Chronic kidney disease (CKD): stages, symptoms & modern therapy

At a glance

FrequencyAccording to estimates affects about one in ten adults in Germany — many do not know about it
DefinitionKidney damage or reduced kidney function (eGFR < 60) over at least three months
Most common causesDiabetes and high blood pressure — together responsible for a large part of cases
Key valueseGFR (estimated glomerular filtration rate) and UACR (urine albumin-creatinine ratio)
TherapyBlood pressure control, ACE inhibitors/ARBs, SGLT2 inhibitors, if needed finerenone — lifestyle, avoiding nephrotoxic medications
ICD-10N18 (chronic kidney disease)

Table of contents

  1. What is CKD?
  2. Stages
  3. Symptoms
  4. Causes and risk factors
  5. Diagnosis
  6. Therapy: kidney protection
  7. Nutrition
  8. Dialysis and transplantation
  9. Living with CKD
  10. How brite helps you
  11. FAQ
  12. Related topics

1. What is CKD?

Chronic kidney disease (CKD) means that the kidneys are restricted in their function over a longer period (at least three months) or that there is structural kidney damage. The kidneys normally filter waste products and excess water out of the blood, regulate the blood pressure, the mineral balance and blood formation.¹

According to estimates, CKD affects about one in ten adults in Germany — most do not know about it for a long time, because the disease generally causes no complaints in the early stages. With progressing kidney damage, the risk of cardiovascular diseases and the overall mortality rise considerably.¹˒²

The good news: therapy has fundamentally improved In recent years, new medications have become available — above all SGLT2 inhibitors and finerenone — that can demonstrably slow the course of CKD. The prerequisite: the disease is recognized early and treated consistently.

2. Stages

CKD is classified according to the KDIGO classification on the basis of two parameters: the eGFR (estimated kidney function) and the albuminuria (protein in the urine).¹

GFR stages

G1 eGFR ≥ 90
Normal or increased kidney function, but indications of kidney damage (e.g. albuminuria)
G2 eGFR 60–89
Mildly reduced with indications of kidney damage
G3a eGFR 45–59
Mildly to moderately reduced
G3b eGFR 30–44
Moderately to severely reduced
G4 eGFR 15–29
Severely reduced
G5 eGFR < 15
Kidney failure — generally dialysis or transplantation necessary

Albuminuria categories

  • A1: normal to mildly increased
  • A2: moderately increased — an important early indicator of kidney damage and cardiovascular risk
  • A3: severely increased

The higher the stage and the stronger the albuminuria, the higher the risk of a progression of the disease and of cardiovascular complications.¹

3. Symptoms

Early stages: hardly any complaints CKD generally causes no complaints in the early stages — which is why it is often only discovered late. Symptoms mostly only occur in advanced stages.
  • Fatigue and reduced performance
  • fluid retention (edema) — especially in the legs, feet and face
  • shortness of breath
  • Nausea, loss of appetite
  • itching
  • concentration disturbances
  • changed urine quantity (more or less than normal), foamy urine
  • High blood pressure — often both a cause and a consequence of CKD
  • anemia (a lack of blood) — the kidneys produce less erythropoietin

4. Causes and risk factors

  • Diabetes: The most common cause of CKD. Type 2 diabetes and type 1 diabetes can damage the small blood vessels of the kidneys (diabetic nephropathy).
  • High blood pressure: The second most common cause. Long-term elevated blood pressure damages the kidney vessels. At the same time, CKD can further raise the blood pressure — a vicious circle.
  • Glomerulonephritis: Inflammatory kidney diseases of various causes.
  • Polycystic kidneys (ADPKD): A hereditary disease with the formation of cysts in the kidneys. The most common hereditary kidney disease.
  • Urinary tract diseases: Recurrent urinary tract infections, urinary outflow disorders, kidney stones.
  • Medications: Long-term intake of NSAIDs (ibuprofen, diclofenac), certain antibiotics, contrast agents. More: Drug interactions.
  • Other risk factors: age, obesity, smoking, familial predisposition, heart failure.

5. Diagnosis

The diagnosis of a CKD is generally uncomplicated — if one thinks of it.¹

  • eGFR (estimated GFR): is calculated from the creatinine in the blood. The most important value for assessing the kidney function. In certain situations, cystatin C can additionally be determined for a more precise estimate.
  • UACR (urine albumin-creatinine ratio): A simple urine test that detects an increased protein excretion. The KDIGO guideline 2024 emphasizes the importance of the UACR, especially for screening and for risk assessment.¹
  • Urine sediment and dipstick: Indications of blood, protein or inflammation in the urine.
  • Blood pressure: measure regularly.
  • Ultrasound of the kidneys: size, shape, signs of congestion, cysts, stones.
  • Blood values: potassium, phosphate, calcium, urea, blood count (anemia?), HbA1c (diabetes?).
Screening for at-risk people — KDIGO 2024 The KDIGO guideline 2024 recommends a regular CKD screening with eGFR and UACR for people with diabetes, high blood pressure or other risk factors. Early stages of CKD are often still treatable well — the later the diagnosis, the worse the prognosis.

