Incidence, risk factors and prognostic factors of acute renal failure in patients admitted to an intensive care unit

Association of Age, Frailty, and Strategy for Initiation of Renal-Replacement Therapy: A Post Hoc analysis of the STARRT-Acute Kidney Injury Trial

INTRODUCTION

This study was designed to assess the association of age and frailty with clinical outcomes in patients with severe acute kidney injury (AKI), according to accelerated and standard renal-replacement therapy (RRT) initiation strategies in the STARRT-AKI trial.

METHODS

This was a secondary analysis of an international randomized trial. Older age was defined as ≥65 years. Frailty was assessed using the clinical frailty scale (CFS) score and defined as a score ≥5. The primary outcome was all-cause mortality at 90 days. Secondary outcomes included RRT dependence and RRT-free days at 90 days. We used logistic and linear regression and interaction testing to explore the impact of age and frailty on clinical outcomes.

RESULTS

Of 2,927 patients randomized in the STARRT-AKI trial, 1,616 (55.2%) were aged ≥65 years (median [interquartile range] 73.9 [69.4-78.9]). Older patients had greater comorbid cardiovascular and chronic kidney disease, were more likely to be surgical admissions and to receive vasopressors at baseline. Older patients had higher 90-day mortality (50.4% vs. 35.6%, adjusted-odds ratio (OR), 1.81 [1.53-2.13], p < 0.001). There was no significant difference in RRT dependence at 90 days between older and younger patients (8.7% vs. 7.8%, adjusted-OR, 1.21 [0.82-1.79], p = 0.325). Patients with frailty had higher mortality; but no difference in RRT dependence at 90 days. There was no significant interaction between age and CFS score in relation to mortality, RRT dependence at 90 days, and other secondary outcomes. There was no significant difference in the proportion of patients who received RRT in the standard-strategy stratified by age groups (adjusted-OR, 0.85 [0.67-1.08], p = 0.180).

CONCLUSION

In this secondary analysis of the STARRT-AKI trial, older and frail patients had higher mortality at 90 days; however, there was no difference in RRT dependence. Mortality and RRT dependence were not modified by RRT initiation strategy in older or frail patients.

A nomogram for predicting 28-day mortality in elderly patients with acute kidney injury receiving continuous renal replacement therapy: a secondary analysis based on a retrospective cohort study

BACKGROUND

Acute kidney injury (AKI) is a common and serious condition, particularly among elderly patients. It is associated with high morbidity and mortality rates, further compounded by the need for continuous renal replacement therapy in severe cases. To improve clinical decision-making and patient management, there is a need for accurate prediction models that can identify patients at a high risk of mortality.

METHODS

Data were extracted from the Dryad Digital Repository. Multivariate analysis was performed using least absolute shrinkage and selection operator (LASSO) logistic regression analysis to identify independent risk factors and construct a predictive nomogram for mortality within 28 days after continuous renal replacement therapy in elderly patients with acute kidney injury. The discrimination of the model was evaluated in the validation cohort using the area under the receiver operating characteristic curve (AUC), and calibration was evaluated using a calibration curve. The clinical utility of the model was assessed using decision curve analysis (DCA).

RESULTS

A total of 606 participants were enrolled and randomly divided into two groups: a training cohort (n = 424) and a validation cohort (n = 182) in a 7:3 proportion. A risk prediction model was developed to identify independent predictors of 28-day mortality in elderly patients with AKI. The predictors included age, systolic blood pressure, creatinine, albumin, phosphorus, age-adjusted Charlson Comorbidity Index (CCI), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and sequential organ failure assessment (SOFA) score. These predictors were incorporated into a logistic model and presented in a user-friendly nomogram. In the validation cohort, the model demonstrated good predictive performance with an AUC of 0.799. The calibration curve showed that the model was well calibrated. Additionally, DCA revealed significant net benefits of the nomogram for clinical application.

