What Is Chronic Kidney Disease? — Lamps Going Out One by One, and the Load on Those Still Lit

A Single Line on the Report

As you flip through your health checkup results, you notice a small mark next to a line of blood test data. You feel no pain. You urinate as usual, and your body is not swollen. People with the disease this article will cover often have no symptoms at all, and even when they do, the signs are vague—such as fatigue, itching, or loss of appetite—which commonly arise from other causes (PMID 27887750). Diagnosis often happens by chance through routine urine or blood tests during a checkup, or only after symptoms become severe (PMID 27887750).

The kidneys are a pair of kidney bean-shaped organs located in the upper back on either side, filtering the blood to send waste and excess water out as urine. In Korean, they are called sinjang in Sino-Korean vocabulary, but this article will use the native Korean word kongpat.

Chronic kidney disease is a condition where damage to the kidneys or a decline in kidney function lasts for three months or longer. This article looks in turn at what numbers define this disease, why it gradually progresses once it begins, what causes it, why so many people are unaware of it, and what slows its progression. The evidence is based on global research, while how common this disease is in Korea and how well-known it is are examined using data from the Korea National Health and Nutrition Examination Survey conducted by the South Korean government.

The Tiny Filtering Units Inside the Kidneys

The kidneys filter blood through tiny, shared units. A nephron is the smallest functional unit of the kidney that filters blood to produce urine, consisting of a filtering component and a tiny tubule through which the filtered fluid flows. The glomerulus is a cluster of tiny blood vessels at the very front of the nephron that filters water and small substances from the blood. How the kidneys filter blood is followed from the beginning in "How Do the Kidneys Filter Blood? — A Sieve That Takes Almost Everything Back".

There are two scales that define this disease. One is how much the kidneys filter. The glomerular filtration rate is the amount of water in the blood filtered by the kidney's glomeruli per minute, representing the primary number that indicates how well the kidneys are working. The glomerular filtration rate is the indicator that best reflects overall kidney function, measured directly through the clearance of a special substance introduced into the body or estimated through a formula (PMID 27887750).

Creatinine is a waste product produced mainly by muscles, and because the kidneys filter it out, its concentration in the blood is used to gauge kidney function. The eGFR is an estimated glomerular filtration rate calculated by plugging information like age and sex into a formula along with blood creatinine levels. It is also called the estimated glomerular filtration rate, and formulas include those that use only creatinine as well as those that use other blood test values together (PMID 37787795).

The other is the sign of kidney damage. Albumin is a protein produced by the liver and released into the blood, making up the largest portion of proteins in the blood of a healthy person. The glomeruli keep out most of these large proteins. Albuminuria is when albumin, a protein that should not be filtered out, leaks into the urine in amounts greater than normal.

Current international guidelines define chronic kidney disease, regardless of cause, as a glomerular filtration rate that has fallen below 60, markers of kidney damage, or both persisting for three months or longer (PMID 27887750). 60 is the number of milliliters filtered per minute, adjusted for body size. Albuminuria is a primary marker of damage, using a threshold of 30 milligrams or more based on the amount excreted in urine over a day (PMID 31573641). The units written on test strips may differ, and how to read those numbers is followed in "Reading Your Kidney Test Results — A Sieve You Cannot See, What Stays Behind and What Leaks Through". The definition also includes the condition that the abnormality affects health (PMID 39885176).

The line is one drawn by guidelines. A 2012 analysis supported the cutoff of 60 while also suggesting that the 60–74 range may represent an early stage of this disease, and noted that this conclusion needs to be reconfirmed with calculation formulas less skewed in the normal range (PMID 22038337). There is also a question from the opposite side. Studies are mixed on how much a number falling below 60 with age, in the absence of albuminuria, increases risk, and that question is picked up by "How Do the Kidneys Filter Blood? — A Sieve That Takes Almost Everything Back". Because the weight of the same number can differ depending on age and albuminuria, how to interpret numbers near the cutoff remains under debate.

The three-month condition is a line drawn by time. Kidney abnormalities lasting three months or less are grouped separately under acute terms, and a sudden decline in kidney function within days is one branch within that group (PMID 34252450). The differences between the two acute names and what follows are tracked in "What Is Acute Kidney Injury? — A Tap That Suddenly Runs Dry, and Three Places to Look".

Chronic kidney disease is a state where filtering power has decreased or things that should not leak are leaking, persisting for three months or longer, and is detected and staged through simple blood and urine tests (PMID 41314225).

