Acute kidney injury in patients with cirrhosis: Acute Disease Quality Initiative (ADQI) and International Club of Ascites (ICA) joint multidisciplinary consensus meeting.

Patients with cirrhosis are prone to developing acute kidney injury (AKI), a complication associated with a markedly increased in-hospital morbidity and mortality, along with a risk of progression to chronic kidney disease. Whereas patients with cirrhosis are at increased risk of developing any phenotype of AKI, hepatorenal syndrome (HRS), a specific form of AKI (HRS-AKI) in patients with advanced cirrhosis and ascites, carries an especially high mortality risk. Early recognition of HRS-AKI is crucial since administration of splanchnic vasoconstrictors may reverse the AKI and serve as a bridge to liver transplantation, the only curative option. In 2023, a joint meeting of the International Club of Ascites (ICA) and the Acute Disease Quality Initiative (ADQI) was convened to develop new diagnostic criteria for HRS-AKI, to provide graded recommendations for the work-up, management and post-discharge follow-up of patients with cirrhosis and AKI, and to highlight priorities for further research.

Impact of acute kidney injury response on survival and liver transplant rates in hospitalized patients with cirrhosis awaiting liver transplantation: Results from the HRS-HARMONY consortium.

BACKGROUND & AIMS: Acute kidney injury (AKI) frequently complicates the course of hospitalized patients with cirrhosis and negatively affects their prognosis. How AKI response influences the timing of liver transplantation (LT) remains unclear. We sought to assess the impact of AKI response to treatment on survival and LT rates in cirrhosis patients awaiting LT. APPROACH & RESULTS: This was a retrospective multicenter study of cirrhosis patients waitlisted for LT and hospitalized with AKI in 2019. The exposure was AKI response versus no response during hospitalization. Outcomes were 90-day overall and transplant-free survival, and rates of LT with time to transplant. We adjusted for age, sex, race, cirrhosis etiology, site, and MELD-Na score. Among the 317 patients in this study, 170 had AKI response (53.6%), and 147 had no response (46.4%). Compared to non-responders, responders had better 90-day overall survival (89.4% vs. 76.2%, adjusted sHR for mortality 0.34, p=0.001), and transplant-free survival (63.5% vs. 25.2%, aHR for probability of death or transplant 0.35, p<0.001). The LT rate was lower in responders (45.9% vs. 61.2%, adjusted sHR 0.55, p=0.005). 79% of transplants in responders occurred after discharge, at a median of 103 days, while 62% of transplants in non-responders occurred during hospitalization, with the remainder occurring post-discharge at a median of 58 days. CONCLUSIONS: In patients with cirrhosis waitlisted for LT who are hospitalized with AKI, AKI response to therapy is associated with improved 90-day survival, despite a reduced LT rate and longer time to LT.

Incidence and outcomes of acute kidney injury including hepatorenal syndrome in hospitalized patients with cirrhosis in the US.

BACKGROUND & AIMS: Acute kidney injury (AKI) in cirrhosis is common and associated with high morbidity, but the incidence rates of different etiologies of AKI are not well described in the US. We compared incidence rates, practice patterns, and outcomes across etiologies of AKI in cirrhosis. METHODS: We performed a retrospective cohort study of 11 hospital networks, including consecutive adult patients admitted with AKI and cirrhosis in 2019. The etiology of AKI was adjudicated based on pre-specified clinical definitions (prerenal/hypovolemic AKI, hepatorenal syndrome [HRS-AKI], acute tubular necrosis [ATN], other). RESULTS: A total of 2,063 patients were included (median age 62 [IQR 54-69] years, 38.3% female, median MELD-Na score 26 [19-31]). The most common etiology was prerenal AKI (44.3%), followed by ATN (30.4%) and HRS-AKI (12.1%); 6.0% had other AKI, and 7.2% could not be classified. In our cohort, 8.1% of patients received a liver transplant and 36.5% died by 90 days. The lowest rate of death was observed in patients with prerenal AKI (22.2%; p <0.001), while death rates were higher but not significantly different from each other in those with HRS-AKI and ATN (49.0% vs. 52.7%; p = 0.42). Using prerenal AKI as a reference, the adjusted subdistribution hazard ratio (sHR) for 90-day mortality was higher for HRS-AKI (sHR 2.78; 95% CI 2.18-3.54; p <0.001) and ATN (sHR 2.83; 95% CI 2.36-3.41; p <0.001). In adjusted analysis, higher AKI stage and lack of complete response to treatment were associated with an increased risk of 90-day mortality (p <0.001 for all). CONCLUSION: AKI is a severe complication of cirrhosis. HRS-AKI is uncommon and is associated with similar outcomes to ATN. The etiology of AKI, AKI stage/severity, and non-response to treatment were associated with mortality. Further optimization of vasoconstrictors for HRS-AKI and supportive therapies for ATN are needed. IMPACT AND IMPLICATIONS: Acute kidney injury (AKI) in cirrhosis carries high morbidity, and management is determined by the etiology of injury. However, a large and well-adjudicated multicenter database from US centers that uses updated AKI definitions is lacking. Our findings demonstrate that acute tubular necrosis and hepatorenal syndrome have similar outcomes (∼50% mortality at 90 days), though hepatorenal syndrome is uncommon (12% of all AKI cases). These findings represent practice patterns at US transplant/tertiary centers and can be used as a baseline, presenting the situation prior to the adoption of terlipressin in the US.

