Short and long-term outcome of patients with severe acute kidney injury requiring renal replacement therapy

The Urine Light Chain/eGFR Quotient as a Tool to Rule out Cast Nephropathy in Myeloma-Associated Kidney Failure

Kidney involvement with resulting kidney failure leads to increased mortality in patients with multiple myeloma (MM). Cast nephropathy (CN), in particular, if left untreated, quickly leads to kidney failure requiring dialysis and has a very poor prognosis for the affected patient. The gold standard for diagnosing kidney involvement is a kidney biopsy. However, due to bleeding risk, this cannot be done in every patient. We recently reported that a quotient of urine light chain (LCurine) to glomerular filtration rate (eGFR) is a non-invasive diagnostic tool for patients with kidney involvement in MM. But this quotient has not yet been tested in everyday clinical practice. In this study, our LCurine/eGFR ratio was tested on 67 patients in two centers. Enrollment took place between January 2019 and September 2023. A total of 18 of the 67 patients had CN. With the threshold defined in our initial paper, we were able to show a sensitivity of 100% with a specificity of 85.7% for CN in patients with MM. As a result, the LCurine/eGFR quotient recognizes 100% of all CN and can therefore detect this group, which has a very poor prognosis, without the need for a kidney biopsy.

Early transthoracic echocardiography and long-term mortality in moderate- to-severe acute respiratory distress syndrome: An analysis of the Medical Information Mart for Intensive Care database

BACKGROUND

The clinical use of transthoracic echocardiography (TTE) in patients with acute respiratory distress syndrome (ARDS) in the intensive care unit (ICU) has dramatically increased, its impact on long-term prognosis in these patients has not been studied. This study aimed to explore the effect of early-TTE on long-term mortality in patients with moderate-to-severe ARDS in ICU.

METHODS

A total of 2833 patients with moderate-to-severe ARDS who had or had not received early-TTE were obtained from the Medical Information Mart for Intensive Care (MIMIC-III) database after imputing missing values by a random forest model, patients were divided into early-TTE group and non-early-TTE group according to whether they received TTE examination in ICU. A variety of statistical methods were used to balance 41 covariates and increase the reliability of this study, including propensity score matching, inverse probability of treatment weight, covariate balancing propensity score, multivariable regression, and doubly robust estimation. Chi-Square test and t-tests were used to examine the differences between groups for categorical and continuous data, respectively.

RESULTS

There was a significant improvement in 90-day mortality in the early-TTE group compared to non-early-TTE group (odds ratio  =  0.79, 95% CI: 0.64-0.98, p-value  =  0.036), revealing a beneficial effect of early-TTE. Net-input was significantly decreased in the early-TTE group on the third day of ICU admission and throughout the ICU stay, compared with non-early-TTE group (838.57 vs. 1181.89 mL, p-value  =  0.014; 4542.54 vs. 8025.25 mL, p-value  =  0.05). There was a significant difference in the reduction of serum lactate between the two groups, revealing the beneficial effect of early-TTE (0.59 vs. 0.83, p-value  =  0.009). Furthermore, the reduction in the proportion of acute kidney injury demonstrated a correlation between early-TTE and kidney protection (33% vs. 40%, p-value < 0.001).

CONCLUSIONS

Early application of TTE is beneficial to improve the long-term mortality of patients with moderate-to-severe ARDS.

The urine light chain/glomerular filtration rate (GFR) quotient shows a high sensitivity and specificity to detect cast nephropathy in monoclonal light chain disease

BACKGROUND

Cast nephropathy (CN) is associated with a unfavourable outcome in monoclonal light chain (mLC) disease, but also more possible LC-related renal diseases as well as non-LC-related disease can occur. Thus, it is crucial to understand the underlying renal disease. On the other hand, LC can interfere with coagulation preventing kidney biopsy as the gold standard. We sought to develop a non-invasive algorithm to diagnose CN with a good sensitivity and specificity.

METHOD

We analysed data from patients with mLC disease who underwent kidney biopsy. The patients were classified in 4 groups according the renal histology: CN, AL amyloidosis, light chain deposition disease, and other renal disease. Afterwards, different algorithms were calculated for their sensitivity and specificity.

RESULTS

CN showed a significant higher concentration of serum-free LC and urine LC (LCu), but there was a wide and overlapping range with the other groups. The best accuracy was achieved for a LCu/GFR ratio >2 in patients with lambda LC and either a LCu/GFR > 1 and proteinuria <8 g/24 h or a LCu/GFR > 5 in patients with proteinuria >8 g/24 h in patients with kappa LC. In lambda LC, the sensitivity and specificity for CN was 94% and 90%, respectively; in kappa LC 87% and 81%, respectively.

DISCUSSION

In patients with coagulation disturbances due to LC, a non-invasive algorithm can separate patients with CN from other renal disease in mLC disease.

Decision-making around admission to intensive care in the UK pre-COVID-19: a multicentre ethnographic study

Predicting who will benefit from admission to an intensive care unit is not straightforward and admission processes vary. Our aim was to understand how decisions to admit or not are made. We observed 55 decision-making events in six NHS hospitals. We interviewed 30 referring and 43 intensive care doctors about these events. We describe the nature and context of the decision-making and analysed how doctors make intensive care admission decisions. Such decisions are complex with intrinsic uncertainty, often urgent and made with incomplete information. While doctors aspire to make patient-centred decisions, key challenges include: being overworked with lack of time; limited support from senior staff; and a lack of adequate staffing in other parts of the hospital that may be compromising patient safety. To reduce decision complexity, heuristic rules based on experience are often used to help think through the problem; for example, the patient's functional status or clinical gestalt. The intensive care doctors actively managed relationships with referring doctors; acted as the hospital generalist for acutely ill patients; and brought calm to crisis situations. However, they frequently failed to elicit values and preferences from patients or family members. They were rarely explicit in balancing burdens and benefits of intensive care for patients, so consistency and equity cannot be judged. The use of a framework for intensive care admission decisions that reminds doctors to seek patient or family views and encourages explicit balancing of burdens and benefits could improve decision-making. However, a supportive, adequately resourced context is also needed.