Lamps That Go Out One by One

Chronic kidney disease usually worsens slowly, and the nephrons lost along the way do not return (PMID 32060481). Along the path of decline, regardless of the cause, there is one common link that appears. When nephrons are lost irreversibly, a heavier burden of blood flow and metabolism is placed on the remaining nephrons, and that burden causes more nephrons to be lost in turn (PMID 39885176).

If you picture the kidneys as a string of countless lamps with each compartment lit one by one, it looks like this. Compartments that go out do not light up again. The share of the work done by the extinguished compartments falls upon the ones that remain, and the compartments that carry the extra load eventually go out as well. This loop works together to make the disease go out compartment by compartment.

The analogy holds true only up to this single loop. In actual kidneys, the loss of cells goes hand in hand with long-standing inflammation, the accumulation of scars known as fibrosis, and a diminishing capacity for recovery, all of which contribute to the progression (PMID 32060481). Chronic kidney disease in adults can stem from a single cause, but it frequently results from multiple injuries accumulated over a lifetime or from co-existing risk factors (PMID 39885176), and the speed at which the lamps go out varies from person to person.

This disease has no curative treatment, and it progresses as time passes (PMID 34175022). Current treatments have limited efficacy and only slow down the progression, while methods to halt or reverse the progression are still under research (PMID 32060481). Methods to lighten the load on the remaining compartments and slow down the rate at which they go out will be examined in later sections.

Lost nephrons do not return, and the burden placed on the remaining nephrons causes more nephrons to be lost in turn.

Two Scales — The Stages

The international kidney disease guideline organization (KDIGO) proposed both a definition for this disease and a staging system that runs from the stage where function is preserved despite injury all the way to kidney failure (PMID 15880190). The stages of chronic kidney disease are divided into boxes numbered 1 through 5 based on the glomerular filtration rate, and the larger the box number, the less filtering power the kidneys have left. Stages 1 and 2 are cases where the glomerular filtration rate is still high, above 90 and between 60 and 89 respectively, but albuminuria is present, while stage 3 is 30 to 59, stage 4 is 15 to 29, and stage 5 is below 15 (PMID 27383068).

Kidney failure is a state where kidney function has dropped so severely that the kidneys alone can no longer handle the body's waste products and excess water. In chronic kidney disease, the heaviest stage 5 corresponds to this, and it is also called end-stage kidney disease. It is estimated that roughly 4 million people worldwide need dialysis or transplantation due to kidney failure (PMID 41314225). In places where dialysis or transplantation cannot be received, kidney failure is a fatal disease, and many regions of the world are in that situation (PMID 39885176).

Which path to choose in kidney failure differs depending on each person's circumstances. Dialysis, transplantation, and a path that cares for the body comfortably without dialysis are all options, and "Dialysis and Kidney Transplantation — Three Sieves That Stand In, and the Path That Uses None" accompanies this.

The second scale is the amount of albumin leaking into the urine. Staging and risk assessment that use both the glomerular filtration rate and albuminuria help determine treatment, test intervals, and whether to refer to a specialist (PMID 31573641). The two numbers tell us different things. Glomerular filtration rate and albuminuria were each independently associated with death and kidney failure, and these results were similar across populations in North America, Asia, Oceania, and Europe (PMID 22038337).

In an analysis pooling observational data from 114 cohorts involving roughly 27,50만 [sic] people, the lower the glomerular filtration rate and the more urinary albumin there was, the more all 10 adverse outcomes—including kidney failure, death, heart failure, stroke, and hospitalization—occurred, and that was true even in the mildest box of this disease (PMID 37787795). Because this is an observational study, this is an association of things appearing together. However, even the mildest box was not excluded from this association.

One review notes that people at high risk of progression—such as those with a glomerular filtration rate below 30, albuminuria of 300 milligrams per day or more, or a rapidly declining glomerular filtration rate—should be promptly referred to a kidney specialist (PMID 31573641).

A single number on the test report does not determine the stage. The definition requires abnormalities to persist for more than three months, staging and risk rely on looking at both scales together, and reading which box a given person falls into is the job of a physician.

What Extinguishes the Lantern

About 30% to 40% of people with diabetes develop diabetic kidney disease (PMID 33121634). In both high- and middle-income countries, as well as a significant number of low-income countries, diabetes and high blood pressure are the leading causes of chronic kidney disease (PMID 27887750).

