality of allo-HSCT recipients admitted to the ICU and to identify those variables associated with in-hospital mortality. A 10-year (January 2010 to December 2019), single-center, retrospective study was conducted in Vall d´Hebron University Hospital, Barcelona. We included all consecutive allo-HSCT patients who required admission to the ICU. Baseline and disease-related characteristics were registered. Severity scores and the need for organ support were also assessed on days 1, 3, and 5 of ICU admission. In-hospital mortality-associated independent variables were identified using the Cox proportional hazards regression model. Three hundred twenty-three patients underwent allo-HSCT during the study period, of whom 82 (25%) were admitted to the ICU; 53 (65%) male, with a median age of 51 (38-59) years. Most patients received allo-HSCT for the treatment of lymphoma (20 patients [24%]) or acute leukemia (44 patients [54%]). The median Acute Physiology And Chronic Health Evaluation II score was 23 (17-28), and the median Sequential Organ Failure Assessment (SOFA) score on admission was 9 (7-11). Forty-nine (60%) patients died in the ICU, and 11 (13%) died in the hospital after being discharged from the ICU. Disease-related characteristics were not associated with mortality. Yet, SOFA score on day 1 (hazard ratio [HR]: 1.11 [95% confidence interval {CI}: 1.04-1.02]; P = .002), the need for vasopressors on day 3 (HR: 2.35 [95% CI: 1.27-4.36]; P = .007), and a nondecreasing SOFA score on day 5 (HR: 2.13 [95% CI: 1.03-4.39]; P = .04), were independently associated with in-hospital mortality. Mortality in allo-HSCT patients who require ICU admission remains high. In the present study, SOFA score, the need for vasopressors on day 3, and a nondecreasing SOFA score on day 5 predicted in-hospital mortality.

Kidney Recovery From Acute Kidney Injury After Hematopoietic Stem Cell Transplant: A Systematic Review and Meta-Analysis

Patients with the recovery of kidney function after an episode of acute kidney injury (AKI) have better outcomes compared to those without recovery. The current systematic review is conducted to assess the rates of kidney function recovery among patients with AKI or severe AKI requiring kidney replacement therapy (KRT) within 100 days after hematopoietic stem cell transplant (HSCT). Methods The Ovid MEDLINE, EMBASE, and Cochrane databases were systemically searched from database inceptions through August 2019 to identify studies reporting the rates of recovery from AKI after HSCT. The random-effects and generic inverse variance methods of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies. Results A total of 458 patients from eight cohort studies with AKI after HSCT were identified. Overall, the pooled estimated rates of AKI recovery among patients with AKI and severe AKI requiring KRT within 100 days were 58% (95%CI: 37%-78%) and 10% (95%CI: 2%-4%), respectively. Among patients with AKI recovery, the pooled estimated rates of complete and partial AKI recovery were 60% (95%CI: 39%-78%) and 29% (95%CI: 10%-61%), respectively. There was no clear correlation between study year and the rate of AKI recovery (p=0.26). Conclusion The rate of recovery from AKI after HSCT depends on the severity of AKI. While recovery is common, complete recovery is reported in about two-thirds of all AKI patients. The rate of recovery among those with AKI requiring renal replacement therapy (RRT) is substantially lower.

Changing the terminology from kidney replacement therapy to kidney support therapy

Kidney replacement therapy (KRT) is a common supportive treatment for renal dysfunction, especially acute kidney injury. However, critically ill or immunosuppressed patients with renal dysfunction often have dysfunction in other organs as well. To improve patient outcomes, clinicians began to initiate kidney replacement therapy in situations where nonrenal conditions may lead to acute kidney injury, such as septic shock, hematopoietic stem cell transplantation, veno-occlusive renal disease, cardiopulmonary bypass, chemotherapy, tumor lysis syndrome, hyperammonemia, and various others. In this review, we discuss the use of various modes of kidney replacement therapy in treating renal and nonrenal complications to illustrate why kidney support therapy is a more appropriate terminology than kidney replacement therapy.