Impact of Early Acute Kidney Injury on Management and Outcome in Patients With Acute Respiratory Distress Syndrome: A Secondary Analysis of a Multicenter Observational Study

OBJECTIVES

To understand the impact of mild-moderate and severe acute kidney injury in patients with acute respiratory distress syndrome.

DESIGN

Secondary analysis of the "Large Observational Study to Understand the Global Impact of Severe Acute Respiratory Failure", an international prospective cohort study of patients with severe respiratory failure.

SETTING

Four-hundred fifty-nine ICUs from 50 countries across five continents.

SUBJECTS

Patients with a glomerular filtration rate greater than 60 mL/min/1.73 m prior to admission who fulfilled criteria of acute respiratory distress syndrome on day 1 and day 2 of acute hypoxemic respiratory failure.

INTERVENTIONS

Patients were categorized based on worst serum creatinine or urine output into: 1) no acute kidney injury (serum creatinine < 132 µmol/L or urine output ≥ 0.5 mL/kg/hr), 2) mild-moderate acute kidney injury (serum creatinine 132-354 µmol/L or minimum urine output between 0.3 and 0.5mL/kg/hr), or 3) severe acute kidney injury (serum creatinine > 354 µmol/L or renal replacement therapy or minimum urine output < 0.3 mL/kg/hr).

MEASUREMENTS AND MAIN RESULTS

The primary outcome was hospital mortality, whereas secondary outcomes included prevalence of acute kidney injury and characterization of acute respiratory distress syndrome risk factors and illness severity patterns, in patients with acute kidney injury versus no acute kidney injury. One-thousand nine-hundred seventy-four patients met inclusion criteria: 1,209 (61%) with no acute kidney injury, 468 (24%) with mild-moderate acute kidney injury, and 297 (15%) with severe acute kidney injury. The impact of acute kidney injury on the ventilatory management of patients with acute respiratory distress syndrome was relatively limited, with no differences in arterial CO2 tension or in tidal or minute ventilation between the groups. Hospital mortality increased from 31% in acute respiratory distress syndrome patients with no acute kidney injury to 50% in mild-moderate acute kidney injury (p ≤ 0.001 vs no acute kidney injury) and 58% in severe acute kidney injury (p ≤ 0.001 vs no acute kidney injury and mild-moderate acute kidney injury). In multivariate analyses, both mild-moderate (odds ratio, 1.61; 95% CI, 1.24-2.09; p < 0.001) and severe (odds ratio, 2.13; 95% CI, 1.55-2.94; p < 0.001) acute kidney injury were independently associated with mortality.

CONCLUSIONS

The development of acute kidney injury, even when mild-moderate in severity, is associated with a substantial increase in mortality in patients with acute respiratory distress syndrome.

Antimicrobial therapy with aminoglycoside or meropenem in the intensive care unit for hospital associated infections and risk factors for acute kidney injury

There have historically been concerns of acute kidney injury (AKI) with the use of aminoglycosides. The present study aimed to compare the AKI incidence and mortality rate between critically ill patients treated with aminoglycoside or meropenem in the intensive care unit setting using a propensity score matching approach. This cross-sectional study was conducted at two university hospitals from January 2011 to October 2017. Clinical and laboratorial data were evaluated to exclude potential confounders and to calculate the Charlson index. AKI was classified according to the Acute Kidney Injury Network criteria. All tests were two-tailed, and a p value ≤ 0.05 was considered significant in the univariate and multivariate analyses. We included 494 patients, 95 and 399 of whom used meropenem and aminoglycoside, respectively. Patients in the subgroup that used meropenem were matched with controls (aminoglycoside). Among the 494 patients, 120 developed any grade of AKI (24.2%). After propensity score matching, there were no significant differences in AKI incidence and mortality rate between the aminoglycoside and meropenem groups (p = 0.324 and 0.464, respectively). Patients on the aminoglycoside regimen neither presented a higher AKI incidence nor mortality rate when compared with those on the meropenem regimen. Aminoglycosides may be a safe option for the treatment of critically ill patients on carbapenem sparing antimicrobial stewardship programs.

Developing an intervention around referral and admissions to intensive care: a mixed-methods study

Background

Intensive care treatment can be life-saving, but it is invasive and distressing for patients receiving it and it is not always successful. Deciding whether or not a patient will benefit from intensive care is a difficult clinical and ethical challenge.

Objectives

To explore the decision-making process for referral and admission to the intensive care unit and to develop and test an intervention to improve it.

Methods

A mixed-methods study comprising (1) two systematic reviews investigating the factors associated with decisions to admit patients to the intensive care unit and the experiences of clinicians, patients and families; (2) observation of decisions and interviews with intensive care unit doctors, referring doctors, and patients and families in six NHS trusts in the Midlands, UK; (3) a choice experiment survey distributed to UK intensive care unit consultants and critical care outreach nurses, eliciting their preferences for factors used in decision-making for intensive care unit admission; (4) development of a decision-support intervention informed by the previous work streams, including an ethical framework for decision-making and supporting referral and decision-support forms and patient and family information leaflets. Implementation feasibility was tested in three NHS trusts; (5) development and testing of a tool to evaluate the ethical quality of decision-making related to intensive care unit admission, based on the assessment of patient records. The tool was tested for inter-rater and intersite reliability in 120 patient records.