Terlipressin and the Treatment of Hepatorenal Syndrome: How the CONFIRM Trial Moves the Story Forward.

Hepatorenal syndrome (HRS) is a form of acute kidney injury (AKI) occurring in patients with advanced cirrhosis and is associated with significant morbidity and mortality. The pathophysiology underlying HRS begins with increasing portal pressures leading to the release of vasodilatory substances that result in pooling blood in the splanchnic system and a corresponding reduction in effective circulating volume. Compensatory activation of the sympathetic nervous system and the renin-angiotensin-aldosterone system and release of arginine vasopressin serve to defend mean arterial pressure but at the cost of severe constriction of the renal vasculature, leading to a progressive, often fulminant form of AKI. There are no approved treatments for HRS in the United States, but multiple countries, including much of Europe, use terlipressin, a synthetic vasopressin analogue, as a first-line therapy. CONFIRM (A Multi-Center, Randomized, Placebo Controlled, Double-Blind Study to Confirm Efficacy and Safety of Terlipressin in Subjects With Hepatorenal Syndrome Type 1), the third randomized trial based in North America evaluating terlipressin, met its primary end point of showing greater rates of HRS reversal in the terlipressin arm. However, due to concerns about the apparent increased rates of respiratory adverse events and a lack of evidence for mortality benefit, terlipressin was not approved by the Food and Drug Administration (FDA). We explore the history of regulatory approval for terlipressin in the United States, examine the results from CONFIRM and the concerns they raised, and consider the future role of terlipressin in this critical clinical area of continued unmet need.

A Genome-Wide Association Study to Identify Single-Nucleotide Polymorphisms for Acute Kidney Injury.

RATIONALE: Acute kidney injury is a common and severe complication of critical illness and cardiac surgery. Despite significant attempts at developing treatments, therapeutic advances to attenuate acute kidney injury and expedite recovery have largely failed. OBJECTIVES: Identifying genetic loci associated with increased risk of acute kidney injury may reveal novel pathways for therapeutic development. METHODS: We conducted an exploratory genome-wide association study to identify single-nucleotide polymorphisms associated with genetic susceptibility to in-hospital acute kidney injury. MEASUREMENTS AND MAIN RESULTS: We genotyped 609,508 single-nucleotide polymorphisms and performed genotype imputation in 760 acute kidney injury cases and 669 controls. We then evaluated polymorphisms that showed the strongest association with acute kidney injury in a replication patient population containing 206 cases with 1,406 controls. We observed an association between acute kidney injury and four single-nucleotide polymorphisms at two independent loci on metaanalysis of discovery and replication populations. These include rs62341639 (metaanalysis P = 2.48 × 10-7; odds ratio [OR], 0.64; 95% confidence interval [CI], 0.55-0.76) and rs62341657 (P = 3.26 × 10-7; OR, 0.65; 95% CI, 0.55-0.76) on chromosome 4 near APOL1-regulator IRF2, and rs9617814 (metaanalysis P = 3.81 × 10-6; OR, 0.70; 95% CI, 0.60-0.81) and rs10854554 (P = 6.53 × 10-7; OR, 0.67; 95% CI, 0.57-0.79) on chromosome 22 near acute kidney injury-related gene TBX1. CONCLUSIONS: Our findings reveal two genetic loci that are associated with acute kidney injury. Additional studies should be conducted to functionally evaluate these loci and to identify other common genetic variants contributing to acute kidney injury.

Urine Interleukin 18 and Lipocalin 2 Are Biomarkers of Acute Tubular Necrosis in Patients With Cirrhosis: A Systematic Review and Meta-analysis.

