The need for routine screening for chronic kidney disease in the elderly
Brian Bender, Ph.D.
Chronic kidney disease refers to the loss of renal function over time. As CKD develops, the kidney's ability to filter waste and fluid declines, potentially leading to the buildup of fluid, electrolytes, and waste that, if left unchecked, can lead to end-stage renal disease and the need for dialysis or a transplant.
CKD is a prevalent disease, affecting roughly 14% of the population. This devastating disease causes more deaths in the United States every year than prostate cancer and breast cancer. It's also costly, with global expenditures on CKD estimated to exceed $1 trillion.
Unfortunately, CKD often goes undiagnosed until serious complications arise from late-stage disease progression. Data from the NIH suggests over 90% of individuals with stage I-III CKD are not aware they have it.
The reason for the “silent” nature of this disease is that early-stage symptoms can be easily misdiagnosed. Symptoms such as nausea, fatigue, dizziness, and others are common and can be ignored or mistakenly associated with other illnesses the individual may have.
The elderly are high risk
Age is a major risk factor for CKD, and those over 65 years old should receive, at a minimum, annual screenings. One out of every 5 individuals in their 60s has CKD. Yet as we continue to age, the percentage of individuals over 70 with CKD climbs to over 45%.
Two leading risk factors for CKD include diabetes and hypertension. And as nearly two-thirds of elderly individuals have hypertension, the risk-pool is large.
Additionally, those with cardiovascular diseases (CVD), those that are obese, or those that smoke are at a greater risk of developing CKD. And certain ethnic groups, including African Americans, Hispanics, Asians, and American Indians are also at a greater risk.
It is important to diagnose early and monitor progressively.
Fortunately, diagnosing and monitoring CKD is relatively straightforward and can be performed non-invasively.
Urine, naturally, provides a window into the health of the kidneys. The primary method for assessing the health of the kidneys, as preferred by the National Kidney Foundation, is to perform a measurement of the urinary albumin to creatinine ratio. This ratio, collected from morning, spot urine samples, provides a quantitative assessment of how much blood albumin has leached into the urine, suggesting kidney damage.
In healthy individuals, albumin is not present in the urine. However, when concentrations rise to 30 mg/g of creatinine, kidney disease is potentially present. The National Kidney Foundation and The Kidney Disease: Improving Global Outcomes 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease require at least three tests over the course of at least three months with similarly high concentrations of urinary albumin to properly signify CKD.
Once CKD has been diagnosed, or even before, the quantitative assessment of UACR can help monitor disease progression. The National Kidney Foundation recommends testing routinely during regular checkups to assess disease progress in those at-risk. If UACR is rising, kidney function may be worsening.
Better to diagnose and monitor
It is imperative to diagnose CKD early in order to slow disease progression and prevent end-stage renal disease. ESRD leads to a significant decrease in quality of life and high risk of mortality. The number of ESRD prevalent cases continues to rise by about 21,000 cases per year.
It is also important to diagnose CKD early because CKD is associated with a high risk of morbitidy and mortality associated with CVD (such as atherosclerotic cardiovascular disease). In fact, UACR has been shown to be a good indicator of CVD and hypertension risk.
Other complications from CKD can arise as well. Those with CKD appear to be at a higher risk for dementia and other cognitive decline, and elderly individuals with CKD that have progressed to dialysis are more at risk for falls.
Lifestyle changes are important modifiers to help slow the progression of CKD. One of the more important changes relates to diet.
Kidneys play a vital role in the digestive process. Unsurprisingly, a decline in renal function affects the body's ability to excrete certain metabolites and regulate body fluids and electrolytes properly. Therefore, nutritional therapy becomes important for managing patients with CKD in order to prevent adverse health effects and slow the progression of kidney decline.
Protein is an important macronutrient to monitor in patients with CKD. Reducing protein intake has been shown to reduce the occurrence of renal death by 32%. Therefore, according to the KDIGO, it is important for individuals with CKD to reduce their protein intake. Specifically, the KDIGO recommends reducing protein intake to 0.8 grams per kilogram of body weight per day for individuals with or without diabetes and avoiding a high protein intake of over 1.3 grams/kg/day.
In addition, the KDIGO recommends reducing sodium intake to less than 2 grams per day. Potassium and phosphorus intake are additional minerals that need to be properly monitored and regulated, as malfunctioning of fluid filtering can cause electrolyte imbalances to build to dangerous levels.
These recommendations should be assessed in light of other health conditions. For example, sarcopenia is a concern during aging that can be remedied, in part, by maintaining adequate protein in the diet and potentially even increasing dietary protein intake. Complications such as this should be evaluated together with the caregiver to best manage comorbidities.
With early, regular screening, it is possible to greatly improve care of the elderly by properly diagnosing those with CKD and managing lifestyle factors such as diet and nutrition to prevent the onset of more serious, late-stage complications.
Brian Bender, Ph.D, is a certified nutritionist and biomedical engineer. He is a cofounder of Intake, a medical device company building sophisticated tools for diagnosing and monitoring personal health with a mission to improve preventative healthcare and combat chronic diseases.