Diabetic kidney disease is a condition where the kidneys are damaged as a complication of diabetes. It is the most common cause of chronic kidney disease in the United States, and when this disease develops, the risk of other illnesses and death rises significantly (PMID 33121634). Diagnosis is based on persistent albuminuria and a reduced glomerular filtration rate (PMID 39337706). Although leaking protein in the urine has long been thought to precede the decline in kidney function, quite a few people experience a drop in kidney function alone without leaking protein in the urine, and data on this scenario are still scarce (PMID 32236782).

There is encouraging evidence as well. Managing blood sugar and blood pressure, along with using a certain class of blood pressure medications (which we will look at later), makes this disease less likely to occur and slows its progression once it does develop (PMID 27188921). A 2015 review noted that over the preceding 30 years, the rate at which diabetic kidney disease develops has dropped significantly and prognoses have improved, largely thanks to better diabetes management, while also noting that treatments to stop or reverse this disease are still needed (PMID 27188921). Even so, diabetic kidney disease remains the leading cause of end-stage kidney disease (PMID 39337706), and the incidence of chronic kidney disease driven heavily by type 2 diabetes continues to grow worldwide (PMID 40327845).

High blood pressure and chronic kidney disease pull each other along. The vast majority of people with chronic kidney disease have high blood pressure, high blood pressure is a strong factor worsening the course of the heart and kidneys, and declining kidney function worsens high blood pressure in turn (PMID 37053276). Poorly controlled high blood pressure can accelerate the path toward kidney failure (PMID 35653320). Just how low blood pressure should be lowered in chronic kidney disease remains under debate, and diagnosing with reliably measured values, such as blood pressure measured outside the clinic, is important (PMID 37053276).

Obesity is also on the path. A 2026 review noted that obesity has now become more common than diabetes and high blood pressure, making it the most frequent risk factor for chronic kidney disease and its progression (PMID 42175979).

Glomerulonephritis is an umbrella term for conditions where inflammation of the glomeruli impairs their filtering work. For some glomerular diseases or conditions where cysts form in the kidneys, treatments tailored specifically to the condition can help (PMID 34175022). This is why finding the cause is just as important as staging the disease.

Because the common causes are diabetes and high blood pressure, managing chronic kidney disease includes managing those underlying causes.

People Who Live Without Knowing

It is estimated that 13.4% of the world's population has chronic kidney disease, and the majority of them are in stage 3 (PMID 27383068). This figure comes from an analysis pooling 100 studies investigating general populations in various countries, covering about 6.9 million people, and the quality of the pooled studies was uneven. A 2026 review estimates the world's patients at about 850 million and projects that by 2050 this disease will become the fifth leading cause of death globally (PMID 41314225). In the United States, about 14% of adults are considered to have this disease (PMID 37787795). Estimates vary depending on the source and the definition.

In Korea's Korea National Health and Nutrition Examination Survey, 6.2% of adults were classified with this disease from 2007 to 2020, and the proportion rose from 5.1% in 2007–2010 to 7.1% in 2017–2019 (PMID 37037823). Because this survey counted people as having chronic kidney disease if their glomerular filtration rate was below 60 or a single urine protein test was 1+ or higher, the criteria differ from a diagnosis that confirms the condition lasts for three months or more. In the 2011–2012 survey using guideline definitions and an albumin test, the figure was 7.9%, and among people with a glomerular filtration rate of 60 or higher, 5.7% had albuminuria (PMID 27017386). This survey also measured values at a single point in time.

Even though it is this common, reports indicate that fewer than 5% of patients in the early stages answered that they knew they had the disease (PMID 31573641). In Korea as well, across almost all periods of the Korea National Health and Nutrition Examination Survey from 1998 to 2018, fewer than 6% of stage 3 patients knew they had the disease (PMID 36808395). Because there are no symptoms in stages 1 through 3, most people with this disease live without knowing their condition and without receiving a diagnosis (PMID 39162984). A review written about the United States notes that high-risk individuals are rarely monitored annually and that many patients even in moderate or more advanced stages remain undiagnosed — a review leaning on the authors' experience and opinions (PMID 42466120).

Finding it is not difficult. The disease can be found, diagnosed, and staged with simple blood and urine tests (PMID 41314225). One review recommends that individuals at high risk, such as those with diabetes or high blood pressure, have their glomerular filtration rate, urine albumin, and blood pressure measured and recorded regularly (PMID 39162984). The authors of the Korean study also noted that albuminuria preceded the drop in glomerular filtration rate in many patients, suggesting that regularly testing for albuminuria in people with high blood pressure or diabetes can help find the disease in its early stages (PMID 27017386). Guidelines also recommend screening tests that select high-risk individuals, but in practice, this is not well followed (PMID 39137037). Screening the entire population is being studied for its potential in terms of effectiveness and cost (PMID 39137037).