BACKGROUND & AIMS: Acute kidney injury (AKI) is a common complication in patients with cirrhosis that increases mortality. The most common causes of AKI in these patients are prerenal azotemia, acute tubular necrosis (ATN), and hepatorenal syndrome; it is important to determine the etiology of AKI to select the proper treatment and predict patient outcome. Urine biomarkers could be used to differentiate between patients with ATN and functional causes of AKI. We performed a systematic review and meta-analysis of published studies to determine whether urine levels of interleukin (IL)18 and lipocalin 2 or neutrophil gelatinase-associated lipocalin (NGAL) are associated with the development of ATN in patients with cirrhosis. METHODS: We searched MEDLINE, Scopus, ISI Web of Knowledge, and conference abstracts through December 31, 2015, for studies that assessed urine biomarkers for detection of acute kidney injury in patients with cirrhosis or reported an association between urine biomarkers and all-cause mortality in these patients. We included only biomarkers assessed in 3 or more independent studies, searching for terms that included urine biomarkers, cirrhosis, NGAL, and IL18. We calculated the pooled sensitivities and specificities for detection and calculated the area under the receiver operating characteristic curve (AUC) values using a bivariate logistic mixed-effects model. We used the χ2 test to assess heterogeneity among studies. RESULTS: We analyzed data from 8 prospective studies, comprising 1129 patients with cirrhosis. We found urine levels of the markers discriminated between patients with ATN and other types of kidney impairments, with AUC values of 0.88 for IL18 (95% confidence interval [CI], 0.79-0.97) and 0.89 for NGAL (95% CI, 0.84-0.94). Urine levels of IL18 identified patients who would die in the hospital or within 90 days (short-term mortality) with an AUC value of 0.76 (95% CI, 0.68-0.85); NGAL identified these patients with the same AUC (0.76; 95% CI, 0.71-0.82). CONCLUSIONS: In a systematic review and meta-analysis, we found that urine levels of IL18 and NGAL from patients with cirrhosis discriminate between those with ATN and other types of kidney impairments, with AUC values of 0.88 and 0.89, respectively. Urine levels of IL18 and NGAL identified patients with short-term mortality with an AUC value of 0.76. These biomarkers might be used to determine prognosis and select treatments for patients with cirrhosis.

Kidney biomarkers and differential diagnosis of patients with cirrhosis and acute kidney injury.

UNLABELLED: Acute kidney injury (AKI) is common in patients with cirrhosis and associated with significant mortality. The most common etiologies of AKI in this setting are prerenal azotemia (PRA), acute tubular necrosis (ATN), and hepatorenal syndrome (HRS). Accurately distinguishing the etiology of AKI is critical, as treatments differ markedly. However, establishing an accurate differential diagnosis is extremely challenging. Urinary biomarkers of kidney injury distinguish structural from functional causes of AKI and may facilitate more accurate and rapid diagnoses. We conducted a multicenter, prospective cohort study of patients with cirrhosis and AKI assessing multiple biomarkers for differential diagnosis of clinically adjudicated AKI. Patients (n = 36) whose creatinine returned to within 25% of their baseline within 48 hours were diagnosed with PRA. In addition, 76 patients with progressive AKI were diagnosed by way of blinded retrospective adjudication. Of these progressors, 39 (53%) patients were diagnosed with ATN, 19 (26%) with PRA, and 16 (22%) with HRS. Median values for neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), kidney injury molecule-1 (KIM-1), liver-type fatty acid binding protein (L-FABP), and albumin differed between etiologies and were significantly higher in patients adjudicated with ATN. The fractional excretion of sodium (FENa) was lowest in patients with HRS, 0.10%, but did not differ between those with PRA, 0.27%, or ATN, 0.31%, P = 0.54. The likelihood of being diagnosed with ATN increased step-wise with the number of biomarkers above optimal diagnostic cutoffs. CONCLUSION: Urinary biomarkers of kidney injury are elevated in patients with cirrhosis and AKI due to ATN. Incorporating biomarkers into clinical decision making has the potential to more accurately guide treatment by establishing which patients have structural injury underlying their AKI. Further research is required to document biomarkers specific to HRS.

Association of AKI with mortality and complications in hospitalized patients with cirrhosis.