Results

Influences on decision-making identified in the systematic review and ethnographic study included age, presence of chronic illness, functional status, presence of a do not attempt cardiopulmonary resuscitation order, referring specialty, referrer seniority and intensive care unit bed availability. Intensive care unit doctors used a gestalt assessment of the patient when making decisions. The choice experiment showed that age was the most important factor in consultants’ and critical care outreach nurses’ preferences for admission. The ethnographic study illuminated the complexity of the decision-making process, and the importance of interprofessional relationships and good communication between teams and with patients and families. Doctors found it difficult to articulate and balance the benefits and burdens of intensive care unit treatment for a patient. There was low uptake of the decision-support intervention, although doctors who used it noted that it improved articulation of reasons for decisions and communication with patients.

Limitations

Limitations existed in each of the component studies; for example, we had difficulty recruiting patients and families in our qualitative work. However, the project benefited from a mixed-method approach that mitigated the potential limitations of the component studies.

Conclusions

Decision-making surrounding referral and admission to the intensive care unit is complex. This study has provided evidence and resources to help clinicians and organisations aiming to improve the decision-making for and, ultimately, the care of critically ill patients.

Future work

Further research is needed into decision-making practices, particularly in how best to engage with patients and families during the decision process. The development and evaluation of training for clinicians involved in these decisions should be a priority for future work.

Study registration

The systematic reviews of this study are registered as PROSPERO CRD42016039054, CRD42015019711 and CRD42015019714.

Funding

The National Institute for Health Research Health Services and Delivery Research programme. The University of Aberdeen and the Chief Scientist Office of the Scottish Government Health and Social Care Directorates fund the Health Economics Research Unit.

Long-term outcome of severe acute kidney injury survivors followed by nephrologists in a developing country

AIM

This study aimed to evaluate the long-term outcome of patients after a severe episode of acute kidney injury (AKI) on survival and progression to chronic kidney disease (CKD) and to identify risk factors associated with these outcomes.

METHODS

We performed a prospective study that evaluated the long-term outcome of 509 AKI stage 3 patients who were followed by nephrologists in a Brazilian University Hospital from 2004 to 2013.

RESULTS

Age was 60.2 years (47.5-71) and the follow-up time was 25 months (12-44). The late mortality was 38.1% and age (HR 2.89, 95% CI=1.88 to 4.46, P < 0.0001), diabetes (HR 1.46, 95% CI=1 0.02 to 2.16, P < 0.047), liver disease (HR 2.95, 95% CI=1.19 to 7.3, P = 0.02) and creatinine (Cr) at the time of hospital discharge (HR 1.21, 95% CI=1.04 to 1.41, P = 0.01) were associated with poor long-term survival. At the moment of hospital discharge, 52.1% of patients had complete recovery of renal function, 39.7% had partial recovery and 8.3% had not recovered renal function. After 36 months, 43.5% of patients progressed to CKD, and 5.3% needed for chronic dialysis. Factors associated with progression to CKD were age (HR 1.02, 95% CI=1.008 to 1.035, P = 0.009), CKD (HR 1.05 95% CI=1.007 to 1.09, P = 0.04), diabetes (HR 1.12, CI 1.008-1.035, P = 0.009) and number of AKI episodes (HR 1.65, 95% CI=1.19 to 2.2, P = 0.0023).

CONCLUSION

This study showed that AKI patients have high mortality after hospital discharge and age, diabetes, liver disease, and Cr value at the time of discharge were factors associated with long-term mortality. The risk factors for this progression to CKD were age, the presence of diabetes and the number of AKI episodes.

Duration of anuria predicts recovery of renal function after acute kidney injury requiring continuous renal replacement therapy

BACKGROUND/AIMS

Little is known regarding the incidence rate of and factors associated with developing chronic kidney disease after continuous renal replacement therapy (CRRT) in acute kidney injury (AKI) patients. We investigated renal outcomes and the factors associated with incomplete renal recovery in AKI patients who received CRRT.

METHODS

Between January 2011 and November 2013, 408 patients received CRRT in our intensive care unit. Of them, patients who had normal renal function before AKI and were discharged without maintenance renal replacement therapy (RRT) were included in this study. We examined the incidence of incomplete renal recovery with an estimated glomerular filtration rate < 60 mL/min/1.73 m(2) and factors that increased the risk of incomplete renal recovery after AKI.

RESULTS

In total, 56 AKI patients were discharged without further RRT and were followed for a mean of 8 months. Incomplete recovery of renal function was observed in 20 of the patients (35.7%). Multivariate analysis revealed old age and long duration of anuria as independent risk factors for incomplete renal recovery (odds ratio [OR], 1.231; 95% confidence interval [CI], 1.041 to 1.457; p = 0.015 and OR, 1.064; 95% CI, 1.001 to 1.131; p = 0.047, respectively). In a receiver operating characteristic curve analysis, a cut-off anuria duration of 24 hours could predict incomplete renal recovery after AKI with a sensitivity of 85.0% and a specificity of 66.7%.

CONCLUSIONS

The renal outcome of severe AKI requiring CRRT was poor even in patients without further RRT. Long-term monitoring of renal function is needed, especially in severe AKI patients who are old and have a long duration of anuria.