Because this disease is usually diagnosed late or goes undiagnosed, measures to halt its progression are correspondingly delayed or never started (PMID 39137037). Because it is a disease that is found late if you wait for symptoms, chronic kidney disease is found through testing, particularly in high-risk individuals. Evidence is accumulating that finding it early through testing can prevent or slow the downward slope of kidney function and heart and blood vessel disease (PMID 39137037). The occurrence and progression of this disease also differ according to social circumstances, and people who have difficulty accessing services shoulder a greater share (PMID 27887750).

The Heart Before the Kidneys

For someone with chronic kidney disease, dying prematurely is 5 to 10 times more likely than reaching kidney failure (PMID 27887750). This is not compared to the general public; it compares which of the two outcomes is more common in people who already have the disease. The risk of dying early climbs steeply as kidney function worsens, most of these deaths are due to diseases of the heart and blood vessels, and the occurrence of and death from cancer also increase (PMID 27887750).

Cardiovascular disease is an umbrella term for conditions affecting the heart and blood vessels, including coronary artery disease, stroke, heart failure, and arrhythmias. Chronic kidney disease raises the risk of coronary artery disease, stroke, heart failure, arrhythmias, and sudden cardiac death (PMID 40196891). Most people with progressing chronic kidney disease die from cardiovascular disease before reaching kidney failure (PMID 37249051), and for most people with chronic kidney disease, disability or death arrives via cardiovascular disease rather than kidney failure (PMID 41314225). Kidney failure does happen, but events on the heart and blood vessel side are more common than that (PMID 40921075).

The reasons are thought to be multiple. In addition to sharing risk factors like diabetes and high blood pressure, factors are added such as inflammation, anemia, excess fluid accumulation in the body, and substances that build up because the kidneys cannot clear them (PMID 40196891). Albuminuria is both a marker of chronic kidney disease progression and a marker of cardiovascular disease risk, and an increase in albumin leaking into the urine reflects damage to the kidneys along with disease in the blood vessels throughout the body (PMID 38214258).

High blood pressure, anemia, and disruptions in the body's acid-base and bone balance also add a burden to heart disease and quality of life, and are monitored and treated together (PMID 39885176). The principles by which the kidneys handle red blood cell signaling and bone maintenance are traced in "How Do the Kidneys Filter Blood? — A Sieve That Takes Almost Everything Back". Therefore, the goals of chronic kidney disease treatment include slowing the downhill slide of kidney function, preventing cardiovascular disease, and treating metabolic complications (PMID 40921075). For most people with chronic kidney disease, disease of the heart and blood vessels arrives before kidney failure.

Guarding the Remaining Flame

Several treatments that slow the decline of kidney function while also lowering cardiovascular risk have been confirmed in large clinical trials since 2019 (PMID 41314225). Ahead of them lies an old foundation. Blood pressure and blood sugar management, cholesterol-lowering medications, and dietary management are the general principles of care (PMID 38052474). Management also includes reducing cardiovascular risk, treating albuminuria, avoiding medications that can harm the kidneys (such as nonsteroidal anti-inflammatory drugs), and adjusting drug doses to fit kidney function (PMID 31573641).

Returning to the lantern metaphor, one pillar of slowing the process is lightening the load carried by the remaining compartments. Two drug classes are used to lighten the load on the remaining nephrons (PMID 39885176). Renin-angiotensin system blockers are a class of blood pressure medications that block the hormone chain that raises blood pressure and causes the body to retain salt. SGLT2 inhibitors are a class of diabetes medications that block the pathway where the kidneys reabsorb filtered glucose, causing the glucose to be excreted in the urine. This diabetes class was initially used to lower blood sugar, but its effect of protecting the kidneys and heart over the long term came to light (PMID 40736512). Both classes can protect kidney function by lowering the pressure inside the glomerulus, regardless of blood pressure or blood sugar (PMID 34175022).

