The Silent Epidemic: Why 1 in 7 People Have Kidney Disease and Don't Know It
Part 1 of a 6-Part Series on Kidney Health and Longevity
What if I told you that right now, as you're reading this article, there's a 1 in 7 chance you have a disease that could be silently damaging your body, yet you have absolutely no idea?
I'm Dr. Sean Hashmi, a board-certified nephrologist and obesity medicine specialist, and I'm talking about chronic kidney disease—the condition affecting 35.5 million Americans that 90% of people don't even know they have.
Here's what's truly shocking: your kidney function, measured by something called eGFR (estimated glomerular filtration rate), is actually a better predictor of how long you'll live than many traditional heart health markers. Yet most people have never even heard of it.
The Staggering Global Impact
Let me paint you a picture of just how massive this problem really is:
8 to 16 percent of the global population is affected
673.7 million people worldwide are living with chronic kidney disease as of 2021
These numbers have nearly doubled since 1990
But here's the part that keeps me up at night as a nephrologist: less than 5 to 10 percent of people with kidney disease are aware they have it.
Think about that for a moment. We have nearly 700 million people walking around with a progressive disease that can lead to heart attacks, strokes, and kidney failure, and they have absolutely no idea.
Why We Call It the "Silent Epidemic"
The answer lies in how kidney disease works. Unlike a broken bone or a heart attack, early kidney disease doesn't hurt. Your kidneys are incredibly resilient—they can lose up to 50 percent of their function before you feel anything wrong.
It's like having a car where the engine warning light doesn't turn on until you've already lost most of your horsepower.
This is why we call it the "silent epidemic." It progresses without symptoms, without pain, without obvious warning signs, until it reaches advanced stages where treatment options become much more limited.
Who's at Highest Risk?
The statistics reveal concerning patterns everyone needs to understand:
Age Creates Vulnerability
34 percent of people over 65 have kidney disease
Only 6 percent of adults aged 18 to 44 are affected
This isn't just natural aging—it's accumulated damage from other conditions over time
Diabetes Creates Devastating Risk
1 in 3 adults with diabetes develops kidney disease
High blood sugar acts like sandpaper on kidney filters
Gradual wearing down occurs over years
Blood Pressure Becomes a Silent Destroyer
1 in 5 people with high blood pressure has kidney damage
High pressure forces blood through delicate vessels with damaging force
Causes scarring and damage over time
Racial Disparities Reveal Systemic Problems
Non-Hispanic Black adults have 4 times higher kidney failure risk versus White Americans
Hispanic Americans have twice the risk
Complex causes include genetics, healthcare access, socioeconomic factors, and higher diabetes/hypertension rates
These aren't just numbers—they represent millions of missed opportunities for early intervention. When we catch kidney disease early, we can often slow or even stop its progression.
Your Kidneys: Metabolic Powerhouses
Most people think kidneys just make urine, but that's like saying your smartphone just makes calls. Your kidneys are sophisticated, multi-tasking organs performing five critical functions every second of every day.
Function #1: Ultra-Sophisticated Filtration
Imagine the most advanced water purification system ever created, then multiply its complexity by a thousand.
The incredible filtration facts:
Filter approximately 180 liters of blood daily (enough to fill a standard bathtub)
Process your entire blood supply over 30 times each day
Work through structures called glomeruli
Think of glomeruli as incredibly selective "sophisticated bouncers" at an exclusive club. They let small waste products like urea and creatinine pass through into your urine, but they keep essential substances like proteins and red blood cells in your bloodstream where they belong.
When kidney disease develops, these "bouncers" become less selective, allowing valuable proteins to leak out while waste products build up.
Function #2: Blood Pressure Control Center
Your kidneys operate like having a "smart thermostat" for your circulation through something called the Renin-Angiotensin-Aldosterone System (RAAS).
How blood pressure control works:
When your blood pressure drops, specialized cells in your kidneys detect this change
They release an enzyme called renin
Renin converts a liver protein into angiotensin I
This becomes the powerful hormone angiotensin II in your lungs
Angiotensin II works like a master switch, constricting blood vessels and signaling adrenal glands to release aldosterone
Together, these actions raise blood pressure
In kidney disease, this system can malfunction, leading to high blood pressure that further damages the kidneys, creating a vicious cycle.
Function #3: Red Blood Cell Production Command
Here's something that surprises most people: your kidneys are actually hormone-producing glands.
The red blood cell production process:
Kidneys manufacture erythropoietin (EPO)—the same hormone athletes sometimes abuse for performance enhancement
EPO travels to bone marrow saying "We need more red blood cells"
Red blood cells are your body's "oxygen delivery trucks"
When kidney function declines, EPO production drops, leading to anemia. This is why fatigue is often one of the first symptoms people notice with kidney disease.