CONCLUSION

The development of a nomogram for predicting 28-day mortality in elderly patients with AKI receiving continuous renal replacement therapy has the potential to improve prognostic accuracy and assist in clinical decision-making.

Medication use and hospital-acquired acute kidney injury: an electronic health record-based study

BACKGROUND AND AIMS

Medications remain an important contributor to the development of acute kidney injury (AKI). This study aimed to examine associations between (i) administration of medications known to reduce glomerular filtration rate (GFR), that is, GFR modifiers and subsequent hospital-acquired AKI; and (ii) potentially medication-related AKI and patient adverse outcomes.

METHODS

A retrospective cohort study utilising electronic health record data of patients admitted to a tertiary hospital in Australia in 2015. Timing of medication administration was compared with timing of AKI development. AKI cases were identified using an algorithm based on serum creatinine level changes. Multilevel regression models were applied with adjustment for relevant demographic and clinical factors.

RESULTS

Among 11 503 admissions, AKI was identified in 955 patients (8.3%) and 637 (66.7% of 955) were preceded by administration of a GFR modifier. Patients without prior AKI were 17% more likely to develop AKI after administration of these medications (adjusted odds ratio 1.17, 95% confidence interval (CI) 1.003-1.37). Older age and comorbidity with diabetes, acute myocardial infarction, peripheral vascular disease, liver cirrhosis and multiple myeloma were also significant predictors. Patients with potentially medication-related AKI were 11.69 times more likely to die in hospital (95% CI 7.84-17.43) and stayed 3.49 times longer in hospital (95% CI 3.26-3.73), compared with those without AKI.

CONCLUSIONS

Administration of medications contributing to the reduction of GFR is associated with an increased risk of hospital-acquired AKI and worse patient outcomes. Caution is required when prescribing these medications to patients at risk of developing AKI, and monitoring patients for deterioration is needed if administered.

Bleeding in Critically Ill Children-Review of Literature, Knowledge Gaps, and Suggestions for Future Investigation

Clinically significant bleeding complicates up to 20% of admissions to the intensive care unit in adults and is associated with severe physiologic derangements, requirement for significant interventions and worse outcome. There is a paucity of published data on bleeding in critically ill children. In this manuscript, we will provide an overview of the epidemiology and characteristics of bleeding in critically ill children, address the association between bleeding and clinical outcomes, describe the current definitions of bleeding and their respective limitations, and finally provide an overview of current knowledge gaps and suggested areas for future research.

Outcomes of hospital-acquired acute kidney injury in elderly patients: a single-centre study

BACKGROUND

HAAKI is a common clinical problem in hospitalized patients. Its incidence is high in older patients and carries worse prognosis. The presence of multiple co-morbidities, aging process, and frequent diagnostic and therapeutic interventions predispose elderly patients to HAAKI. This study aims to evaluate the spectrum, risk factors and determinants of outcome of elderly patients with HAAKI.

METHODS

This prospective study was conducted during January 2014 to September 2015 in the Department of nephrology, Institute of Medical Sciences, BHU, Varanasi, UP, India. First 100 HAAKI elderly (> 60 years) patients, who fulfilled the inclusion criteria were enrolled for study. HAAKI was defined as per RIFLE criteria after minimum 48 h of hospitalization. Clinical, biochemical, and radiological evaluation were done. Follow up was done till discharge or up to 30 days whichever was later.

RESULTS

Till selection and enrollment of first 100 HAAKI patients, total 23507 patients were hospitalized. 11.2% (n = 2635) patients were ≥ 60 years of age. Among 2635 elderly patients, 3.79% (n = 100) developed HAAKI. Commonest causes of HAAKI were sepsis (37%) followed by drugs like NSAID, Contrast agent, Amphotericin B, and antibiotics including amino glycosides in (24%) patents. DM and HTN were the commonest risk factors. Mortality was noted in 45% cases and rest 55% patients recovered with partial or full recovery of renal function. ICU admission, Oliguria, RIFLE-F, need of RRT, and SOFA score > 11 were independent determinants of outcome of elderly patients with HAAKI.