A randomized controlled trial is a study that divides participants randomly, like drawing lots, gives the medicine to only one group, and compares the results with the other group. There is an analysis pooling 10 randomized controlled trials of this diabetes drug class involving 70,361 people who had either type 2 diabetes, chronic kidney disease, or heart failure (PMID 41203232). Worsening of kidney disease (a composite of kidney failure, a drop in the glomerular filtration rate by half or more, and death from kidney failure) translated to 40.3 events for the placebo group and 25.4 events for the drug group when converted to the equivalent of following 1,000 people for one year (PMID 41203232). This effect appeared regardless of the initial glomerular filtration rate or the amount of albuminuria, and included people in stage 4 and those with little to no albuminuria. The rate at which the glomerular filtration rate declined each year was also slowed across all subgroups, and the magnitude varied by subgroup (PMID 41203232). The authors concluded that these results support the routine use of this class in people with type 2 diabetes, chronic kidney disease, or heart failure, regardless of their level of kidney function (PMID 41203232). Which medication is right for an individual is something to be determined with a doctor in clinical practice.

In another analysis pooling 13 trials, the effects were similar in people with and without diabetes (PMID 36351458). In yet another analysis pooling 15 trials, the risk of patients with chronic kidney disease being hospitalized for heart failure for the first time was relatively 32% lower compared to the placebo (PMID 38768620).

Clinical guidelines have come to recommend using these two classes together as foundational treatment for chronic kidney disease whether diabetes is present or not, but uptake has been slow to increase, particularly in people without diabetes (PMID 39162984). Side effects differ by class, and in trials of patients with type 2 diabetes, this diabetes drug class was reported alongside genital infections (PMID 37024129). In trials of people with both type 2 diabetes and chronic kidney disease, risks beyond what was already known were not apparent for this class, though some safety outcomes differed by drug (PMID 30697905).

These treatments also cannot relight the compartments that have gone out. Current treatments only slow progression (PMID 32060481), and even in large trials using these drugs, the residual risk to the heart and kidneys remained high (PMID 40327845).

The evidence for diet and weight must be read with caution. There is a view that a plant-focused diet reduced in protein and salt may help protect kidney function longer, but the description remains at "may help" (PMID 34175022). Because diet in chronic kidney disease is a matter of tailoring protein, phosphorus, potassium, sodium, and calcium to the individual, medical nutrition therapy with a dietitian is cited as an important part of care (PMID 34579153). Weight loss in people who already have chronic kidney disease has been associated with reduced albuminuria, but the long-term effects on kidney function and survival are less studied and must be determined individually for each person (PMID 40085173).

Current treatments cannot relight an extinguished lantern, but they lighten the load on the remaining flame to slow the speed at which it goes out.

From a Single Line on the Lab Report to the Examining Room

Let us suppose that a person who has had type 2 diabetes for 10 years receives a checkup report showing an estimated glomerular filtration rate a little below 60. They feel no pain. Being without symptoms is a common picture in this disease (PMID 27887750).

Because the definition requires an abnormality lasting for three months or longer, a single number does not pin down the disease, and it is measured again to confirm. If the abnormality persists for three months or more, the glomerular filtration rate and urine albumin—two scales—are looked at together to determine the box (PMID 31573641). Although this is an association from observational studies, even in the lightest box of this disease worse outcomes were more frequent (PMID 37787795), so rather than closing the matter with "it is near the line so it is fine," reading the box is the task of the physician.

If chronic kidney disease is confirmed, the first cause that comes to mind for this person is diabetes. Even so, separating kidney disease in a person with diabetes from kidney disease of other causes goes into clinical care (PMID 28280116), and it is not uncommon for kidney function alone to decline even when protein does not leak into the urine (PMID 32236782).

Once confirmed, in the examining room the physician and patient look together at blood pressure, blood sugar, and the risks to the heart and blood vessels, and decide right there whether to use classes of drugs that lighten the load on the remaining nephrons (PMID 39885176, PMID 40921075). This is because people with both chronic kidney disease and type 2 diabetes are more likely to die from heart and blood vessel disease than to progress to kidney failure at any stage, and the residual risk remains high even with treatment (PMID 40327845). If the glomerular filtration rate declines rapidly or albuminuria is heavy, referral to a nephrologist is the recommendation of a review article (PMID 31573641). If it is chronic kidney disease, the nephrons already lost do not return, and the goal of treatment lies in keeping what remains for a long time.

Where to Look Next

There are still no treatments that revive lost nephrons or stop the progression, and methods targeting the process of scar accumulation are being tested (PMID 32060481). Whether screening the entire population brings benefits is also still under study (PMID 39137037).

The principle of how kidneys filter and reclaim blood, and the question of reading numbers that decline with age, begin in "How Do the Kidneys Filter Blood? — A Sieve That Takes Almost Everything Back". How to read numbers like creatinine, eGFR, and urine albumin one by one is followed by "Reading Your Kidney Test Results — A Sieve You Cannot See, What Stays Behind and What Leaks Through", sudden kidney damage by "What Is Acute Kidney Injury? — A Tap That Suddenly Runs Dry, and Three Places to Look", and dialysis, transplantation, and the path of care without dialysis by "Dialysis and Kidney Transplantation — Three Sieves That Stand In, and the Path That Uses None".

