This new review article considers evidence that acute and chronic kidney diseases are not distinct entities but rather are closely interconnected. The implications of this insight are discussed in terms of the approach to patients with kidney disease.
During the past decade, separate conceptual models for chronic kidney disease and acute kidney injury were developed to facilitate organized approaches to clinical research and trials. Recent epidemiologic and mechanistic studies suggest that the two syndromes are not distinct entities but rather are closely interconnected — chronic kidney disease is a risk factor for acute kidney injury, acute kidney injury is a risk factor for the development of chronic kidney disease, and both acute kidney injury and chronic kidney disease are risk factors for cardiovascular disease.
Multiple risk factors for acute kidney injury are now known to include advanced age, diabetes mellitus, and black race. Similar risk factors have been identified for chronic kidney disease. However, the most important risk factor for acute kidney injury is preexisting chronic kidney disease, which increases risk by as much as 10 times, as compared with the absence of chronic kidney disease.
Several findings suggest that acute kidney injury not only is directly linked to the progression of chronic kidney disease but causes chronic kidney disease as well. First, the increased severity of acute kidney injury is associated with the development of chronic kidney disease. Second, multiple episodes of acute kidney injury predict the development of chronic kidney disease.
Morning Report Questions
Q: What is the association between acute kidney injury or chronic kidney disease and cardiovascular disease?
A: In addition to being associated with chronic kidney disease, acute kidney injury is linked to the development and treatment of cardiovascular disease. A strong association between chronic kidney disease and an increased risk of cardiovascular events is well documented. Patients who survive an episode of acute kidney injury are also at risk for major adverse cardiovascular events, as well as for progression to chronic kidney disease, regardless of whether there is underlying cardiovascular disease. Patients with acute kidney injury after coronary angiography are at risk for hospitalization for cardiovascular causes, myocardial infarction, and vessel reocclusion; the severity of acute kidney injury has been associated with hospitalization for heart failure. Acute kidney injury is associated with higher rates of death or subsequent hospitalization for stroke, heart failure, or myocardial infarction than the rates associated with previous myocardial infarction.
Q: What are strategies for management after an episode of acute kidney injury?
A: Patients with acute kidney injury should have periodic assessment of renal function and the urinary albumin-to-creatinine ratio to assess prognosis and outcome after discharge. The appropriate treatment for patients who survive an episode of acute kidney injury, regardless of whether they have chronic kidney disease, is unclear. Reasonable therapeutic approaches to patients who do not have preexisting kidney disease but do have evidence of renal injury include, first, “do no harm,” by avoiding nephrotoxic medications, including nonsteroidal antiinflammatory drugs and radiocontrast agents. In addition, one needs to determine the appropriate treatment for important risk factors for chronic kidney disease such as diabetes and hypertension. The preventive use of inhibitors of the renin-angiotensin-aldosterone system, low-sodium diets, or both should be evaluated in such patients. The authors note that it is not known whether these therapeutic approaches ameliorate or worsen outcomes in patients with acute kidney injury or in those with combinations of acute kidney injury and chronic kidney disease. Patients who have had acute-on-chronic episodes of acute kidney injury and chronic kidney disease should be followed by primary care physicians as well as nephrologists to ensure the highest standards of care.