Kidney Function: Understanding Creatinine and eGFR

The Organs You Never Think About — Until They Start Failing

India has the fastest-growing rate of chronic kidney disease in the world. An estimated 17% of Indians have some degree of kidney dysfunction—most without knowing it, making a routine kidney function test critical for early detection.

You could lose 75% of your kidney function silently, without a single symptom. You'd feel completely fine. That's the problem with kidney disease: by the time symptoms appear, it's often past the point of reversal.

Years of poorly controlled diabetes or ignored high blood pressure can quietly destroy your kidneys while you "feel fine." This is why understanding creatinine, eGFR, and other kidney markers is critical — they reveal damage long before symptoms appear.

What Your Kidneys Actually Do

Your kidneys aren't just filters. They're sophisticated chemical processing plants that:

• Filter blood: 150 liters per day, producing about 1.5 liters of urine

• Remove waste: Creatinine, urea, toxins, drug metabolites

• Balance electrolytes: Sodium, potassium, calcium, phosphorus

• Regulate blood pressure: Through the renin-angiotensin system

• Produce hormones: Erythropoietin (for red blood cells), active vitamin D

• Maintain acid-base balance: Preventing metabolic acidosis

When kidneys fail, all of these functions are compromised. Toxins accumulate. Blood pressure rises. Anemia develops. Bones weaken. Electrolytes become dangerous.

India's Silent Kidney Crisis

The statistics are sobering:

• 17% of Indians have some form of chronic kidney disease (CKD)

• Over 200,000 Indians progress to end-stage kidney disease each year, according to data from the [Indian Journal of Nephrology]

• Only 10% of those who need dialysis actually receive it (cost and access barriers)

• Diabetes and hypertension cause 60-70% of kidney failure cases

• Average age of kidney failure in India: 10 years younger than in Western countries

India faces a kidney disease epidemic driven by the diabetes and hypertension epidemics.

Understanding Creatinine: The Number Everyone Watches

Creatinine is a waste product from muscle metabolism. Your kidneys filter it out. When kidney function declines, creatinine rises.

eGFR: The Number That Actually Matters

eGFR (estimated Glomerular Filtration Rate) tells you how many milliliters of blood your kidneys can filter per minute. It's calculated from creatinine, age, and sex.

Notice something important: you can lose 40% of kidney function (eGFR dropping from 100 to 60) while still being in "normal" creatinine range. This is why eGFR catches problems earlier.

The Warning Sign Most People Miss: Urine

Your urine tells a story. Here's what to watch for:

Protein in Urine (Albuminuria)

Healthy kidneys don't leak protein. When they're damaged, protein (especially albumin) spills into urine.

Microalbuminuria is a critical early warning. It appears years before creatinine rises. In diabetics and hypertensives, it's the canary in the coal mine.

Other Urine Changes to Notice

• Foamy urine: Suggests protein (like egg whites in a pan)

• Blood in urine: Could indicate kidney disease, stones, infection, or cancer

• Decreased output: Less than usual despite normal intake

• Getting up at night to urinate: Can indicate kidneys losing concentrating ability

The Causes: Why Kidneys Fail

The Big Two

Diabetes: The leading cause of kidney failure in India (and globally). High blood sugar damages the tiny blood vessels in kidney filtering units. Over 10-20 years, this leads to progressive loss.

Hypertension: The second leading cause. High pressure damages blood vessels throughout the kidneys. Uncontrolled BP + uncontrolled diabetes = accelerated kidney decline.

Other Important Causes

• Chronic glomerulonephritis: Inflammation of kidney filtering units

• Polycystic kidney disease: Genetic — kidneys develop multiple cysts

• Obstructive uropathy: Blocked urine flow (stones, enlarged prostate)

• Drug-induced: NSAIDs (painkillers), certain antibiotics, chemotherapy

• Recurrent kidney infections

• Unknown (idiopathic): ~10-15% of cases

Symptoms: The Late Arrivals

The tragedy of kidney disease is that symptoms appear only in advanced stages. Kidneys have so much reserve capacity that they compensate until 70-80% function is lost.