CONCLUSION

HAAKI is associated with increased morbidity and mortality in elderly patients. Associated co-morbid conditions predispose elderly patients to HAAKI. ICU admission, Oliguria, severity of renal failure, requirement of RRT, and initial SOFA score were strong predictors of survival of elderly patients with HAAKI.

Acute kidney injury in elderly patients: narrative review on incidence, risk factors, and mortality

Acute kidney injury (AKI) is characterized by a sudden renal dysfunction with consequent increase of nitrogenous products, hydroelectrolytic and acid–base disorders. Its prevalence is high in hospitalized populations (4.9%–7.2%), especially in intensive care units (ICUs). Despite all the technical and therapeutic advances that have occurred in the last few decades, the overall mortality of AKI patients remains high, reaching 80% in ICU patients. Several conditions predispose a patient to progress with AKI, including age, sepsis, surgeries, and comorbidities, such as systemic arterial hypertension, diabetes mellitus, heart disease, neoplasia, and chronic renal disease. Among these risk factors, age is emphasized, since, due to advances in the health area, there has been an increase in life expectancy, hence an increase in the demand of the elderly population for health services. At the same time, the elderly present a greater predisposition to the development of AKI, either due to kidney senility, or because of the high prevalence of comorbidities present, and medical interventions such as the use of contrasts and medications, which can also trigger AKI. Considering the relevance of the social role of the elderly and the scarcity of studies on AKI in the elderly admitted to the ICU, further studies are needed. This review article was elaborated considering the purpose: to assess incidence, risk factors, and mortality of AKI in elderly patients admitted to ICUs. Published studies were collected using the following inclusion criteria: be accessible in online databases (Lilacs, Scielo, and PubMed), have been published since 2000 and written in English, Portuguese, or Spanish. The descriptors used for the survey were “Acute Kidney Injury”, “Aging”, and “Elderly”. All items that did not fit in the above inclusion criteria were discarded. We have also presented a synthesis of the knowledge acquired during this review.

Drug therapy and other factors associated with the development of acute kidney injury in critically ill patients: a cross-sectional study

BACKGROUND

Acute kidney injury (AKI) is associated with a significant increase in morbidity, mortality, and health care costs. In intensive care units (ICU), AKI is commonly multifactorial and frequently involves diverse factors, such as hypovolemia, sepsis, and the use of nephrotoxic drugs. We aimed to investigate drug therapy and other factors associated with the development of AKI in a Brazilian public hospital.

METHODS

This is a cross-sectional study involving critically ill patients at an ICU of a tertiary hospital. All data on sequential serum creatinine (SCr) level, glomerular filtration rate (GFR), and urine output were collected during ICU stay. The primary outcome was the occurrence of AKI assessed by the Acute Kidney Injury Network (AKIN) criterion. Sociodemographics, clinical data and drug therapy were considered as covariates. Factors associated with AKI were assessed using logistic regression.

RESULTS

Overall, 122 participants were included in the study. Median age was 46.0 (interquartile range, IQ = 29.0-69.0) years, with a predominance of men (58.2%). Mean number of prescribed drugs throughout ICU stay was 22.0 ± 9.4. The number of potentially nephrotoxic drugs ranged from two to 24 per patient. A total of 29 (23.8%) ICU patients developed AKI. In the AKI-group, patients were older and showed higher Acute Physiology and Chronic Health Evaluation II (APACHE II) scores at admission, higher rates of sedation, mechanical ventilation, and infection. More drugs in general and specifically more vasoactive drugs were prescribed for AKI group. Patients who developed AKI tended to have extended stays in the ICU and a lower probability of being discharged alive than patients with no AKI development. Model adjustments of logistic regression showed that the number of medications (OR 1.15; 95% CI [1.05-1.27]) was the only factor associated with AKI in this study. This association was independent of drug nephrotoxicity.