Incidence and mortality of acute kidney injury in patients undergoing hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

While acute kidney injury (AKI) is commonly reported following hematopoietic stem cell transplant (HCT), the incidence and impact of AKI on mortality among patients undergoing HCT are not well described. We conducted this systematic review to assess the incidence and impact of AKI on mortality risk among patients undergoing HCT.

METHODS

Ovid MEDLINE, EMBASE and the Cochrane Databases were searched from database inceptions through August 2019 to identify studies assessing the incidence of AKI and mortality risk among adult patients who developed AKI following HCT. Random-effects and generic inverse variance method of DerSimonian-Laird were used to combine the effect estimates obtained from individual studies.

RESULTS

We included 36 cohort studies with a total of 5144 patients undergoing HCT. Overall, the pooled estimated incidence of AKI and severe AKI (AKI Stage III) were 55.1% (95% confidence interval (CI) 46.6-63.3%) and 8.3% (95% CI 6.0-11.4%), respectively. The pooled estimated incidence of AKI using contemporary AKI definitions (RIFLE, AKIN and KDIGO criteria) was 49.8% (95% CI 41.6-58.1%). There was no significant correlation between study year and the incidence of AKI (P = 0.12) or severe AKI (P = 0.97). The pooled odds ratios of 3-month mortality and 3-year mortality among patients undergoing HCT with AKI were 3.05 (95% CI 2.07-4.49) and 2.23 (95% CI 1.06-4.73), respectively.

CONCLUSION

The incidence of AKI among patients who undergo HCT remains high, and it has not changed over the years despite advances in medicine. AKI after HCT is associated with increased short- and long-term mortality.

Independent risk factors and long-term outcomes for acute kidney injury in pediatric patients undergoing hematopoietic stem cell transplantation: a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) remains a frequent complication in children undergoing hematopoietic stem cell transplantation (HSCT) and an independent risk factor of the patient's survival and a prognostic factor of progression to chronic kidney disease (CKD). However, the causes of these complications are diverse, usually overlapping, and less well understood.

METHODS

This retrospective analysis was performed in 43 patients (28 boys, 15 girls; median age, 5.5 years) undergoing HSCT between April 2006 and March 2019. The main outcome was the development of AKI defined according to the Pediatric Risk, Injury, Failure, Loss, End-stage Renal Disease (pRIFLE) criteria as ≥ 25% decrease in estimated creatinine clearance. The secondary outcome was the development of CKD after a 2-year follow-up.

RESULTS

AKI developed in 21 patients (49%) within 100 days after HSCT. After adjusting for possible confounders, posttransplant AKI was associated with matched unrelated donor (MUD) (HR, 6.26; P = 0.042), but not total body irradiation (TBI). Of 37 patients who were able to follow-up for 2 years, 7 patients died, but none had reached CKD during the 2 years after transplantation.

CONCLUSIONS

Posttransplant AKI was strongly associated with HSCT from MUD. Although the incidence of AKI was high in our cohort, that of posttransplant CKD was lower than reported previously in adults. TBI dose reduced, GVHD minimized, and infection prevented are required to avoid late renal dysfunction after HSCT in children since their combinations may contribute to the occurrence of AKI.