UNLABELLED: Acute kidney injury (AKI) is a common and devastating complication in patients with cirrhosis. However, the definitions of AKI employed in studies involving patients with cirrhosis have not been standardized, lack sensitivity, and are often limited to narrow clinical settings. We conducted a multicenter, prospective observational cohort study of patients with cirrhosis and AKI, drawn from multiple hospital wards, utilizing the modern acute kidney injury network (AKIN) definition and assessed the association between AKI severity and progression with in-hospital mortality. Of the 192 patients who were enrolled and included in the study, 85 (44%) progressed to a higher AKIN stage after initially fulfilling AKI criteria. Patients achieved a peak severity of AKIN stage 1, 26%, stage 2, 24%, and stage 3, 49%. The incidence of mortality, general medical events (bacteremia, pneumonia, urinary tract infection), and cirrhosis-specific complications (ascites, encephalopathy, spontaneous bacterial peritonitis) increased with severity of AKI. Progression was significantly more common and peak AKI stage higher in nonsurvivors than survivors (P < 0.0001). After adjusting for baseline renal function, demographics, and critical hospital- and cirrhosis-associated variables, progression of AKI was independently associated with mortality (adjusted odds ratio = 3.8, 95% confidence interval 1.3-11.1). CONCLUSION: AKI, as defined by AKIN criteria, in patients with cirrhosis is frequently progressive and severe and is independently associated with mortality in a stage-dependent fashion. Methods for earlier diagnosis of AKI and its progression may result in improved outcomes by facilitating targeted and timely treatment of AKI.

Hepatorenal Syndrome Type 1: Diagnosis and Treatment.

Hepatorenal syndrome (HRS) is a feared complication in patients with advanced cirrhosis and is associated with significant morbidity and mortality. While recognized as a distinct physiologic condition for well over one hundred years, a lack of objective diagnostic tests has made the diagnosis one of exclusion. Since 1979, multiple sets of diagnostic criteria have been proposed. Though varying in detail, the principal intent of these criteria is to identify patients with severe, functional acute kidney injury that is unresponsive to volume resuscitation and exclude those with structural injury. However, accurate differential diagnosis remains challenging. Recently, multiple urinary biomarkers of kidney injury, including neutrophil gelatinase-associated lipocalin, have been studied as a means of objectively phenotyping etiologies of acute kidney injury in patients with cirrhosis. Along with markers reflecting tubular functional integrity, including the fractional excretion of sodium, injury markers will likely be incorporated into future diagnostic criteria. Making an accurate diagnosis is critical, as therapeutic options exist for HRS but must be given in a timely manner and only to those patients likely to benefit. Terlipressin, an analog of vasopressin, is the first line of therapy for HRS in much of the world and has recently been approved for use in the United States. Significant questions remain regarding the optimal dosing strategy, metrics for titration, and the potential role of point-of-care ultrasound to help guide concurrent albumin administration.

Outcomes of patients with alcohol-associated hepatitis and acute kidney injury - Results from the HRS Harmony Consortium.

BACKGROUND & AIMS: The development of acute kidney injury (AKI) in the setting of alcohol-associated hepatitis (AH) portends a poor prognosis. Whether the presence of AH itself drives worse outcomes in patients with cirrhosis and AKI is unknown. METHODS: Retrospective cohort study of 11 hospital networks of consecutive adult patients admitted in 2019 with cirrhosis and AKI. AKI phenotypes, clinical course, and outcomes were compared between AH and non-AH groups. RESULTS: A total of 2062 patients were included, of which 303 (15%) had AH, as defined by National Institute on Alcohol Abuse and Alcoholism (NIAAA) criteria. Patients with AH, compared to those without, were younger and had higher Model for End-stage Liver Disease-Sodium (MELD-Na) scores on admission. AKI phenotypes significantly differed between groups (p < 0.001) with acute tubular necrosis occurring more frequently in patients with AH. Patients with AH reached more severe peak AKI stage, required more renal replacement therapy, and had higher 90-day cumulative incidence of death (45% [95% CI: 39%-51%] vs. 38% [95% CI: 35%-40%], p = 0.026). Using no AH as reference, the unadjusted sHR for 90-day mortality was higher for AH (sHR: 1.24 [95% CI: 1.03-1.50], p = 0.024), but was not significant when adjusting for MELD-Na, age and sex. However, in patients with hepatorenal syndrome, AH was an independent predictor of 90-day mortality (sHR: 1.82 [95% CI: 1.16-2.86], p = 0.009). CONCLUSIONS: Hospitalised patients with cirrhosis and AKI presenting with AH had higher 90-day mortality than those without AH, but this may have been driven by higher MELD-Na rather than AH itself. However, in patients with hepatorenal syndrome, AH was an independent predictor of mortality.

Acute kidney injury in patients with cirrhosis: perils and promise.