DISCUSSION

Intensive care is characterized by its complexity that combines unstable patients, severe diseases, high density of medical interventions, and drug use. We found that typical risk factors for AKI showed statistical association on bivariate analysis. The contribution of drug therapy in the occurrence of AKI in medical ICUs reinforces the need for prevention strategies focused on early recognition of renal dysfunction and interventions in drug therapy. These actions would help improve the quality of patient care and ensure progress towards medication safety.

Acute kidney injury in critically ill patients with lung disease: kidney-lung crosstalk

Objective

To examine the factors associated with acute kidney injury and outcome in patients with lung disease.

Methods

A prospective study was conducted with 100 consecutive patients admitted to a respiratory intensive care unit in Fortaleza (CE), Brazil. The risk factors for acute kidney injury and mortality were investigated in a group of patients with lung diseases.

Results

The mean age of the study population was 57 years, and 50% were male. The incidence of acute kidney injury was higher in patients with PaO2/FiO₂<200 mmHg (54% versus 23.7%; p=0.02). Death was observed in 40 cases and the rate of mortality of the acute kidney injury group was higher (62.8% versus 27.6%; p=0.01). The independent factor that was found to be associated with acute kidney injury was PaO₂/FiO₂<200 mmHg (p=0.01), and the independent risk factors for death were PEEP at admission (OR: 3.6; 95%CI: 1.3-9.6; p=0.009) and need for hemodialysis (OR: 7.9; 95%CI: 2.2-28.3; p=0.001).

Conclusion

There was a higher mortality rate in the acute kidney injury group. Increased mortality was associated with mechanical ventilation, high PEEP, urea and need for dialysis. Further studies must be performed to better establish the relationship between kidney and lung injury and its impact on patient outcome.

Injurious mechanical ventilation causes kidney apoptosis and dysfunction during sepsis but not after intra-tracheal acid instillation: an experimental study

Background

Intratracheal aspiration and sepsis are leading causes of acute lung injury that frequently necessitate mechanical ventilation (MV), which may aggravate lung injury thereby potentially increasing the risk of acute kidney injury (AKI). We compared the effects of ventilation strategies and underlying conditions on the development of AKI.

Methods

Spraque Dawley rats were challenged by intratracheal acid instillation or 24 h of abdominal sepsis, followed by MV with a low tidal volume (LV_T) and 5 cm H₂O positive end-expiratory pressure (PEEP) or a high tidal volume (HV_T) and no PEEP, which is known to cause more lung injury after acid instillation than in sepsis. Rats were ventilated for 4 hrs and kidney function and plasma mediator levels were measured. Kidney injury was assessed by microscopy; apoptosis was quantified by TUNEL staining.

Results

During sepsis, but not after acid instillation, MV with HV_T caused more renal apoptosis than MV with LV_T. Increased plasma active plasminogen activator inhibitor-1 correlated to kidney apoptosis in the cortex and medulla. Increased apoptosis after HV_T ventilation during sepsis was associated with a 40% decrease in creatinine clearance.

Conclusions

AKI is more likely to develop after MV induced lung injury during an indirect (as in sepsis) than after a direct (as after intra-tracheal instillation) insult to the lungs, since it induces kidney apoptosis during sepsis but not after acid instillation, opposite to the lung injury it caused. Our findings thus suggest using protective ventilatory strategies in human sepsis, even in the absence of overt lung injury, to protect the kidney.