Function #4: Bone Health Guardian
Your kidneys perform a crucial step in vitamin D activation:
You get vitamin D from sunshine or supplements in inactive form
Kidneys convert it into calcitriol—the active form
Active vitamin D helps intestines absorb calcium
Keeps your bones strong and healthy
When kidney disease impairs this process, you can develop bone disease, mineral imbalances, and increased fracture risk.
Function #5: pH Balance Specialists
Your body's countless chemical reactions only work properly within a very narrow pH range—between 7.35 and 7.45. Think of this like the precise temperature needed for baking bread—too far off in either direction, and everything falls apart.
How kidneys maintain pH balance:
Remove excess acids from your blood
Regenerate bicarbonate, which acts as a buffer
When this fails, blood becomes too acidic (metabolic acidosis)
Results in worse bone disease, muscle breakdown, and accelerated kidney disease progression
The Tests That Could Save Your Life
Because early-stage kidney disease is so often silent, testing becomes absolutely critical. Fortunately, two simple tests can detect problems years before symptoms appear.
Test #1: Estimated Glomerular Filtration Rate (eGFR)
This blood test measures your creatinine level—a waste product from normal muscle activity. Using your creatinine along with your age and sex, we calculate your eGFR, which tells us how well your kidneys are filtering.
Think of eGFR as a "percentage of remaining kidney function":
Above 90: Normal kidney function (if no other damage signs)
60 to 89: Mild decrease (concerning if protein in urine present)
45 to 59: Moderate decrease (Stage 3a kidney disease)
30 to 44: Moderate to severe decrease (Stage 3b)
15 to 29: Severe decrease (Stage 4)
Below 15: Kidney failure (Stage 5)
Understanding your eGFR is like knowing your credit score—it gives you a clear number that represents your kidney health status and helps you track changes over time.
Test #2: Urine Albumin-to-Creatinine Ratio (UACR)
This simple urine test checks for albumin—a specific protein that shouldn't be in your urine in significant amounts.
Key UACR facts:
UACR of 30 mg/g or higher indicates kidney damage
Detects damage even if eGFR is still normal
Can detect problems 5 to 10 years before eGFR decline
Provides crucial intervention window
Think of UACR as an early warning system—like smoke detectors that alert you to fire before you see flames.
Why Both Tests Matter
These tests provide complementary information:
eGFR: Function—how well kidneys are working right now
UACR: Damage—whether kidney filters are becoming leaky
You can have early damage (abnormal UACR) with normal function (normal eGFR), especially in diabetes-related kidney disease. This is why both tests are essential for complete kidney health assessment.
Your Kidney Protection Action Plan
1. Get Tested Proactively
Don't wait for your doctor to suggest it
At your next appointment, specifically request both eGFR blood test and UACR urine test
Many people assume these are included in routine blood work—they often aren't unless you ask
2. Know Your Numbers
Learn your kidney numbers like you know blood pressure or cholesterol
Target goals: eGFR above 90, UACR below 30 mg/g
Write them down, track them over time
3. Track Trends, Not Just Single Values
Single test = snapshot
Number changes over time = real story
Stable numbers = good news
Declining trends = need immediate attention and intervention
4. Share This Knowledge
Tell three people about kidney disease awareness
Many at-risk people have never heard of these tests
You could literally save someone's life by encouraging screening
5. Address Risk Factors
Diabetes: Work with your doctor to manage blood sugar levels
High blood pressure: Take steps to control it
Lifestyle: Maintain healthy weight, eat a balanced diet, avoid smoking
Who Needs Testing?
Testing is essential for anyone with:
Diabetes
Hypertension
Heart disease
Obesity
Family history of kidney disease
If you fall into any high-risk categories, you should be getting both tests annually.
Key Takeaways
The Silent Crisis Reality
673.7 million people worldwide are affected, and 90% don't know it
Early stages are completely silent—no symptoms until advanced damage occurs
Your Kidneys Are Powerhouses
Five critical functions: filtration, blood pressure control (RAAS), red blood cell production (EPO), vitamin D activation, and pH balance
When these fail, cascading problems occur throughout your entire body
Life-Saving Tests Are Available
eGFR and UACR can detect problems 5 to 10 years before symptoms appear
They provide a precious intervention window
eGFR is the strongest predictor of overall longevity
What's Next?
In Part 2 of this series, we'll reveal what might shock you even more: your morning routine might be slowly destroying your kidneys, and you have absolutely no idea it's happening.
We'll cover:
"The Big Two Destroyers" causing over two-thirds of all cases
Complete hierarchy of kidney threats—ranked most to least dangerous
Which risk factors you control versus which you can't
The shocking reveal: Number 3 on our danger list will completely surprise you—something most people think is healthy
Your kidneys work tirelessly for you every second of every day—they deserve your attention and care.
Dr. Sean Hashmi, MD, MS, FASN, is a board-certified nephrologist and obesity medicine specialist passionate about empowering patients with evidence-based knowledge to take control of their health. For more kidney health resources, visit SELFPrinciple.org.
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