Outcome in noncritically ill patients with acute kidney injury requiring dialysis: Effects of differing medical staffs and organizations

Acute kidney injury requiring dialysis (AKI-D) treatment has significantly increased in incidence over the years, with more than 400 new cases per million population/y, 2/3 of which concern noncritically ill patients. In these patients, there are little data on mortality or on information of care organization and its impact on outcome. Specialty training and integrated teams, as well as a high volume of activity, seem to be linked to better hospital outcome. The study investigates mortality of patients admitted to and in-care of nephrology (NEPHROpts), a closed-staff organization, and to other medical wards (MEDpts), representing a model of open-staff organization.This is a single center, case-control cohort study derived from a prospective epidemiology investigation on patients with AKI-D admitted to or in-care of the Hospital of Perugia during the period 2007 to 2014. Noncritically ill AKI-D patients were analyzed: inclusion and exclusion criteria were defined to avoid possible bias on the cause of hospital admittance and comorbidities, and a propensity score (PS) matching was performed.Six hundred fifty-four noncritically ill patients were observed and 296 fulfilled inclusion/exclusion criteria. PS matching resulted in 2 groups: 100 NEPHROpts and 100 MEDpts. Characteristics, comorbidities, acute kidney injury causes, risk-injury-failure acute kidney injury criteria, and simplified acute physiology score (SAPS 2) were similar. Mortality was 36%, and a difference was reported between NEPHROpts and MEDpts (20% vs 52%, χ = 23.2, P < 0.001). Patients who died differed in age, serum creatinine, blood urea nitrogen/s.Creatinine ratio, dialysis urea reduction rate (URR), SAPS 2 and Charlson score; they presented a higher rate of heart disease, and a larger proportion required noradrenaline/dopamine for shock. After correction for mortality risk factors, multivariate Cox analysis revealed that site of treatment (medical vs nephrology wards) represents an independent risk factor of mortality (relative risk = 2.13, 95% confidence interval = 1.25, 3.63; P < 0.01). Other independent risk factors were age, URR, s.Creatinine at hemodialysis beginning, and SAPS 2 score.In our context, we have documented that noncritically ill AKI-D patients, who represented 2/3 of the population, had high in-hospital mortality (36%), and that a closed-staff specialty medical organization, such as a Nephrology team, seems to guarantee a better outcome than general medical organizations. The significance in healthcare system organization and resource allocation could be important.

Changes of etiology, incidence and outcomes of severe acute kidney injury during a 12-year period (2001-2012) in large university hospital

BACKGROUND

Despite improvement in the quality of critical care, the incidence and mortality of acute kidney injury (AKI) continues to rise. The aim of our study was to analyze the changes during a 12-year period in etiology, incidence and outcomes of severe AKI, which required dialysis, in a large single centre.

METHODS

We performed retrospective analysis of all the patients (n=3215) with severe AKI hospitalized and dialysed in the hospital of Lithuanian university of health sciences Kauno Klinikos (HLUHS KK) during the period of 2001-2012.

RESULTS

During a 12-year period, the incidence of severe AKI increased from 154 to 597 cases/p.m.p. The mean age of the patients increased from 58.2±19.2 years in 2001 to 65.7±17 years in 2012 (P<0.001). The number of men (n=2012; 62.6%) was significantly higher than that of women (n=1201; 37.4%; P<0.001). The causes of severe AKI were renal (n=1128; 35.1%), prerenal (n=642; 20%), obstructive (n=310; 9.6%) and in 12.7% of the patients-multifactorial. Overall, the most frequent cause of AKI was acute tubular necrosis (n=1069; 33.2%). The renal replacement therapy (RRT) was discontinued due to improved kidney function in 45.3% of cases. 8.1% of the patients remained dialysis dependent. The mortality rate was 44%.

CONCLUSIONS

During a 12-year period, the number of the patients with severe AKI increased three times with the predominance of men and elderly people. There was an observed increase in multifactorial causes of severe AKI; however, ATN remained dominant over the decade. The mortality rate remained high, almost half of the patients died, less than 10% remained dialysis dependent, the rest had the improvement of renal function.

Health status, renal function, and quality of life after multiorgan failure and acute kidney injury requiring renal replacement therapy

Background

Critically ill patients with acute kidney injury (AKI) in need of renal replacement therapy (RRT) may have a protracted and often incomplete rehabilitation. Their long-term outcome has rarely been investigated.

Study design

Survivors of the HANnover Dialysis OUTcome (HANDOUT) study were evaluated after 5 years for survival, health status, renal function, and quality of life (QoL). The HANDOUT study had examinded mortality and renal recovery of patients with AKI receiving either standard extendend or intensified dialysis after multi organ failure.

Results

One hundred fifty-six former HANDOUT participants were analyzed. In-hospital mortality was 56.4%. Five-year survival after AKI/RRT was 40.1% (86.5% if discharged from hospital). Main causes of death were cardiovascular complications and sepsis. A total of 19 survivors presented to the outpatient department of our clinic and had good renal recovery (mean estimated glomerular filtration rate 72.5±30 mL/min/1.73 m²; mean proteinuria 89±84 mg/d). One person required maintenance dialysis. Seventy-nine percent of the patients had a pathological kidney sonomorphology. The Charlson comorbidity score was 2.2±1.4 and adjusted for age 3.3±2.1 years. Numbers of comorbid conditions averaged 2.38±1.72 per patient (heart failure [52%] > chronic kidney disease/myocardial infarction [each 29%]). Median 36-item short form health survey (SF-36™) index was 0.657 (0.69 physical health/0.66 mental health). Quality-adjusted life-years after 5 years were 3.365.

Conclusion

Mortality after severe AKI is higher than short-term prospective studies show, and morbidity is significant. Kidney recovery as well as general health remains incomplete. Reduction of QoL is minor, and social rehabilitation is very good. Affectivity is heterogeneous, but most patients experience emotional well-being. In summary, AKI in critically ill patients leads to incomplete rehabilitation but acceptable QoL after 5 years.