Clinical analysis of cause, treatment and prognosis in acute kidney injury patients

Acute kidney injury (AKI) is characterized by an abrupt decline in renal function, resulting in an inability to secrete waste products and maintain electrolyte and water balance, and is associated with high risks of morbidity and mortality. This study retrospectively analyzed clinical data, treatment, and prognosis of 271 hospitalized patients (172 males and 99 females) diagnosed with AKI from December, 2008 to December, 2011. In addition, this study explored the association between the cause of AKI and prognosis, severity and treatment of AKI. The severity of AKI was classified according to the Acute Kidney Injury Network (AKIN) criteria. Renal recovery was defined as a decrease in a serum creatinine level to the normal value. Prerenal, renal, and postrenal causes accounted for 36.5% (99 patients), 46.5% (126 patients) and 17.0% (46 patients), respectively, of the incidence of AKI. Conservative, surgical, and renal replacement treatments were given to 180 (66.4%), 30 (11.1%) and 61 patients (22.5%), respectively. The overall recovery rate was 21.0%, and the mortality rate was 19.6%. Levels of Cl⁻, Na⁺ and carbon dioxide combining power decreased with increasing severity of AKI. Cause and treatment were significantly associated with AKI prognosis. Likewise, the severity of AKI was significantly associated with cause, treatment and prognosis. Multivariate logistic regression analysis found that respiratory injury and multiple organ dysfunction syndrome (MODS) were associated with AKI patient death. Cause, treatment and AKIN stage are associated with the prognosis of AKI. Respiratory injury and MODS are prognostic factors for death of AKI patients.

Invasive mechanical ventilation as a risk factor for acute kidney injury in the critically ill: a systematic review and meta-analysis

Introduction

Mechanical ventilation (MV) is commonly regarded as a risk factor for acute kidney injury (AKI) in the critically ill. We investigated the strength of this association and whether settings of tidal volume (Vt) and positive end-expiratory pressure (PEEP) affect the risk for AKI.

Methods

We performed a systematic review and meta-analysis using studies found by searching MEDLINE, EMBASE, and references in relevant reviews and articles. We included studies reporting on a relation between the use of invasive MV and subsequent onset of AKI, or comparing higher with lower Vt or PEEP and subsequent onset of AKI. All studies clearly stating that MV was initiated after onset of AKI were excluded. We extracted the proportion with and without MV and AKI. We included 31 studies on invasive MV.

Results

The pooled odds ratio (OR) for the overall effect of MV on AKI was 3.16 (95% CI 2.32 to 4.28, P <0.001). Nearly all subgroups showed that MV increases the risk for AKI. The pooled OR for studies with a multivariate analysis including MV as a risk factor for AKI was 3.58 (95% CI 1.85 to 6.92; P <0.001). Different settings of Vt and PEEP showed no effect.

Conclusions

Invasive MV is associated with a threefold increase in the odds of developing AKI and various Vt or PEEP settings do not modify this risk. The latter argues in favour of a haemodynamic origin of AKI during MV.

Risk factors for development of acute kidney injury in critically ill patients: a systematic review and meta-analysis of observational studies

Background. Acute kidney injury (AKI) is a frequent complication of critically ill patients. The impact of different risk factors associated with this entity in the ICU setting is unknown. Objectives. The purpose of this research was to assess the risk factors associated with the development of AKI in critically ill patients by meta-analyses of observational studies. Data Extraction. Two reviewers independently and in duplicate used a standardized form to collect data from published reports. Authors were contacted for missing data. The Newcastle-Ottawa scale assessed study quality. Data Synthesis. Data from 31 diverse studies that enrolled 504,535 critically ill individuals from a wide variety of ICUs were included. Separate random-effects meta-analyses demonstrated a significantly increased risk of AKI with older age, diabetes, hypertension, higher baseline creatinine, heart failure, sepsis/systemic inflammatory response syndrome, use of nephrotoxic drugs, higher severity of disease scores, use of vasopressors/inotropes, high risk surgery, emergency surgery, use of intra-aortic balloon pump, and longer time in cardiopulmonary bypass pump. Conclusion. The best available evidence suggests an association of AKI with 13 different risk factors in subjects admitted to the ICU. Predictive models for identification of high risk individuals for developing AKI in all types of ICU are required.