Acute Kidney Injury and CKD Associated with Hematopoietic Stem Cell Transplantation

Hematopoietic stem cell transplantation is a life-saving therapy for many patients with cancer, as well as patients with some nonmalignant hematologic disorders, such as aplastic anemia, sickle cell disease, and certain congenital immune deficiencies. Kidney injury directly associated with stem cell transplantation includes a wide range of structural and functional abnormalities, which may be vascular (hypertension, thrombotic microangiopathy), glomerular (albuminuria, nephrotic glomerulopathies), and/or tubulointerstitial. AKI occurs commonly after stem cell transplant, affecting 10%-73% of patients. The cause is often multifactorial and can include sepsis, nephrotoxic medications, marrow infusion syndrome, hepatic sinusoidal obstruction syndrome, thrombotic microangiopathy, infections, and graft versus host disease. The risk of post-transplant kidney injury varies depending on patient characteristics, type of transplant (allogeneic versus autologous), and choice of chemotherapeutic conditioning regimen (myeloablative versus nonmyeloablative). Importantly, AKI is associated with substantial morbidity, including the need for KRT in approximately 5% of patients and the development of CKD in up to 60% of transplant recipients. AKI has been associated universally with higher all-cause and nonrelapse mortality regardless of transplant type, and studies have consistently shown extremely high (>80%) mortality rates in those patients requiring acute dialysis. Accordingly, prevention, early recognition, and prompt treatment of kidney injury are essential to improving kidney and patient outcomes after hematopoietic stem cell transplantation, and for realizing the full potential of this therapy.

Kidney dysfunction after hematopoietic cell transplantation-Etiology, management, and perspectives

Kidney dysfunction is a common complication of hematopoietic cell transplantation (HCT) with proven negative impact on early and long-term mortality. Causes of this complication are diverse, usually overlapping, and poorly understood. Therefore, management implicates multidirectional investigations and simultaneous treatment of suspected causes. The etiology is frequently unconfirmed due to a lack of specific markers and prevalence of contraindications to renal biopsy among HCT recipients. Herein, we provide a summary of etiology and propose an algorithm for evaluation of kidney injury after HCT. We also map out the most urgent areas for research that aim to identify patients at risk of severe renal injury and develop nephroprotective strategies.

Kidney Pathology after Hematologic Cell Transplantation-A Single-Center Observation Study of Indication Biopsies and Autopsies

Hematopoietic cell transplantation (HCT) is an increasingly used treatment for hematologic malignancies as well as for nonmalignant diseases. Kidney impairment remains an important early and late post-transplantation complication. Although numerous histopathological changes have been reported, the pathophysiology remains incompletely understood. Furthermore, correlations between clinical findings and morphological changes have not been well studied. Between 2000 and 2016, 17 recipients of allogeneic (n = 12) or autologous (n = 5) HCT underwent kidney biopsy for either proteinuria or deterioration of kidney function at our center. The most common biopsy findings were therapy-related changes with thrombotic microangiopathy (n = 5), calcineurin inhibitor toxicity (n = 4), and membranous glomerulonephritis (n = 3), representing the majority of cases in this category. In addition, kidney findings from 137 autopsies performed between 1995 and March 2017 were analyzed. The most common changes were acute kidney injury (n = 55), most likely due to the patients' premortal deteriorated state, and thrombotic microangiopathy (n = 14). Several cases demonstrated involvement by either infectious agents (n = 6) or tumors (n = 9). Distinct kidney diseases, such as glomerulonephritis, were rare (3% of cases). Uncommon and yet rarely described diagnoses for this patient cohort were IgG4-related tubulointerstitial nephritis and fibrillary nephritis. This study provides a comprehensive overview of the histomorphological findings in kidney biopsy specimens from HCT recipients. Along with treatment-related complications, one putative correlate of chronic GVHD of the kidney could be documented: membranous glomerulonephritis. In contrast, no morphological correlate of acute GVHD of the kidney was identified. Findings at the time of autopsy varied greatly, spanning a wider range than those of indication biopsies.

Acute kidney injury in hematological patients

PURPOSE OF REVIEW

The present article reviews the recent literature on the main aspects of acute kidney injury (AKI) developing in patients with hematological malignancies admitted to ICU.

