Predictors of mortality in elderly patients with acute renal failure in a developing country

Drug-Induced Kidney Injury in the Elderly

The incidence of acute kidney injury in the elderly has grown over the past decade. One of the primary drivers is drug-induced nephrotoxicity, which is the result of a combination of the unique susceptibilities to kidney injury and the increased use of medications in the elderly population. Specific drug classes are associated with increased rates of kidney injury including agents that block the renin angiotensin system, antimicrobials, and chemotherapeutic agents. Mechanistically, injury may be due to hemodynamic effects, tubular or glomerular toxicity, and interstitial nephritis. Early recognition of nephrotoxicity is critical, as are preventative steps when applicable. Unfortunately, treatment for established drug-induced kidney injury is limited and supportive care is required. Limiting exposure to nephrotoxic drugs is critical in decreasing the incidence of acute kidney injury in the elderly patient.

Characteristics of and risk factors for death in elderly patients with acute kidney injury: a multicentre retrospective study in China

Purpose of the study

The incidence of acute kidney injury (AKI) with a poor prognosis in the elderly has been increasing each year. This study aimed to investigate the clinical characteristics of and risk factors for death from AKI in the elderly and help improve prognosis.

Study design

This study was a retrospective cohort study based on data from adult patients (≥18 years old) admitted to 15 hospitals in China between 1 January 2009 and 31 December 2011. The characteristics of AKI in the elderly were compared with those in younger patients.

Results

In elderly patients with AKI, rates of hypertension, cardiovascular disease and multiple organ dysfunction syndrome (MODS) were higher than in younger patients (44.2% vs 31.2%, 16.1% vs 4.6% and 20.9% vs 16.9%, respectively), the length of ICU stay was longer (3.8 days vs 2.7 days, P=0.019) and renal biopsy (1.0% vs 7.13%, P<0.001) and dialysis (9.6% vs 19.2%, P<0.001) were performed less. Hospital-acquired (HA) AKI was more common than community-acquired (CA) AKI (60.3% vs 39.7%), while the most common cause of AKI was pre-renal (53.5%). Multiple logistic regression analysis showed that age (OR 1.041, 95% CI 1.023 to 1.059), cardiovascular disease (OR 1.980, 95% CI 1.402 to 2.797), cancer (OR 2.302, 95% CI 1.654 to 3.203), MODS (OR 3.023, 95% CI 1.627 to 5.620) and mechanical ventilation (OR 2.408, 95% CI 1.187 to 4.887) were significant risk factors for death.

Conclusions

HA-AKI and pre-renal AKI were more common in the elderly. Age, cardiovascular disease, cancer, MODS and mechanical ventilation were independent risk factors for death in the elderly with AKI.

Epidemiology, outcomes and validation of RIFLE and AKIN criteria in acute kidney injury (AKI) in critically ill patients: Indian perspective

Although the epidemiology and the impact of Acute Kidney Injury on outcomes are well-known in the Western literature, good data is lacking from India. Most studies published from India have not evaluated epidemiology of Acute Kidney Injury in the Intensive Care Unit setting and/or have not used validated criteria. In our observational study of 250 patients, admitted to a tertiary level ICU, we have explored the epidemiology of Acute Kidney Injury using both RIFLE and AKIN criteria and have validated them. We have also demonstrated that the severity of AKI is an independent predictor of mortality in critically ill patients. Our results are very much comparable to other studies and we feel that this study will remain as an epidemiological reference point for Indian clinicians dealing with AKI.

The clinical features and outcome of crush patients with acute kidney injury after the Wenchuan earthquake: differences between elderly and younger adults

BACKGROUND

On May 12, 2008, a devastating earthquake hit Wenchuan county of China's Sichuan province. Acute kidney injury (AKI) is one of the most lethal but reversible complications of crush syndrome after an earthquake. However, little is known about the epidemiological features of elderly crush patients with AKI. The aim of the present study is to compare clinical features and outcome of crush related AKI between elderly and younger adults in the Wenchuan earthquake.

MATERIALS AND METHODS

A questionnaire was sent to 17 reference hospitals that treated the victims after the earthquake. Clinical and laboratory characteristics of crush patients with AKI were retrospectively analysed.

RESULTS

228 victims experienced crush related AKI, of which 211 were adults, including 45 elderly (age ≥ 65 years) and 166 younger adults (age, 15-64 years). Compared with the resident population, the percentage of patients was higher amongst elderly (19.7% versus 7.6%, P<0.001). The distribution of gender was similar in elderly and younger adults. Mean systolic blood pressure was higher in elderly groups. Although no statistical differences in number of injury and injury severity score were observed between elderly and younger adults, elderly victims had lower frequency of extremities crush injury; higher incidences of thoracic traumas, limb, rib, and vertebral fractures; lower serum creatinine, potassium and creatinine kinase levels; lower incidence of oliguria or anuria; lower dialysis requirement; underwent less fasciotomies and amputations, received less blood and plasma transfusions. Mortality were 17.8% and 10.2% in elderly and younger adults, respectively (P=0.165). Stratified analysis demonstrated the elderly receiving dialysis had higher mortality rate compared with younger patients (62.5% versus 10.5%, P<0.001). Multivariate logistic regression analysis indicated that need for dialysis and sepsis were independent risk factors for death in the elderly patients.