Two common causes continue in "What Is Diabetes? — The Letter That Never Comes, the Letter That Isn't Read" and "What Blood Pressure Measures — Two Numbers, and an Answer That Changes With Where You Measure". The numbers for diabetes are covered by "What Do Blood Sugar Tests Measure? — Three Numbers, and the Lines Each Organization Drew". The heart risks that rise alongside this disease can be seen in "How the Heart Moves Blood — Four Chambers, Four Doors, Two Loops" and "What Coronary Artery Disease Is — The Road That Finds the Heart, Narrowed and Blocked".

How the numbers measured in trials, such as albuminuria or the slope of the glomerular filtration rate, connect to patient outcomes is handled by "Better Numbers, Better Patients? — An Introduction to Surrogate Endpoints", and how to read figures like 40.3 cases per 1,000 versus 25.4 cases, or a relative 32%, as stories of actual people is handled by "If the Risk Was Cut in Half, How Many Fewer People Got Sick? — Relative and Absolute Risk". The benefits and limits of finding symptomless people through testing can be started in "What a Test Actually Tells You — An Introduction to Sensitivity, Specificity, and Pretest Probability".

Source Papers

• "Chronic Kidney Disease." (2017) — PMID 27887750 — Occurrence and progression vary by social determinants, with disparities in access concentrated in vulnerable groups; defined as GFR below 60 or damage markers for 3 months or more, regardless of cause. In high-, middle-, and many low-income countries, the leading causes are diabetes and hypertension. Many people are asymptomatic or experience fatigue, itching, or loss of appetite, being diagnosed incidentally during checkups or after symptoms become severe. GFR is the best indicator (measured via exogenous markers or calculation formulas). Premature death is 5 to 10 times more common than progression to end-stage disease, surging with declining function and consisting mainly of cardiovascular death, alongside increased cancer.
• "Chronic Kidney Disease Diagnosis and Management: A Review." (2019) — PMID 31573641 — Defined as GFR<60 or albuminuria ≥30 mg/24h for over 3 months. Affects 8 to 16% globally, with an early-stage patient awareness rate below 5%. Combined staging and risk assessment using GFR and albuminuria guide treatment, monitoring, and referral. Management involves reducing cardiovascular risk, treating albuminuria, avoiding nephrotoxic drugs, and adjusting drug doses. High-risk cases (eGFR<30, albuminuria ≥300, rapid decline) are referred to nephrology.
• "Chronic kidney disease." (2025) — PMID 39885176 — Hypertension, anemia, metabolic acidosis, and hyperparathyroidism require diagnosis and treatment. Defined as sustained abnormalities affecting health, with adults experiencing lifelong continuous damage and frequent comorbid risk factors. The common mechanism of progression is irreversible loss of nephrons plus overload in the remaining nephrons leading to further loss. Kidney failure without replacement therapy is fatal. Overload in the remaining nephrons is reduced by RAS and SGLT2 inhibitors.
• "Chronic kidney disease." (2026) — PMID 41314225 — Approximately 850 million affected globally, with about 4 million requiring replacement therapy; projected to be the 5th leading cause of death by 2050. Simple tests allow screening, diagnosis, and staging. Most experience disability and death from cardiovascular disease before kidney failure. Since 2019, large randomized trials have identified treatments that simultaneously lower progression and cardiovascular risk.
• "A population-based approach for the definition of chronic kidney disease: the CKD Prognosis Consortium." (2012) — PMID 22038337 — eGFR and albuminuria are independently associated with mortality and kidney failure, consistent across continents. Supports the cutoff of 60, while noting 60 to 74 may also represent an early stage.
• "Harmonizing acute and chronic kidney disease definition and classification." (2021) — PMID 34252450 — Kidney abnormalities lasting 3 months or less are defined as acute kidney disease (AKD).
• "Targeting the progression of chronic kidney disease." (2020) — PMID 32060481 — Characterized by slow, progressive, and irreversible nephron loss. Current treatments have limited efficacy and merely slow progression, necessitating new approaches to halt or reverse the process, focusing on fibrosis targets.