The incidence and clinical features of acute kidney injury secondary to ureteral calculi

The aim of this study is to evaluate the incidence and clinical features of acute kidney injury (AKI) secondary to ureteral calculi. Between February 2002 and December 2009, the prevalence of AKI was 0.72% in our series of 2,073 cases of ureteral stones. The AKI patients received ureteroscopy or percutaneous nephrostomy as the primary treatment. The most popular symptom was significant decrease in urine output (75%, 12/16). Five cases (33.3%) were caused by bilateral ureteral stones, and 76.19% of the stones were located in the upper ureter, the mean size of single stone was 1.35 ± 0.38 cm. The serum creatinine before treatment was 514.34 ± 267.04 μmol/L and the blood urea nitrogen before treatment was 21.31 ± 10.24 mmol/L. 46.67% of the patients had a functional or anatomical solitary kidney unit. Our study suggests that risk factors for developing AKI in ureteral stone patients are bigger sized stones, ureteral stones in patients with only one functioning kidney or pre-existing kidney disease, and bilateral ureteral stones. Early effective drainage in these cases could decrease the risk developing AKI secondary to ureteral calculi.

Comparison between early and delayed acute kidney injury secondary to infectious disease in the intensive care unit

BACKGROUND

Results from a number of studies suggest that the delayed manifestation of acute kidney injury (AKI) is associated with higher in-hospital mortality, while other studies were unable to demonstrate any difference among early and delayed AKI in terms of in-hospital mortality.

OBJECTIVE

The aim of this study was to investigate differences in outcome among patients with AKI upon admission to an intensive care unit (ICU) and those who develop AKI post-admission.

METHODS

We studied patients with AKI secondary to infectious diseases admitted to the ICU. We retrospectively compared data on patients admitted with AKI (early AKI) with data on those who developed AKI 24 h after admission (delayed AKI).

RESULTS

Acute kidney injury occurred in 147 of 829 (17.7%) patients admitted to the ICU. Of these, 96 (65%) had early AKI and 51 (35%) had delayed AKI. Renal failure was classified according to RIFLE criteria-an AKI-specific severity score that is used to place patients into one of five categories: risk, injury, failure, loss or end-stage renal disease. Based on these criteria, 6% of the early AKI and 4% of the delayed AKI patients were in risk category, 18% of the early AKI and 27% of the delayed AKI patients were in the injury category and 76% of the early AKI and 69% of the delayed AKI patients were in the failure category. We found no significant association between RIFLE and death. On admission, patients with early AKI had statistically significantly higher serum urea and creatinine levels than delayed AKI patients (P<0.0001). Arterial bicarbonate was lower in early AKI (P=0.02). Sepsis, hypotension and use of mechanical ventilation were more frequent in delayed AKI (P<0.05). The APACHE II score was higher in early AKI (P=0.05) patients. In total, 98 (66.7%) patients died, with a tendency towards higher mortality in patients with delayed AKI (61.5 vs. 76.5%, P=0.07).

CONCLUSION

Mortality among patients with infectious diseases-associated AKI admitted to the ICU is high, with a trend to be higher in those who developed delayed AKI.

The kidney in the critically ill

Acute kidney injury (AKI) is a common and serious complication in the intensive care setting. It seldom occurs in isolation, but is mostly part of a multiple organ dysfunction syndrome. The pathogenesis is frequently multifactorial, with sepsis contributing to 50% of the cases.The development of AKI in critically-ill patients is "bad news": patients with AKI have a high morbidity and mortality. In addition, AKI, even in its mildest from, is not only a marker of illness severity but appears to be independently associated with mortality. Prevention of AKI is therefore a major goal to improve outcome of critically-ill patients. Treatment of established AKI is largely supportive. The optimal modality for renal replacement therapy in critically-ill patients still remains a matter of debate). The majority of survivors recover renal function.