CONCLUSIONS

Elderly crush victims more frequently developed AKI in the Wenchuan earthquake, and they differ from younger adults in injury patterns and treatment modalities. The elderly patients with AKI requiring dialysis were at a relatively high risk of mortality.

Elderly patients with acute kidney injury (AKI): clinical features and risk factors for mortality

PURPOSE

Elderly patients with AKI are associated with considerable mortality. The clinical features and risk factors predicting poor outcomes of these patients are not known. The aim of this study is to investigate the clinical features and risk factors affecting mortality in elderly patients with AKI.

METHODS

A prospective study on the elderly patients with AKI (age ≥65 years old) was conducted. A consecutive sample of 99 elderly patients with AKI was evaluated. These patients were divided into survivor group and non-survivor group according their outcomes. Factors including clinical characteristics and laboratory features were compared between these two groups. Analysis of correlations between death and categorized risk factors was done by means of Pearson's chi-squared test (or Fisher's exact test). Multivariate logistic regression was performed to analyze the possible risk factors for death.

RESULTS

The main causes of the elderly patients with AKI were ischemia (53.34%), surgery (33.33%), sepsis/infection (10.10%), nephrotoxic drug (3.03%). The mortality rate of the elderly patients with AKI was 42%. Significant differences were found between the survival group and non-survival group of the elderly patients in concomitant disease, complicated with multiple organ dysfunction syndrome (MODS), albumin, etc. Concomitant disease and MODS were found to be the independent risk factors for death of the elderly patients with AKI after adjusting for age, sex, pre-albumin, sepsis/infection, and serum creatinine (SCr).

CONCLUSION

This study found that concomitant disease and MODS were the independent risk factors for the death of elderly patients with AKI.

In situ assembly, regeneration and plasmonic immunosensing of a Au nanorod monolayer in a closed-surface flow channel

Herein, a simple and effective approach is reported for the in situ generation and regeneration of a Au nanorod (AuNR) monolayer inside a glass/silica-based, closed-surface flow channel. The density of the AuNR monolayer in the flow channel can be easily modified by varying the concentration of the AuNR and the cetyltrimethylammonium bromide as well as the incubation time. The fabricated AuNR monolayer in the flow channels was stable under harsh conditions, such as in extreme pH, organic solvents and at a fast flow rate. In addition, the flow channel could be reused by removing the immobilized AuNRs via the injection of diluted aqua regia or potassium iodide; the AuNR monolayer can subsequently be regenerated. The AuNRs in the closed flow channel were further exploited as a label-free detection method for a clinical biomarker, neutrophil gelatinase-associated lipocalin (NGAL), based on single-nanoparticle plasmonic assay. The corresponding limit of detection for NGAL was measured to be 8.5 ng mL(-1) (~340 pM) based on a signal-to-noise ratio of 3. The estimated recovery of NGAL in human serum and urine was higher than 80%, which indicates that this technique could potentially be used for the diagnosis of acute kidney injury.

Acute kidney injury in the elderly population

The elderly population is more prone to acute kidney injury (AKI) than younger populations. Older patients have less renal reserve because of reduced glomerular filtration rates due to anatomic/functional changes, and concomitant diseases such as hypertension, diabetes, atherosclerosis, heart failure, ischemic renal disease, and obstructive uropathy. The risk of AKI may also increase as a result of aggressive diagnostic and therapeutic procedures, which include medical agents, radiology, and surgical intervention. AKI in the elderly has a multifactorial physiopathology due to different etiologies. Studies that have specifically compared prognosis of AKI in elderly versus young over the recent years suggest that age is a predictor of long-term outcome. In most cases, the treatment of AKI is similar for all age groups. The majority of critically ill patients with AKI will eventually need renal replacement therapy (RRT). The influence of RRT on renal outcome remains a subject of intense investigation and debate. Avoiding situations that could damage the kidney is an important strategy to prevent AKI development in the elderly, besides medical and interventional therapeutics.

NGAL: a biomarker of acute kidney injury and other systemic conditions

Neutrophil gelatinase-associated lipocalin (NGAL) is a 25 kDa protein belonging to the lipocalin superfamily. It was initially found in activated neutrophils, however, many other cells, like kidney tubular cells, may produce NGAL in response to various insults. Recently, it has been found to have a role in iron metabolism by virtue of its binding with siderophores. It has also been found to have a role in kidney development and tubular regeneration after injury. In experimental studies, it was found to be highly expressed in response to tubular injury. In subsequent clinical studies, urine NGAL has been found to be an early predictor for acute kidney injury (AKI). Newer devices for early bedside detection of NGAL are now available. Since serum creatinine is known to be an inadequate and late marker of AKI, NGAL might soon emerge as a troponin-like early marker for AKI. Recent evidence also suggests its role as a biomarker in a variety of other renal and non-renal conditions.

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.