Early Stages (Often Nothing)

• No symptoms at all

• Maybe some fatigue (attributed to stress)

• Slightly elevated blood pressure

Moderate Stages

• Fatigue, weakness

• Swelling in feet and ankles (edema)

• Puffiness around eyes (especially morning)

• More frequent urination, especially at night

• Foamy urine

• Poor appetite, nausea

• Difficulty concentrating

Advanced Stages

• Severe fatigue, weakness

• Significant swelling

• Breathlessness (fluid accumulation)

• Persistent nausea, vomiting

• Muscle cramps

• Itching (uremic toxins)

• Sleep problems

• Mental confusion

The Tests Every Indian Should Know

Basic Kidney Panel

• Serum Creatinine + eGFR: The foundation

• Blood Urea/BUN: Another waste product, rises with kidney impairment

• Urine Albumin: Catches early damage

• Urine Routine: Checks for blood, protein, infection

Additional Tests When Abnormal

• Electrolytes: Sodium, potassium, calcium, phosphorus

• Hemoglobin: Anemia common in CKD (kidneys produce erythropoietin)

• Vitamin D: Often low (kidneys activate vitamin D)

• PTH (Parathyroid Hormone): Rises in CKD, affects bones

• Ultrasound: Checks kidney size, structure, obstruction

Who Should Be Screened

Protection: How to Save Your Kidneys

Control Diabetes Tightly

Keep HbA1c below 7%. Every point of HbA1c above target accelerates kidney damage. This is the single most important intervention for diabetic kidney protection.

Control Blood Pressure

Target below 130/80 if you have diabetes or kidney disease. ACE inhibitors or ARBs are preferred — they protect kidneys beyond just lowering BP.

Avoid Nephrotoxic Drugs

• Limit NSAIDs (ibuprofen, diclofenac, naproxen)

• Be cautious with certain antibiotics (aminoglycosides)

• Avoid herbal supplements with unknown ingredients

• Tell every doctor about your kidney status before they prescribe anything

Stay Hydrated (But Don't Overdo It)

Drink enough water to keep urine pale yellow. Dehydration stresses kidneys. But there's no need to force 8 glasses if you're not thirsty — overhydration isn't protective either.

Limit Protein (In Advanced CKD)

If eGFR is below 30, excessive protein can accelerate decline. Consult a renal dietitian.

Quit Smoking

Smoking directly damages kidney blood vessels and accelerates CKD progression.

When Kidneys Fail: The Options

If kidneys fail completely (Stage 5, eGFR below 15), there are three options:

1. Hemodialysis

Blood is filtered through a machine 3 times per week, 4 hours per session. Effective but demanding. Requires access creation (fistula or catheter). Most common option in India.

2. Peritoneal Dialysis

Done at home. Uses the abdominal lining as a filter. More freedom but requires training and discipline. Underutilized in India.

3. Kidney Transplant

The best option for suitable candidates. A living donor kidney lasts 15-20 years on average; a deceased donor kidney 10-15 years. Requires lifelong immunosuppression but offers the best quality of life.

The Drug That's Changing Everything: SGLT2 Inhibitors

A class of diabetes drugs — empagliflozin (Jardiance), dapagliflozin (Farxiga), canagliflozin (Invokana) — has been shown to dramatically slow kidney disease progression.

Originally developed for diabetes, these drugs protect kidneys even in non-diabetics with CKD. They've reduced progression to kidney failure by 30-40% in trials.

If you have diabetes and kidney disease, ask your doctor about these medications. They're game-changers.

Common Questions About Kidney Health

"Can kidney damage be reversed?"

In early stages (Stage 1-2), yes — especially if the cause is addressed (e.g., controlling diabetes and BP). In later stages, the goal is slowing progression, not reversal. But every bit of preserved function matters.

"My creatinine is normal but eGFR is 58. Should I worry?"

Mild reduction (60-89) may be normal in older adults or reflect a stable condition. But with diabetes, hypertension, or protein in urine, even an eGFR of 58 warrants close monitoring and protection strategies.

"How much water should I drink?"

Enough to produce pale yellow urine. For most people, 1.5-2 liters daily. Don't force excessive amounts — there's no evidence that extra water protects kidneys.

"Should I avoid protein?"

In early CKD, moderate protein is fine. In advanced CKD (Stage 4-5), protein restriction may help slow progression and reduce symptoms. Consult a kidney specialist.

"Can I take creatine supplements?"

Creatine can raise creatinine levels slightly (it's metabolized to creatinine), potentially confusing kidney function assessment. Avoid if you have CKD or if you're being monitored for kidney health.

The Importance of Early Detection

Mr. Sharma's story doesn't have a happy ending — not yet. His kidneys had been damaged too much by years of neglected diabetes and hypertension. He's now on dialysis, three times a week, hoping for a transplant.

But his son, who accompanied him that first day, got himself tested. At 32, with borderline diabetes and slightly elevated BP, his eGFR was normal. He was caught early. He's now on medication, lifestyle changes, and close monitoring.

He won't repeat his father's journey. That's the power of awareness and early action.

Track your kidney function over time with ExaHealth. Upload your lab reports and see your eGFR trends — because catching decline early can save your kidneys.