Outcomes following dialysis for acute kidney injury among different stages of chronic kidney disease

Risk factors for major adverse kidney events in the first year after acute kidney injury

Background

Acute kidney injury (AKI) survivors are at increased risk of major adverse kidney events (MAKEs), including chronic kidney disease (CKD), end-stage kidney disease (ESKD) and death. High-risk AKI patients may benefit from specialist follow-up, but factors associated with increased risk have not been reported.

Methods

We conducted a retrospective study of AKI patients admitted to a single centre between 2012 and 2016 who had a baseline estimated glomerular filtration rate (eGFR) >30 mL/min/1.73 m² and were alive and independent of renal replacement therapy (RRT) at 30 days following discharge. AKI was identified using International Classification of Diseases, Tenth Revision codes and staged according to the Kidney Disease: Improving Global Outcomes criteria. Patients were excluded if they were kidney transplant recipients or if AKI was attributed to intrinsic kidney disease. We performed Cox regression models to examine MAKEs in the first year, defined as the composite of CKD (sustained 25% drop in eGFR), ESKD (requirement for chronic RRT or sustained eGFR <15 mL/min/1.73 m²) or death. We examined secondary outcomes (CKD, ESKD and death) using Cox and competing risk regression analyses.

Results

We studied 2101 patients (mean ± SD age 69 ± 15 years, baseline eGFR 72 ± 23 mL/min/1.73 m²). Of these, 767 patients (37%) developed at least one MAKE (429 patients developed CKD, 21 patients developed ESKD, 375 patients died). MAKEs occurred more frequently with older age [hazard ratio (HR) 1.16 per decade, 95% confidence interval (CI) 1.10–1.24], greater severity of AKI (Stage 2 HR 1.38, 95% CI 1.16–1.64; Stage 3 HR 1.62, 95% CI 1.31–2.01), higher serum creatinine at discharge (HR 1.04 per 10 µmol/L, 95% CI 1.03–1.06), chronic heart failure (HR 1.41, 95% CI 1.19–1.67), liver disease (HR 1.68, 95% CI 1.39–2.03) and malignancy (non-metastatic HR 1.44, 95% CI 1.14–1.82; metastatic HR 2.26, 95% CI 1.80–2.83). Traditional risk factors (e.g. diabetes and cardiovascular disease) had limited predictive value.

Conclusions

More than a third of AKI patients develop MAKEs within the first year. Clinical variables available at the time of discharge can help identify patients at increased risk of such events.

A nationwide survey of clinical characteristics, management, and outcomes of acute kidney injury (AKI) - patients with and without preexisting chronic kidney disease have different prognoses

Acute kidney injury (AKI) is a common complication in hospitalized patients. The International Society of Nephrology implemented the "0 by 25" initiative aimed at preventing deaths from treatable AKI worldwide by 2025 and conducted a global snapshot survey in 2014. We joined in the project and conducted this study to compare the epidemiology, risk factors, and prognosis between patients with pure AKI and those with acute-on-chronic kidney disease (ACKD). In this study, we prospectively collected demographic parameters and data on clinical characteristics, baseline comorbidities, management, and outcomes of 201 AKI patients in 18 hospitals in Taiwan from September 2014 to November 2014. The in-hospital mortality rate was 16%. AKI was mostly attributed to sepsis (52%). Multivariate logistic regression indicated that oliguria was a positive independent predictor of in-hospital mortality, whereas preexisting CKD and exposure to nephrotoxic agents were negative independent predictors. The prevalence of vasopressor use, intensive care unit care, and mortality were significantly higher in pure AKI patients than in ACKD patients. Moreover, serum creatinine (SCr) levels significantly increased within 7 days after AKI diagnosis in nonsurvivors but not in survivors in the pure AKI group. By contrast, SCr levels were persistently lower in nonsurvivors than in survivors in the ACKD group during the same period. We thus determined that the prognosis of ACKD patients differed from that of pure AKI patients. Considering the CKD history in the future AKI staging system may improve prognosis prediction.

Impact of weaning from acute dialytic therapy on outcomes of chronic kidney disease following urgent-start dialysis

Discontinuation of acute, unplanned dialysis is always an important therapeutic goal in dialysis-requiring patients with existing chronic kidney disease. Only a limited proportion of patients could be weaned off dialysis and remained dialysis-free. Here we performed a multicenter, observational study to investigate factors associated with successful weaning from acute dialysis, and to explore the potential impact of weaning itself on outcomes of patients with chronic kidney disease following urgent-start dialysis. We recruited 440 chronic kidney disease patients with a baseline estimated glomerular filtration rate <45 ml/min per 1/73 m2, and used propensity score-adjusted Cox regression analysis to measure the effect of weaning from acute dialysis on death during the index hospitalization and death or readmission after discharge. Over 2 years, 64 of 421 (15.2%) patients who survived >1 month died, and 36 (8.6%) were removed from dialysis, with 26 (6.2%) remaining alive and dialysis-free. Logistic regression analysis found that age ≧ 65 years, ischemic acute tubular necrosis, nephrotoxic exposure, urinary obstruction, and higher predialysis estimated glomerular filtration rate and serum hemoglobin were predictors of weaning off dialysis. After adjustment for propensity scores for dialysis weaning, Cox proportional hazards models showed successful weaning from dialysis (adjusted hazard ratio 0.06; 95% confidence interval 0.01 to 0.35), along with a history of hypertension and serum albumin, were independent protectors for early death. Conversely, a history of stroke, peripheral arterial disease and cancer predicted the occurrence of early mortality. In conclusion, this prospective cohort study shows that compared to patients with chronic kidney disease who became end-stage renal disease after acute dialysis, patients who could be weaned off acute dialytic therapy were associated with reduced risk of premature death over a 2-year observation period.

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.

Acute kidney injury in rats with or without pre-existing chronic kidney disease: cytokine/chemokine response

AIM

Evidence suggests the possibility that pre-existing chronic kidney (CKD) disease may result in a more severe outcome of acute kidney injury (AKI). The aim of this study was to examine whether CKD enhances the inflammatory response in the kidney, as well as other organs, in response to AKI in rats.

METHODS

CKD was induced by 5/6 nephrectomy (Nx) and AKI by intestinal ischaemia and reperfusion (IIR).

RESULTS

For 6 weeks following Nx there was a progressive increase in serum creatinine with associated development of albuminuria. The increment in creatinine above baseline determination 90 min following IIR was comparable in 5/6 Nx and in the sham 5/6 Nx. Similarly, increased levels of serum alanine transaminase and histomorphological changes in the lungs were observed in the rats exposed to IIR compared with those exposed to sham IIR, with no additional significant impact of 5/6 Nx. In kidney tissue the levels of cytokines/chemokines were equally elevated regardless of exposure to sham IIR or IIR. In lung and liver tissue the levels of cytokines/chemokines were equally elevated in the rats that were exposed to IIR, regardless of exposure to sham Nx or Nx.

CONCLUSION

We conclude that the immediate severity of AKI induced by IIR in rats with CKD is similar to that induced in rats without CKD. However, the impact of Nx on the cytokine/chemokine response after AKI is not uniform in kidney, lung or liver tissue.