Chronic Kidney Disease
Ayman Al Jurdi, MD
Nephrology fellow, Massachusetts General Hospital and Brigham and Women's Hospital
Post-doctoral research fellow, MGH Center for Transplantation Sciences
Associate Editor, GlomCon Pubs
The kidneys are essential organs for survival in humans because they are involved in several important physiologic functions in the body. These functions include filtering and removal of toxins from the blood into the urine while holding and retaining important proteins in the blood, maintaining the balance of fluids in the body and regulation of blood pressure. As a result, people who have injury to their kidneys that results in persistently reduced functions can have issues with one or more of the above stated functions, including high blood pressure and accumulation of fluid and toxins.
Kidney disease usually manifests in one of two ways. It can manifest as a reduction in the kidney’s ability to filter toxins from the blood, a function called glomerular filtration, which is estimated using blood and urine tests, and expressed as an estimated glomerular filtration rate (eGFR). Another way kidney disease can manifest is through the presence of an increased amount of protein in the urine or proteinuria. While the kidney’s function is to filter toxins from the blood into the urine, the kidney’s filter is also supposed to retain important proteins in the blood and not lose them into the urine. Damage to the kidney’s filter, called the glomerulus, results in the kidney losing its ability to retain important proteins in the blood and hence their appearance in the urine. This is called proteinuria. The kidney disease improving global outcomes (KDIGO) guidelines defines chronic kidney disease as persistent abnormalities in kidney function (eGFR<60 ml/min/1.73 m2) or proteinuria (UACR>30mg/g) that persistent for at least three months.
Why should we care about chronic kidney disease?
Chronic kidney disease is very common. It affects 1 in 7 adults, 90 percent of whom do not even know they have chronic kidney disease. People with chronic kidney disease can develop symptoms that interfere with their quality of life, including shortness of breath, fatigue and leg swelling. Chronic kidney disease is also associated with a higher risk of cardiovascular disease, morbidity and mortality. When kidney disease becomes advanced, people may require treatment with a machine to replace the function of their non-functioning kidney. This treatment is called “dialysis”, which is life-sustaining for people with kidney failure but is associated with a significant reduction in their quality of life.
Can chronic kidney disease be prevented?
In many cases, yes! A large proportion of people who have chronic kidney disease develop it from uncontrolled diabetes, high blood pressure and in some cases obesity. Hence, important lifestyle choices to prevent chronic kidney disease include following a healthy diet, exercise and, in overweight or obese people, weight loss to target a normal weight. These can be effective preventive measures whether you already have diabetes and high blood pressure or not. In people who already have diabetes and high blood pressure, in addition to following the lifestyle changes discussed above, treatment with medications to control blood sugar levels and blood pressure can help prevent the development of chronic kidney disease.
Can chronic kidney disease be treated?
Yes! The goals of the treatment of chronic kidney disease include 1) slowing the progression of kidney disease, 2) controlling the symptoms, and 3) prevention of the development of cardiovascular disease and other complications of chronic kidney disease. The treatment of chronic kidney disease involves several aspects, including lifestyle changes and medications. First, it’s important to identify and treat the cause of the kidney disease. For example, controlling blood sugars for people who have kidney disease from diabetes is key in keeping their kidneys healthy. Second, controlling blood pressure aiming for a systolic blood pressure below 130 mmHg and a diastolic blood pressure below 80 mmHg can help slow the progression of chronic kidney disease. In this regard, medications from the classes called angiotensin-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) are most helpful, especially in people who have protein in the urine. There are also newer agents such as finerenone and SGLT2 inhibitors that have been shown to slow progression of chronic kidney disease, especially in people with diabetes. Lastly, restricting salt intake (less than 2 grams of sodium chloride per day), eating a less “acidic” diet (containing less red meat, more fruits and vegetables) and avoiding unnecessary medications that can hurt the kidney (such as non-steroidal anti-inflammatory drugs, or NSAIDs) can be helpful.
In summary, chronic kidney disease is common and is associated with reduced quality of life, higher risk of cardiovascular disease and higher risk of mortality. Efforts aimed at improving prevention and treatment strategies for chronic kidney disease are important to reduce the adverse health outcomes associated with chronic kidney disease.
References:
Centers for Disease Control and Prevention. Chronic Kidney Disease in the United States, 2021. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention; 2021.
Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group
KDIGO 2012 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney Int Suppl. 2013; 3: 1-150
Levey AS, de Jong PE, Coresh J, et al. The definition, classification, and prognosis of chronic kidney disease: a KDIGO Controversies Conference report. Kidney Int. 2011;80(1):17-28. doi:10.1038/ki.2010.483