RECENT FINDINGS

Up to two thirds of critically ill patients with hematological malignancies develop AKI. Current mortality rates range from 40 to 60% for most patients with hematological malignancies, except for recipients of allogeneic hematopoietic stem cell transplantation in whom outcomes remain very poor. Renal function recovery occurs in most patients with AKI, but is dependent on the underlying causes. AKI is usually multifactorial, resulting from causes common to other ICU patients and related to the underlying malignancy or its treatment. New targeted therapies and treatment strategies are potentially associated with AKI. Management of these patients requires a high degree of suspicion, close monitoring of metabolic parameters, and use of preventive strategies to limit risk of AKI or to mitigate its severity.

SUMMARY

AKI is a frequent and severe complication in critically ill patients with hematological malignancies. As the clinical management is complex, close collaboration with hematologists is paramount.

Critically ill allogeneic hematopoietic stem cell transplantation patients in the intensive care unit: reappraisal of actual prognosis

The outcome of allogeneic hematopoietic stem cell transplantation (allo-HSCT) patients has significantly improved over the past decade. Still, a significant number of patients require intensive care unit (ICU) management because of life-threatening complications. Literature from the 1990s reported extremely poor prognosis for critically ill allo-HSCT patients requiring ICU management. Recent data justify the use of ICU resources in hematologic patients. Yet, allo-HSCT remains an independent variable associated with mortality. However, outcomes in allo-HSCT patients have improved over time and many classic determinants of mortality have become irrelevant. The main actual prognostic factors are the need for mechanical ventilation, the presence of GvHD and the number of organ failures at ICU admission. Recently, the development of reduced-intensity conditioning regimens, early ICU admission and the increased use of noninvasive ventilation, combined with time effect and general advances in hematology, in allo-HSCT procedures and in ICU management have contributed to improve general outcome. A rational policy of ICU admission triage in these patients is very hard to define, as each decision for ICU admission is a case-by-case decision at patient bedside. The collaboration between hematologists and intensivists is crucial in this context.

Managing critically Ill hematology patients: Time to think differently

The number of patients living with hematological malignancies (HMs) has increased steadily over time. This is the result of intensive and effective treatments that also increase the probability of infiltrative, infectious or toxic life threatening event. Over the last two decades, the number of patients with HMs admitted to the ICU increased and their mortality has dropped sharply. ICU patients with HMs require an extensive diagnostic workup and the optimal use of ICU treatments to identify the reason for ICU admission and the nature of the complication that explains organ dysfunctions. Mortality of ARDS or septic shock is up to 50%, respectively. In this review, the authors share their experience with managing critically ill patients with HMs. They discuss the main aspects of the diagnostic and therapeutic management of critically ill patients with HMs and argue that outcomes have improved over time and that many classic determinants of mortality have become irrelevant.

Changes in intensive care for allogeneic hematopoietic stem cell transplant recipients

Intensive care unit (ICU) admission is associated with high mortality in allogeneic hematopoietic stem cell transplant (HSCT) recipients. Whether mortality has decreased recently is unknown. The 497 adult allogeneic HSCT recipients admitted to three ICUs between 1997 and 2011 were evaluated retrospectively. Two hundred and nine patients admitted between 1997 and 2003 were compared with the 288 patients admitted from 2004 to 2011. Factors associated with 90-day mortality were identified. The recent cohort was characterized by older age, lower conditioning intensity, and greater use of peripheral blood or unrelated-donor graft. In the recent cohort, ICU was used more often for patients in hematological remission (67% vs 44%; P<0.0001) and without GVHD (73% vs 48%; P<0.0001) or invasive fungal infection (85% vs 73%; P=0.0003) despite a stable admission rate (21.7%). These changes were associated with significantly better 90-day survival (49% vs 31%). Independent predictors of hospital mortality were GVHD, mechanical ventilation (MV) and renal replacement therapy (RRT). Among patients who required MV or RRT, survival was 29% and 18%, respectively, but dropped to 18% and 6% in those with GVHD. The use of ICU admission has changed and translated into improved survival, but advanced life support in patients with GVHD usually provides no benefits.