By the bioMérieux Connection Editors
Acute kidney injury (AKI), an abrupt reduction in kidney function (usually occurring within 48 hours), is associated with short and long-term morbidity, increased mortality, and increased expenses for hospitals. While these effects are true for a variety of conditions, many studies have found that AKI is widely preventable, which means that the morbidity, mortality, and increased expenses are also avoidable. AKI impacts nearly 10% of hospitalized patients, and almost a third of these cases could likely be prevented.
In a 2015 ACP Hospitalist article, Andrew Fenves, MD, FACP, a nephrologist at Massachusetts General Hospital said, “Hospitalists in fact can do a lot of good things early in terms of the potential prevention of AKI, the early recognition of AKI, and the early adjustment of medications and dosing,” Dr. Fenves said. “Even those three things are important and potentially might avoid the need for us [nephrologists] to ever get involved.”
Potential Prevention of AKI
There are many factors that put a patient at higher risk of AKI, including age (65+), comorbid conditions (such as diabetes, heart failure, and chronic kidney disease), procedure-related factors (including surgeries, contrast-enhanced computed tomography, and significant blood loss), and acute conditions and medications (like sepsis, hypotension, and exposure to nephrotoxins). Identifying patients who present any combination of these risk factors is an important first step in preventing AKI.
After a patient is found to have a higher probability of developing AKI, there may be opportunities to lower this risk by modifying the nature of the upcoming procedure, altering the patient’s hemodynamic status, and providing alternate medications. An article written by nephrologists Mark D. Okusa and Kambiz Kalantari for Renal & Urology News recommends numerous preventive strategies to be considered when an individual at high risk for AKI is undergoing a procedure or being exposed to a nephrotoxic drug.
Early Recognition of AKI
After doing everything possible to mitigate an individual’s risk and potentially prevent AKI, it is imperative that the patient is monitored regularly for early recognition of AKI. There is an ongoing discussion on the methods used to quickly identify AKI—the traditional markers, blood area nitrogen (BUN) and serum creatinine (SCr), are understood to be the gold standard for the assessment of kidney function. The KDIGO Guidelines, a worldwide consensus documented by nephrologists, defines AKI as any of the following:
- Increase in SCr by ≥ 0.3 mg/dl (≥ 26.5 µmol/l) within 48 hours; or
- Increase in SCr to ≥ 1.5 times baseline, which is known or presumed to have occurred within the prior 7 days; or
- Urine volume <0.5 ml/kg/h for 6 hours
However, SCr does not reflect glomerular filtration rate (GFR) and will not rise until approximately 50% of kidney function is lost, indicating that it may not be the most effective detection method. Essentially, by the time the serum creatinine level rises significantly, kidney damage may have already occurred. There are a few alternative biomarkers currently being studied that have potential to be more sensitive than SCr, and clinicians are also investigating advanced analytic platforms to flag AKI before it occurs.
Optimized Treatment of AKI
AKI is can be reversible if it is detected and treated quickly; however, there is always the potential for lasting damage—for example, a recent report states that the presence of AKI can induce dysfunction of distant organs and that patients with AKI tend to have worse medium-term to long-term outcomes than other patients who did not develop AKI.
Once it has been ascertained that the patient has AKI, physicians should screen the patient’s medication list for potential nephrotoxicities and adjust the dosage of any new medications based on the reduced kidney function in an attempt to avoid further damage. A nephrologist can also be consulted, especially if renal replacement therapy, like dialysis, is being considered as a treatment option.
Treatment for AKI depends on the underlying cause of the kidney injury, which can include decreased blood flow to the kidneys, direct damage to the kidneys from sepsis or vasculitis, and blockage of the urinary tract. Generally, the goals of treatment are to preserve and enhance kidney function, maintain the body’s correct acid levels and electrolyte balance, and diminish secondary organ damage. Because there are no pharmacological treatments available for AKI, these goals must be accomplished through a focus on proper hydration, adequate monitoring of vital signs, and stabilizing the levels of minerals throughout the body.
Preventing AKI Can Save Lives
Morgan Grams, MD, PhD, of Johns Hopkins University School of Medicine, stated in an ACP Hospitalist article that, “AKI remains a frustrating complication for hospital physicians.” However, continued research and dedication towards prevention and early recognition of AKI can save lives. The National Institute for Health and Care Excellence in Ireland calculated that if AKI was recognized and treated with attention to hydration and medication, 100,000 cases could be prevented and up to 42,000 deaths avoided annually.
It is especially important to focus on prevention methods amid the COVID-19 pandemic—in previous reports of SARS and MERS-CoV infections, AKI developed in 5% to 15% of cases and carried an extremely high (60%-90%) mortality rate. There are still many unknowns about the SARS-CoV-2 virus, but keeping an eye on the aforementioned risk factors for AKI in COVID-19 infected patients is can help in early recognition.
Opinions expressed in this article are not necessarily those of bioMérieux, Inc.