Long-Term Mortality among Hospitalized Non-ICU Patients with Acute Kidney Injury Referred to Nephrology

BACKGROUND

Epidemiological studies of acute kidney injury (AKI) have focused on patients admitted to intensive care units (ICUs), and several have studied hospitalized non-ICU patients, but analysis of patients referred to Nephrology is sparse. We analyzed factors associated with short- and long-term morbimortality among hospitalized non-ICU patients with AKI who were referred to Nephrology.

METHODS

A retrospective study with data prospectively collected from 170 non-ICU patients, with referral to the Nephrology Unit, recruited over a 4-year period, was performed. AKI was classified according to the criteria based on risk, injury, failure, loss of kidney function and end-stage kidney disease (RIFLE). Risk factors that could influence prognosis of AKI and long-term mortality were analyzed at admission. Early on, 1- and 10-year mortalities were correlated with AKI RIFLE class, clinical and demographic characteristics.

RESULTS

Most patients were >65 years, with multiple comorbidities and frequent drug intake history. Median Charlson score was 6. Twenty-five percent of patients with previously unknown chronic kidney disease (CKD) were diagnosed with CKD during the study. Dialysis was required in 13.5% of patients. Hospital deaths were 22.4% and significantly associated with older age, RIFLE class L, higher peak serum creatinine, oliguria and decreased serum albumin levels. One-year (38.8%) and 10-year (68.8%) mortalities were significantly associated with age, prior cardiovascular disease, prior CKD and RIFLE class L. According to the Cox proportional hazard model, age, prior CKD and RIFLE class L were independent risk factors of death at 1 and 10 years.

CONCLUSIONS

AKI in hospitalized non-ICU patients is associated with high early and late mortality. This study increases our understanding of AKI among this specific population and can improve their management.

[Renal replacement therapy in the intensive care unit]

BACKGROUND

Acute kidney injury is still one of the most common serious complications in critical ill patients and is associated with high mortality. Even small changes in renal function significantly influence survival and long-term prognosis.

MATERIAL AND METHODS

Selective literature research and analysis of intensive care population with renal failure.

CONCLUSION

Prophylactic measures as well as early diagnosis and therapy must be the goal of a modern intensive care treatment. Various treatment modalities for renal replacement therapy allow individualized treatment of each patient. The review summarizes the main aspects on prophylaxis and early diagnosis of acute kidney injury as well as the different treatment modalities for an individualized renal replacement therapy.

Long-term outcomes of survivors of ICU acute kidney injury requiring renal replacement therapy: a 10-year prospective cohort study

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is associated with high in-hospital morbidity and mortality in critically ill patients. Long-term outcomes have received little attention.

METHODS

The aim of this study was to characterize AKI-chronic kidney disease (CKD) nexus in critically ill patients with AKI (RIFLE class F). We performed a single-centre prospective observational study of 425 consecutive critically ill patients with AKI requiring RRT. None of these patients had pre-existing kidney disease. Primary outcomes were vital status and renal function at hospital discharge and at 5 and 10 years of follow-up.

RESULTS

The overall in-hospital mortality of the study cohort was 47%, the mortality rates at 1, 5 and 10 years were 65, 75 and 80%, respectively. At hospital discharge, recovery of renal function was complete in 56% of survivors. None of these patients developed CKD during follow-up. Ninety percent of the 100 survivors with partial recovery of renal function had ongoing CKD during long-term follow-up. CKD progressed to end-stage renal disease (ESRD) in 12 patients (3% of the cohort or 5% of survivors). The patients with post-AKICKD had a higher prevalence of hypertension, a higher rate of fatal cardiac diseases and a higher all-cause death rate.

CONCLUSION

Long-term survival of critically ill patients with AKI requiring RRT is poor and determined by the development of de novo CKD. There is a need for close follow-up of patients surviving AKI to prevent progressive CKD and to reduce associated lethal cardiac events.

[Treatment of acute renal failure in Germany: Analysis of current practice]

BACKGROUND AND OBJECTIVES

There are currently no reliable data on the differential use of renal replacement therapy (RRT) options for critically ill patients with acute renal failure in Germany.

PATIENTS AND METHODS

A questionnaire-based survey was delivered to 2265 German intensive care units. The questionnaire contained 19 questions regarding RRT.

RESULTS

A total of 423 German intensive care units participated in the survey. The offered modalities of RRT varied significantly: the smaller the facility, the fewer different RRT options were available. Intermittent dialysis procedures were available in only 35% of hospitals with up to 400 beds. In university hospitals, hemodynamically unstable patients were exclusively treated by continuous RRT, whereas in hospitals with up to 400 beds, intermittent RRT was also used. In addition, treatment practice was also dependent on the specialization of the treating physicians: Isolated acute renal failure was treated more often intermittently by nephrologists compared to anesthesiologists (79.7 vs. 43.3%). Nephrologists also used extracorporeal RRT more often in cardiorenal syndrome (54.3 vs. 35.8%), whereas anesthesiologists preferred them in sepsis (37.3 vs. 23.1%). The choice of anticoagulant varied as well: Hospitals with up to 400 beds offered regional citrate anticoagulation in only 50% compared to 90% of university hospitals.

CONCLUSIONS

Currently, RRT treatment in acute renal failure on German intensive care units seems to be dependent on the size, local structures, and education of the intensivists rather than patient needs. Our results demonstrate the necessity to establish cross-disciplinary standards for the treatment of acute renal failure in German intensive care units.

Long-term prognosis after acute kidney injury (AKI): what is the role of baseline kidney function and recovery? A systematic review

OBJECTIVES

To summarise the evidence from studies of acute kidney injury (AKI) with regard to the effect of pre-AKI renal function and post-AKI renal function recovery on long-term mortality and renal outcomes, and to assess whether these factors should be taken into account in future prognostic studies.

