Post Date December, 03 2023
Definition and classification of acute and chronic kidney diseases
In 2002, KDOQI released a guideline for chronic kidney disease (CKD). The definition is an estimated decrease in glomerular filtration rate (eGFR) and proteinuria for at least 3 months. Classification is mainly based on eGFR. Subsequently published guidelines revised the classification method to include two factors, proteinuria and etiology.
In 2014, the Acute Dialysis Quality Initiative (ADQI) proposed the RIFLE diagnostic criteria for acute renal injury (AKI), which are classified as risk of renal injury, renal injury, renal failure, renal function loss, and end-stage renal failure. Thereafter, the standard was redefined as Phase 3. This has been revised in the 2012 KDIGO Clinical Practice Guidelines.
The current definition and classification of AKI only includes functional changes: changes in blood creatinine and urine volume, while the definition of CKD includes changes in structure (proteinuria) and function (eGFR).
Initial reaction
The international kidney organization KDOQI believes that the proposal of AKD may cause confusion for clinicians, leading to the neglect of other important clues in diagnosis. Moreover, there are many different types of AKD, and it is difficult for clinicians to distinguish its etiology. KDOQI recommends in-depth research into the possible causes of AKD diagnosis. At the same time, it is believed that this standard is more suitable for epidemiological investigation than for clinical use.
The Canadian Society of Nephrology (CSN) also emphasizes that although it is important to classify all kidney diseases, the clinical application of the AKD standard is not clear. It supports the application of the concept of AKD to epidemiological research, but clinical application should be cautious to prevent clinicians from neglecting to investigate the cause in depth and missing timely treatment.
Research on Application of AKD Standard
Chu et al. in China have conducted the only research that currently applies the AKD standard. All patients underwent renal biopsies, ruling out cases of significant fibrosis or sclerosis. They were divided into three groups: AKI, AKD without AKI, and AKD without AKI.
Patients who meet the AKD diagnosis have higher Scr levels during biopsy. AKI patients have the highest levels of Scr, are most likely to require renal replacement therapy, have the longest hospital stay, and are more expensive. AKI patients had the worst renal function during hospitalization.
There were differences in renal biopsy results among the three groups. Acute tubular necrosis in the AKI group was twice as high as in the AKD group without AKI (30.8%: 16.0%). In acute interstitial nephritis, there were more AKD patients without AKI than AKI patients (52.0%: 30.8%). The two groups of crescentic glomerulonephritis were similar (28.8%: 29.3%), with few thrombotic microangiopathy and composite injuries.
This indicates that patients who meet AKD have different etiologies. However, because all the patients in the study underwent renal biopsy, it cannot represent all AKD patients.
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Future direction
In order to better apply AKD in clinical practice, further research is needed to remedy current knowledge gaps, including the following:
Diagnosis of AKD: Characteristics of AKD in different environments (including hospitals, communities, and emergency departments), including cases that do not meet AKI or CKD.
AKD management: How to treat and care patients who meet AKD standards, including how to study and manage AKD or CKD without AKI in clinical practice.
Prognosis of AKD: Population based studies are needed to study the incidence and progression of major outcomes such as CKD, end-stage renal disease, and mortality.
The relationship between AKD, CKD, and AKI: Focus more on the characteristic changes that AKD progresses to CKD, rather than focusing solely on the cure or restoration of normal renal function by AKD, including better understanding of the impact of changes in renal disease indicators.
Clinical Impact of Case Discovery: Studying the complications of AKD and the costs of case discovery and clinical monitoring, including exploring the impact of applying the definition of AKD to case discovery and referral.
Applying a classification system and nursing model that includes CKD and AKD: determining whether education, diffusion, and implementation of AKD standards, as well as nursing models that include acute and chronic kidney disease, can improve short-term and long-term clinical outcomes.
