Obesity, Renal Disease and the Impact of COVID-19

The National Kidney Foundation estimates that 37 million in the United States Have Chronic Kidney Disease (CKD), and 90 percent of them are unaware of their condition. Another roughly three-quarters of a million people have Acute Kidney Injury (AKI), of which 63 percent receive hemodialysis. Research increasingly identifies a relationship between the two, with CKD recognized as a risk factor for AKI, and AKI accelerating the progression of CKD. It is not surprise, then, that the National Kidney Foundation refers to CKD as an underrecognized public health crisis.

CKD is caused primarily by hypertension and diabetes, both common comorbidities for people with obesity, which itself is a risk factor. In fact, a high BMI is one of the strongest risk factors for new onset CKD, evidenced by a recent tenfold increase in obesity-related glomerulopathy. Among patients with CKD, a more rapid progression has been found in people with a BMI ≥ 35, and those with a larger waist circumference or waist-hip ratio may have decreased Glomerular Filtration Rate (GFR) or increased albuminuria, regardless of BMI. The relationship between obesity and renal issues is also found in patients with end stage renal disease and among those who have received transplants. These findings suggest that visceral adiposity plays a direct role in the disease even after the effects of comorbidities such as hypertension and diabetes have been mediated.

COVID-19 has created further complications, particularly for at-risk patients with chronic kidney disease who may have concerns about breaking quarantine for dialysis treatment. Hospitalized patients with CKD or coronavirus-related kidney injury are at higher risk for mortality than their healthier peers. The reason for this increase risk is unclear but is theorized to be the result of increased inflammation, enhanced immune response triggered by injury to the kidneys, or multiorgan failure. Initial data from New York, a hot spot in the early stages of the pandemic, supports these findings. Twenty to 40 percent of COVID-19 patients in their intensive care units developed kidney failure and required dialysis, and the mortality rate for kidney transplants reached as high as 30 percent.

Fortunately, CKD can be prevented and awareness is key. One reason that CKD remains underrecognized is because people often are symptom-free in the early stages of the disease. When symptoms do start, they may be attributed to other conditions, further delaying treatment. Because of the close link to diabetes and hypertension, patients with these diseases should be made aware of the risks to their kidney health, especially if they also have obesity. Educate patients on signs of kidney disease, such as reduced energy, trouble sleeping, cramping muscles, frequent urination or urine that is foamy or has visible blood. GFR and urine albumin testing should be closely monitored and decreases or increases, respectively, addressed pharmacologically and with lifestyle changes, including weight loss and exercise.

A 2019 article in Nephrology found that a Very Low Calorie Diet (VLCD) is a safe and beneficial option for those with CKD. Because of their unique dietary requirements, any type of weight loss for patients should be closely monitored to prevent potential complications, and modifications may be necessary to identify an appropriate balance of protein and carbohydrates to manage ketosis. As with all effective weight loss programs, exercise is also critical to maximize healthy outcomes and should be encouraged to reverse the effects of both obesity and CKD.