DESIGN/SETTING

A systematic review of observational studies listed in Medline and EMBASE from 1990 to October 2012.

PARTICIPANTS

All AKI studies in adults with data on baseline kidney function to identify AKI; with outcomes either stratified by pre-AKI and/or post-AKI kidney function, or described by the timing of the outcomes.

OUTCOMES

Long-term mortality and worsening chronic kidney disease (CKD).

RESULTS

Of 7385 citations, few studies met inclusion criteria, reported baseline kidney function and stratified by pre-AKI or post-AKI function. For mortality outcomes, three studies compared patients by pre-AKI renal function and six by post-AKI function. For CKD outcomes, two studies compared patients by pre-AKI function and two by post-AKI function. The presence of CKD pre-AKI (compared with AKI alone) was associated with doubling of mortality and a fourfold to fivefold increase in CKD outcomes. Non-recovery of kidney function was associated with greater mortality and CKD outcomes in some studies, but findings were inconsistent varying with study design. Two studies also reported that risk of poor outcome reduced over time post-AKI. Meta-analysis was precluded by variations in definitions for AKI, CKD and recovery.

CONCLUSIONS

The long-term prognosis after AKI varies depending on cause and clinical setting, but it may also, in part, be explained by underlying pre-AKI and post-AKI renal function rather than the AKI episode itself. While carefully considered in clinical practice, few studies address these factors and with inconsistent study design. Future AKI studies should report pre-AKI and post-AKI function consistently as additional factors that may modify AKI prognosis.

Timing of acute kidney injury--does it matter? A single-centre experience from the United Kingdom

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) is associated with high mortality and long-term dependence on RRT. However, there is limited information about the difference in outcome between patients who develop AKI in the community (c-AKI), and those who develop AKI in hospital (h-AKI).

AIM

Identify differences in short- and long-term outcomes between patients admitted with c-AKI and h-AKI who require intermittent haemodialysis, and to identify factors that predict poor outcome.

DESIGN & METHODS

Single-centre, retrospective analysis of 306 patients with AKI who received intermittent haemodialysis between 2009 and 2011.

FOLLOW-UP

six months. Primary endpoints: patient and renal survival. Secondary endpoints: time on dialysis, length of hospital stay, and admission to the intensive care unit (ICU).

RESULTS

Survival for patients in the h-AKI group was significantly lower, at 42.9% (compared to 72%). They had a significantly longer length of stay. However, at 6-month follow-up, the survival benefit of the c-AKI group was no longer significant. Patients with h-AKI were more likely to be dialysis independent at discharge and six months although this result did not reach statistical significance. Independent predictors of survival to discharge within the entire group included: renal/post-renal causes of AKI, younger age, pre-existing diabetes, and c-AKI. The only independent predictor for RRT dependence at discharge and six months was pre-existing chronic kidney disease.

CONCLUSIONS

h-AKI is associated with high mortality and longer hospital stays during the acute admission. However, h-AKI patients who survive are more likely to be independent of RRT at discharge and follow-up.

Six-year single-center survey on AKI requiring renal replacement therapy: epidemiology and health care organization aspects

Evidence regarding hospital-based acute kidney injury (AKI) reveals a continuous increase in incidence over the years, at least in intensive care units (ICU). Fewer reports are available for non critically-ill patients admitted to general or specialist wards other than ICU (non-ICU). The consequence of greater incidence is an increase in therapies such as dialysis; but how the health care organization deals with this problem is not clearly known. Here we quantified the incidence of dialysis-requiring AKI (AKI-D) among patients admitted to a University Hospital which serves a population of 354,000 inhabitants. Between 2007 and 2012, the incidence of AKI-D increased from 209 to 410 per million population (pmp)/year; age of patients and cardiovascular comorbid pathologies also increased. AKI-D was more frequent in non-ICU and 32% of patients were admitted to ICU. Considering the site of treatment of non-ICU patients, in 2007 the ratio of patients admitted to non-ICU wards apart from Nephrology to those admitted to Nephrology was 1:1, but in 2012 the ratio increased to 2.4:1 (p < 0.05). The complexity of acute disease, measured with the New Simplified Acute Physiology Score (SAPS II), did not reveal differences over the years. The number of dialysis treatments/year increased by 82%, and the total hours/year increased by 86%. Low-efficiency daily dialysis was performed in 52.4% of patients admitted to ICU, but dialysis sessions longer than 8 h were performed in only 40% of cases. Overall, 6-year mortality was 48.8%, without significant differences over the years. Mortality in ICU was 65.6%, and in non-ICU 41.2% (p < 0.001). Dialysis treatments needed to be continued after hospital discharge in 21% of patients. We conclude that dialysis-requiring AKI is becoming more common, and that two-thirds of patients are admitted as non-ICU: in these patients, during the last year of the study, the treatment site was more frequently in non-ICUs other than Nephrology. Over the 6-year period, the local healthcare organization had to dispense 80% more dialysis treatments/year in terms of total number and hours of treatment. One-fifth of surviving patients needed to continue dialysis after hospital discharge. Our data highlight the public health importance of AKI and the need for adequate resources for Nephrology.

Chronic kidney disease rather than illness severity predicts medium- to long-term mortality and renal outcome after acute kidney injury

BACKGROUND

Acute kidney injury (AKI) requiring renal replacement therapy (RRT) continues to be associated with a hospital mortality of ∼50%. Longer-term outcomes have been less well studied. We sought to determine the influence of ventilation and of underlying chronic kidney disease (CKD) on medium and longterm mortality and renal outcomes.