A 62-year-old man with cirrhosis secondary to hepatitis C and chronic alcohol abuse was admitted to the intensive care unit with hematemesis and mental status changes. Physical examination showed ascites and stigmata of chronic liver disease. Blood pressure was noted as 87/42 mm Hg and laboratory studies showed a serum creatinine level of 0.8 mg/dL, an estimated glomerular filtration rate of 84 mL/min/1.73 m(2) calculated using the Modification of Diet in Renal Disease Study equation, a serum sodium level of 123 mEq/L, a total serum bilirubin level of 4.3 mg/dL, and an international normalization ratio of 1.6. The patient was resuscitated with packed red blood cells and fresh-frozen plasma and bleeding was controlled. However, on the third day of admission, creatinine level increased to 1.5 mg/dL. Examination of urine sediment showed 1 to 5 bilirubin-stained granular casts per high-powered field and a few renal tubular epithelial cells. The urine sodium level was 21 mEq/L and the fractional excretion of sodium was 0.43%.

Hepatorenal Syndrome: Pathophysiology, Diagnosis, and Treatment.

Hepatorenal syndrome (HRS) is a primarily functional form of acute kidney injury (AKI) that develops in patients with decompensated cirrhosis. The pathophysiologic cascade that leads to HRS begins with pooling of blood in the splanchnic system, resulting in a decrease in effective circulating arterial volume. The definitive treatment of HRS is liver transplantation. When this is not possible, HRS is treated with a combination of vasoconstrictor agents and intravenous albumin. Although the combination of midodrine and octreotide is used in the United States, the recently approved terlipressin, an analog of vasopressin, is likely to become the first-line standard of care.

Clinical applications of biomarkers for acute kidney injury.

Research into novel therapies for acute kidney injury (AKI) has been hampered by reliance on a diagnosis predicated on changes in serum creatinine level. As a marker for changing kidney function rather than frank kidney injury, creatinine level lacks sensitivity and specificity for the diagnosis of AKI and shows significant lag time before increasing after injury. It has been unclear whether the failure to translate promising results from animal studies in AKI into successful human trials has been caused by lack of therapeutic efficacy or inappropriately delayed application of the intervention. Multiple novel biomarkers with the potential to revolutionize the timing and accuracy of the diagnosis of AKI currently are under investigation. We have chosen to use one of these biomarkers, interleukin 18 (IL-18), to show the ways in which biomarkers at present can supplement the conventional management of AKI. IL-18 is well suited for this analysis because it is both a mediator of and marker for AKI. We describe 2 cases in which reliance on serum creatinine level for the diagnosis of AKI led to diagnostic and management uncertainty. In the context of these cases, we discuss how IL-18 and other biomarkers can facilitate earlier detection, enhance the differential diagnosis, and allow more prescient prognosis. Additionally, we describe the potential role for biomarkers in prospective trial design and discuss the utility of biomarkers in facilitating adequate powering of trials through more accurate characterization of cases and controls.

Urinary NGAL as a Diagnostic and Prognostic Marker for Acute Kidney Injury in Cirrhosis: A Prospective Study.

INTRODUCTION: Urinary neutrophil gelatinase-associated lipocalin (NGAL) has shown promise in differentiating acute tubular necrosis (ATN) from other types of acute kidney injuries (AKIs) in cirrhosis, particularly hepatorenal syndrome (HRS). However, NGAL is not currently available in clinical practice in North America. METHODS: Urinary NGAL was measured in a prospective cohort of 213 US hospitalized patients with decompensated cirrhosis (161 with AKI and 52 reference patients without AKI). NGAL was assessed for its ability to discriminate ATN from non-ATN AKI and to predict 90-day outcomes. RESULTS: Among patients with AKI, 57 (35%) had prerenal AKI, 55 (34%) had HRS, and 49 (30%) had ATN, with a median serum creatinine of 2.0 (interquartile range 1.5, 3.0) mg/dL at enrollment. At an optimal cutpoint of 244 µg/g creatinine, NGAL distinguished ATN (344 [132, 1,429] µg/g creatinine) from prerenal AKI (45 [0, 154] µg/g) or HRS (110 [50, 393] µg/g; P < 0.001), with a C statistic of 0.762 (95% confidence interval 0.682, 0.842). By 90 days, 71 of 213 patients (33%) died. Higher median NGAL was associated with death (159 [50, 865] vs 58 [0, 191] µg/g; P < 0.001). In adjusted and unadjusted analysis, NGAL significantly predicted 90-day transplant-free survival (P < 0.05 for all Cox models) and outperformed Model for End-Stage Liver Disease score by C statistic (0.697 vs 0.686; P = 0.04), net reclassification index (37%; P = 0.008), and integrated discrimination increment (2.7%; P = 0.02). DISCUSSION: NGAL differentiates the type of AKI in cirrhosis and may improve prediction of mortality; therefore, it holds potential to affect management of AKI in cirrhosis.