• "Chronic kidney disease." (2021) — PMID 34175022 — A progressive disease with no cure. Plant-based, low-protein, and low-salt diets might be helpful. RAAS and SGLT2 inhibitors lower intraglomerular pressure independently of blood pressure and blood sugar to preserve function. Some glomerular and cystic diseases may benefit from disease-specific treatments.
• "[Chronic kidney disease: classification, mechanisms of progression and strategies for renoprotection]." (2005) — PMID 15880190 — KDIGO proposed definitions and stages ranging from damage (preserving function) to kidney failure.
• "Global Prevalence of Chronic Kidney Disease - A Systematic Review and Meta-Analysis." (2016) — PMID 27383068 — Included 100 observational studies with about 6.9 million participants (diverse populations). Prevalence was 13.4%, with the majority at stage 3. Stage-specific eGFR boundaries are 1: >90+ACR>30, 2: 60~89+ACR>30, 3: 30~59, 4: 15~29, and 5: <15.
• "Estimated Glomerular Filtration Rate, Albuminuria, and Adverse Outcomes: An Individual-Participant Data Meta-Analysis." (2023) — PMID 37787795 — Affects about 14% of US adults. eGFR is calculated using equations based on creatinine alone or creatinine plus cystatin C. In 114 cohorts with about 27.5 million participants, lower eGFR and higher UACR were associated with 10 adverse outcomes, even including the mildest categories (retrospective analysis).
• "Cardiovascular complications in chronic kidney disease." (2023) — PMID 37249051 — Classified into 5 stages, with G5 representing kidney failure. Most patients with progressing chronic kidney disease die of cardiovascular death before reaching kidney failure.
• "Diabetic Kidney Disease." (2020) — PMID 33121634 — The most common cause of chronic kidney disease in the United States, occurring in 30 to 40% of patients with diabetes and significantly increasing morbidity and mortality risks.
• "Novel Insights into Diabetic Kidney Disease." (2024) — PMID 39337706 — Diagnosis is based on persistent albuminuria and reduced eGFR. Despite therapeutic advances, it remains the leading cause of end-stage renal disease.
• "Nonproteinuric diabetic kidney disease." (2020) — PMID 32236782 — A substantial number of patients with diabetes experience a decline in kidney function without proteinuria.
• "Diabetic kidney disease." (2015) — PMID 27188921 — Blood sugar and blood pressure control alongside RAAS blockade reduce incidence and slow progression. The decline in incidence over the past 30 years is largely attributable to improved diabetes management. Treatments for prevention, arrest, or reversal remain an unmet need.
• "Hypertension as Cardiovascular Risk Factor in Chronic Kidney Disease." (2023) — PMID 37053276 — The vast majority of chronic kidney disease patients have hypertension in a bidirectional relationship. Target blood pressure is debated, and reliable measurements like ambulatory or home blood pressure are needed. Residual cardiovascular risk remains high even after target achievement.
• "Hypertension and the kidneys." (2022) — PMID 35653320 — Uncontrolled hypertension accelerates progression to end-stage renal disease.
• "Obesity in CKD: Core Curriculum 2026." (2026) — PMID 42175979 — The prevalence of obesity has surpassed diabetes and hypertension to become the most common risk factor for chronic kidney disease and its progression.
• "Diagnosis and Management of Type 2 Diabetic Kidney Disease." (2017) — PMID 28280116 — Addresses the clinical differentiation between diabetic and non-diabetic kidney disease.
• "Early Identification and Management of Chronic Kidney Disease." (2024) — PMID 39162984 — Stages 1 to 3 are asymptomatic, leaving most patients unaware and undiagnosed. High-risk groups require regular measurement of eGFR, UACR, and blood pressure. Guidelines recommend SGLT2 inhibitors alongside RAAS inhibitors as foundational therapy regardless of diabetes status, though adoption is slow particularly in non-diabetic patients.
• "Addressing Unmet Needs in the Management of Chronic Kidney Disease." (2026) — PMID 42466120 — Annual surveillance of high-risk groups is rare, and a substantial proportion of moderate-to-severe cases remain undiagnosed (a review based on author experience and opinion).
• "Screening for chronic kidney disease: change of perspective and novel developments." (2024) — PMID 39137037 — Usually diagnosed late or left undiagnosed. Screening can prevent or delay functional decline and cardiovascular disease. Guidelines recommend targeted screening for high-risk groups, but adherence is low, and population-wide screening is being studied for potential efficacy and cost-effectiveness.