METHODS

All patients requiring RRT for AKI in south west Scotland between 1 January 1994 and 31 December 2005 were followed prospectively. Survival of patients who were and were not ventilated and of those with and without underlying CKD was compared by odds ratio (OR), adjusting for age and sex. Renal outcomes were determined by interrogation of our biochemistry database.

RESULTS

Three hundred and ninety-six patients with AKI received RRT. One hundred and seventy-six (44%) were ventilated and 98 (25%) had underlying CKD. Patients who required ventilation had a significantly worse 90-day survival than those who did not (OR 2.10 for death; 95% CI 1.34, 3.29) whereas underlying CKD did not predict such an early adverse outcome (OR 1.49; 95% CI 0.89, 2.50). By 5 years, patients who had been ventilated during the acute illness were no longer at increased risk (OR 0.79; 95% CI 0.38, 1.62) whereas the adverse effect of underlying CKD was statistically significant (OR 6.05; 95% CI 2.23, 16.5). Underlying CKD was also a strong predictor of the need for RRT during follow-up.

CONCLUSION

In an unselected series of patients with AKI requiring RRT, underlying CKD rather than illness severity predicted medium- to long-term mortality.

Plasma inflammatory and apoptosis markers are associated with dialysis dependence and death among critically ill patients receiving renal replacement therapy

BACKGROUND

Survivors of critical illness complicated by acute kidney injury requiring renal replacement therapy (RRT) are at an increased risk of dialysis dependence and death but the mechanisms are unknown.

METHODS

In a multicenter, prospective, cohort study of 817 critically ill patients receiving RRT, we examined association between Day 1 plasma inflammatory [interleukin (IL)-1β, IL-6, IL-8, IL-10 and IL-18; macrophage migration inhibitory factor (MIF) and tumor necrosis factor]; apoptosis [tumor necrosis factor receptor (TNFR)-I and TNFR-II and death receptor (DR)-5]; and growth factor (granulocyte macrophage colony stimulating factor) biomarkers and renal recovery and mortality at Day 60. Renal recovery was defined as alive and RRT independent.

RESULTS

Of 817 participants, 36.5% were RRT independent and 50.8% died. After adjusting for differences in demographics, comorbid conditions; premorbid creatinine; nephrotoxins; sepsis; oliguria; mechanical ventilation; RRT dosing; and severity of illness, increased concentrations of plasma IL-8 and IL-18 and TNFR-I were independently associated with slower renal recovery [adjusted hazard ratio (AHR) range for all markers, 0.70-0.87]. Higher concentrations of IL-6, IL-8, IL-10 and IL-18; MIF; TNFR-I and DR-5 were associated with mortality (AHR range, 1.16-1.47). In an analysis of multiple markers simultaneously, increased IL-8 [AHR, 0.80, 95% confidence interval (95% CI) 0.70-0.91, P < 0.001] and TNFR-I (AHR, 0.63, 95% CI 0.50-0.79, P < 0.001) were associated with slower recovery, and increased IL-8 (AHR, 1.26, 95% CI 1.14-1.39, P < 0.001); MIF (AHR, 1.18, 95% CI 1.08-1.28, P < 0.001) and TNFR-I (AHR, 1.26, 95% CI 1.02-1.56, P < 0.03) were associated with mortality.

CONCLUSIONS

Elevated plasma concentrations of inflammatory and apoptosis biomarkers are associated with RRT dependence and death. Our data suggest that future interventions should investigate broad-spectrum immune-modulation to improve outcomes.

Long-term outcome of cats and dogs with acute kidney injury treated with intermittent hemodialysis: 135 cases (1997-2010)

OBJECTIVE

To determine the long-term outcome for small animal patients with acute kidney injury (AKI) treated with intermittent hemodialysis (IHD).

DESIGN

Retrospective case series.

ANIMALS

42 cats and 93 dogs treated with IHD for AKI.

PROCEDURES

Medical records of cats and dogs treated with IHD for AKI from January 1997 to October 2010 were reviewed. Standard methods of survival analysis with Kaplan-Meier product limit curves were used. The log-rank, Mann-Whitney, and Kruskal-Wallis tests were used to determine whether outcome, number of IHD treatments, or duration of hospitalization was different when dogs and cats were classified according to specific variables.

RESULTS

The overall survival rate at the time of hospital discharge was 50% (21/42) for cats and 53% (49/93) for dogs. The overall survival rate 30 days after hospital discharge was 48% (20/42) for cats and 42% (39/93) for dogs. The overall survival rate 365 days after hospital discharge was 38% (16/42) for cats and 33% (31/93) for dogs. For all-cause mortality, the median survival time was 7 days (95% confidence interval, 0 to 835 days) for cats and 9 days (95% confidence interval, 0 to 55 days) for dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Cats and dogs with AKI treated with IHD have survival rates similar to those of human patients. Although there was a high mortality rate prior to hospital discharge, those patients that survived to discharge had a high probability of long-term survival.

Risk factors and outcomes associated with acute kidney injury following ruptured abdominal aortic aneurysm

Background

Current data describing the epidemiology of acute kidney injury (AKI) following repair of ruptured abdominal aortic aneurysm (rAAA) are limited and long-term outcomes are largely unknown. Our objectives were to describe the incidence rate, risk factors, clinical course and long-term outcomes of AKI following rAAA repair.

Methods

Retrospective population-based cohort study of all referrals undergoing emergency repair of rAAA in Northern Alberta from January 1, 2002 to December 31 2009. Demographic, clinical, physiologic and laboratory data were extracted. AKI was defined and classified according to the AKIN criteria.