• "Cardiovascular disease in chronic kidney disease." (2025) — PMID 40196891 — Increased risk of coronary artery disease, stroke, heart failure, arrhythmias, and sudden death, driven by common risk factors alongside inflammation, anemia, fluid overload, and uremic toxins.
• "Chronic Kidney Disease." (2025) — PMID 40921075 — Progression can lead to end-stage renal disease, but cardiovascular events are more common. Treatment goals are slowing functional decline, preventing cardiovascular disease, and treating metabolic complications.
• "Albuminuria: An Underappreciated Risk Factor for Cardiovascular Disease." (2024) — PMID 38214258 — Albuminuria is a marker of chronic kidney disease progression and cardiovascular risk, reflecting both kidney damage and systemic vascular disease.
• "Advances in the management of chronic kidney disease." (2023) — PMID 38052474 — General principles of management include blood pressure and blood sugar control, RAAS blockade, statins, and dietary management, alongside low public awareness.
• "SGLT2 inhibitors and acute kidney injury." (2026) — PMID 40736512 — Diabetes drugs that block glucose reabsorption in the proximal tubule, providing long-term protection to the kidneys and heart beyond blood sugar control.
• "SGLT2 Inhibitors and Kidney Outcomes by Glomerular Filtration Rate and Albuminuria: A Meta-Analysis." (2026) — PMID 41203232 — In 10 randomized trials with 70,361 participants (type 2 diabetes, chronic kidney disease, or heart failure), progression was 25.4 versus 40.3 per 1,000 patient-years (HR 0.62), regardless of baseline eGFR and albuminuria (including stage 4 and cases with little to no albuminuria).
• "Impact of diabetes on the effects of SGLT2 inhibitors on kidney outcomes." (2022) — PMID 36351458 — Across 13 trials with 90,409 participants, progression risk was reduced by 37%, similarly regardless of diabetes status.
• "Effect of SGLT2 inhibitors on heart failure outcomes and cardiovascular death across the cardiometabolic disease spectrum." (2024) — PMID 38768620 — First heart failure hospitalization was reduced by 32% in chronic kidney disease patients.
• "Benefits and harms of drug treatment for type 2 diabetes." (2023) — PMID 37024129 — Network meta-analysis of 816 randomized trials for type 2 diabetes; harms are class-specific, such as genital infections with SGLT2 inhibitors.
• "Effect of SGLT2 inhibitors on cardiovascular, renal and safety outcomes in patients with type 2 diabetes mellitus and chronic kidney disease." (2019) — PMID 30697905 — Reduced cardiovascular and kidney outcomes in type 2 diabetes with chronic kidney disease, with no evidence of risks beyond those already known for the class.
• "Rapid and Simultaneous Initiation of Guideline-Directed Kidney Therapies in Patients with CKD and Type 2 Diabetes." (2025) — PMID 40327845 — Chronic kidney disease occurrence continues to rise globally, driven largely by type 2 diabetes. Patients with chronic kidney disease and type 2 diabetes are more likely to experience cardiovascular death than progression to kidney failure at any stage, and residual risk remains high despite treatment.
• "Chronic Kidney Disease: Role of Diet for a Reduction in the Severity of the Disease." (2021) — PMID 34579153 — Monitoring of protein, phosphorus, potassium, sodium, and calcium, with medical nutrition therapy by a dietitian being important.
• "Obesity and Metabolic Health in CKD." (2025) — PMID 40085173 — Weight loss is associated with improvement in albuminuria in existing chronic kidney disease, though long-term effects on function and survival are less studied and require individualization.
• "National trends in the prevalence of chronic kidney disease among Korean adults, 2007-2020." (2023) — PMID 37037823 — In the Korea National Health and Nutrition Examination Survey of 80,010 adults, defined as eGFR<60 or urine protein 1+ or greater on a single test, prevalence was 6.2%, shifting from 5.1% in 2007–2010 to 7.1% in 2017–2019, and decreasing to 6.5% in 2020.
• "Trends in chronic kidney disease awareness and related clinical and demographic characteristics from 1998 to 2018 in Koreans." (2023) — PMID 36808395 — Stage 3 awareness was below 6.0% across all periods except one, showing consistently low awareness in Korea.
• "Prevalence of chronic kidney disease defined by using CKD-EPI equation and albumin-to-creatinine ratio in the Korean adult population." (2016) — PMID 27017386 — Prevalence was 7.9%. Among those with GFR≥60, albuminuria (ACR≥30) was present in 5.7%. Many patients exhibit albuminuria before a decline in GFR, suggesting routine albuminuria testing in high-risk groups (hypertension, diabetes) can aid early detection.