Results

In total, 140 patients survived to receive emergent rAAA repair. Post-operative AKI occurred in 75.7% of patients (n = 106), 78.3% (n = 83) of which occurred during the initial 24 hours of ICU admission. AKIN stage 1, 2, and 3 occurred in 47 (33.6%), 36 (25.7%) and 23 (16.4%), respectively, with 19 patients receiving renal replacement therapy (RRT). Several clinical and biochemical patient factors were associated with incident AKI, including baseline estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² (odds ratio [OR] 2.94; 95% CI, 1.15-7.51, p = 0.03), need for mechanical ventilation (OR 22.7; 95% CI, 7.0-72.1, p < 0.0001) and vasoactive therapy (OR 9.9; 95% CI, 3.0-32.2, p < 0.0001) and higher mean APACHE II scores (25.7 [8.2] vs. 16.3 [4.9], p < 0.0001). AKI was associated with a higher ICU (28.3% vs. 0%; p = 0.0008) and in-hospital case-fatality rate (35.9% vs. 0%, p = 0.0001). Of 102 survivors to discharge, 65.7% (n = 67) recovered to baseline kidney function. In multivariable analysis, greater severity of AKI (OR 5.01; 95% CI, 2.34-10.7, p < 0.001) and lower baseline eGFR (OR 0.96; 95% CI, 0.93-0.99, p = 0.03) were associated with non-recovery. AKI remained independently associated with 1-year mortality after adjusting for age, sex, comorbidity, and illness severity (OR 5.21; 95% CI, 1.04-26.2, p = 0.045; AUC 0.83; H-L GoF, p = 0.26). Among survivors at 1-year, only 63.4% (n = 55) had complete kidney recovery.

Conclusions

Following rAAA repair, AKI is a common complication independently associated with long-term post-operative mortality. A significant proportion of AKI sufferers in this setting fail to recover to baseline kidney function.

Choice of renal replacement therapy modality and dialysis dependence after acute kidney injury: a systematic review and meta-analysis

PURPOSE

Choice of renal replacement therapy (RRT) modality may affect renal recovery after acute kidney injury (AKI). We sought to compare the rate of dialysis dependence among severe AKI survivors according to the choice of initial renal replacement therapy (RRT) modality applied [continuous (CRRT) or intermittent (IRRT)].

METHODS

Systematic searches of peer-reviewed publications in MEDLINE and EMBASE were performed (last update July 2012). All studies published after 2000 reporting dialysis dependence among survivors from severe AKI requiring RRT were included. Data on follow-up duration, sex, age, chronic kidney disease, illness severity score, vasopressors, and mechanical ventilation were extracted when available. Results were pooled using a random-effects model.

RESULTS

We identified 23 studies: seven randomized controlled trials (RCTs) and 16 observational studies involving 472 and 3,499 survivors, respectively. Pooled analyses of RCTs showed no difference in the rate of dialysis dependence among survivors (relative risk, RR 1.15 [95 % confidence interval (CI) 0.78-1.68], I(2) = 0 %). However, pooled analyses of observational studies suggested a higher rate of dialysis dependence among survivors who initially received IRRT as compared with CRRT (RR 1.99 [95 % CI 1.53-2.59], I (2) = 42 %). These findings were consistent with adjusted analyses (performed in 7/16 studies), which found a higher rate of dialysis dependence in IRRT-treated patients [odds ratio (OR) 2.2-25 (5 studies)] or no difference (2 studies).

CONCLUSIONS

Among AKI survivors, initial treatment with IRRT might be associated with higher rates of dialysis dependence than CRRT. However, this finding largely relies on data from observational trials, potentially subject to allocation bias, hence further high-quality studies are necessary.

U-curve association between timing of renal replacement therapy initiation and in-hospital mortality in postoperative acute kidney injury

Background

Postoperative acute kidney injury (AKI) is associated with poor outcomes in surgical patients. This study aims to evaluate whether the timing of renal replacement therapy (RRT) initiation affects the in-hospital mortality of patients with postoperative AKI.

Methodology

This multicenter retrospective observational study, which was conducted in the intensive care units (ICUs) in a tertiary hospital (National Taiwan University Hospital) and its branch hospitals in Taiwan between January, 2002, and April, 2009, included adult patients with postoperative AKI who underwent RRT for predefined indications. The demographic data, comorbid diseases, types of surgery and RRT, and the indications for RRT were documented. Patients were categorized according to the period of time between the ICU admission and RRT initiation as the early (EG, ≦1 day), intermediate (IG, 2–3 days), and late (LG, ≧4 days) groups. The in-hospital mortality rate censored at 180 day was defined as the endpoint.

Results

Six hundred forty-eight patients (418 men, mean age 63.0±15.9 years) were enrolled, and 379 patients (58.5%) died during the hospitalization. Both the estimated probability of death and the in-hospital mortality rates of the three groups represented U-curves. According to the Cox proportional hazard method, LG (hazard ratio, 1.527; 95% confidence interval, 1.152–2.024; P = 0.003, compared with IG group), age (1.014; 1.006–1.021), diabetes (1.279; 1.022–1.601; P = 0.031), cirrhosis (2.147; 1.421–3.242), extracorporeal membrane oxygenation support (1.811; 1.391–2.359), initial neurological dysfunction (1.448; 1.107–1.894; P = 0.007), pre-RRT mean arterial pressure (0.988; 0.981–0.995), inotropic equivalent (1.006; 1.001–1.012; P = 0.013), APACHE II scores (1.055; 1.037–1.073), and sepsis (1.939; 1.536–2.449) were independent predictors of the in-hospital mortality (All P<0.001 except otherwise stated).

Conclusions

The current study found a U-curve association between the timing of the RRT initiation after the ICU admission and patients’ in-hospital mortalities, and alerts physicians of certain factors affecting the outcome after the RRT initiation.