More: Preparing for a doctor's appointment, Understanding blood values.

6. Therapy: kidney protection

The goal of therapy is to slow the progression of CKD, prevent complications and lower the cardiovascular risk. The KDIGO guideline 2024 defines a multi-pillar nephroprotective strategy.¹

Pillar 1 Blood pressure control & RAS inhibitors

Systolic target value generally below 120 mmHg according to KDIGO 2024. RAS inhibitors (ACE inhibitors or ARBs) are generally the agents of choice with CKD with albuminuria — they not only lower the blood pressure, but also act directly nephroprotectively.¹

Pillar 2 SGLT2 inhibitors — the new pillar
Dapagliflozin, empagliflozin and others
Can lower the progression of kidney damage and the cardiovascular risk — regardless of whether diabetes is present. Are recommended by KDIGO 2024 with a strong recommendation.¹
Pillar 3 Further modern options
Finerenone (non-steroidal MRA)
A new mineralocorticoid receptor antagonist that can reduce the progression of kidney damage and cardiovascular events with CKD with diabetes. Is recommended in KDIGO 2024.¹
GLP-1 receptor agonists (e.g. semaglutide)
Can reduce cardiovascular and renal events in CKD patients with diabetes and/or obesity. Are listed in KDIGO 2024 as a new therapy option.
Accompanying Diabetes, lifestyle & medication review
  • Diabetes control: with diabetic nephropathy, good blood sugar control (HbA1c target value individual) is decisive.
  • Lifestyle: stopping smoking, weight control, regular exercise, salt reduction.
  • Medication review: dose adjustment with reduced kidney function, observe sick-day rules (pause certain medications during an acute illness). More: Stopping medications.
Caution: avoid NSAIDs with CKD NSAIDs (ibuprofen, diclofenac and co.) can worsen the kidney function and should generally be avoided with CKD — especially in higher stages. Contrast agents and certain antibiotics can also burden the kidneys. With pain, coordinate with the treating practice as to which alternatives come into question.

7. Nutrition

  • Reduce salt: can improve blood pressure and edema.
  • Protein: KDIGO 2024 recommends a moderate protein intake for most CKD patients — no strict restriction, but also no excess.
  • Potassium: in advanced stages a potassium-adjusted diet can be necessary — plant potassium is less bioavailable than potassium from highly processed foods.
  • Phosphate: avoid foods with added phosphate (ready meals, cola, processed cheese).
  • Nutritional counseling: professional nutritional counseling is generally recommended — above all in advanced stages.

8. Dialysis and transplantation

When the kidney function declines so far that the body can no longer excrete waste products and water sufficiently, a renal replacement therapy becomes necessary — generally from stage G5.¹

Hemodialysis
The blood is cleaned outside the body via a machine. Generally three times per week for several hours in the dialysis center. Home hemodialysis is an option for some patients.
Peritoneal dialysis
The peritoneum serves as a filter. Can generally be carried out at home — offers more flexibility in everyday life.
Kidney transplantation
The best long-term therapy for most patients with kidney failure. Can be done as a living donation or from brain-dead organ donors. The waiting time for a donor organ can be several years in Germany.
Get informed early — already from G4 According to the guideline, the education about renal replacement procedures should take place early — generally already from stage G4 — so that preparations can be made in good time (dialysis access, transplantation work-up).¹

9. Living with CKD

  • Medications: regular and punctual intake. Observe the dose adjustment with reduced kidney function. No NSAIDs without consultation. More: Taking medications correctly.
  • Checks: regular blood and urine checks (eGFR, UACR, potassium, blood count). The intervals are based on the stage.
  • Blood pressure: measure regularly — ideally at home. Discuss the target values with the practice.
  • Vaccinations: a flu vaccination and a pneumococcal vaccination are generally recommended. With advanced CKD, special vaccination recommendations apply.

How brite helps you with CKD

Ramipril in the morning, dapagliflozin with it, finerenone in the evening, furosemide as needed, plus the phosphate binder with meals — and check eGFR and potassium every three months. CKD therapy is multitasking. brite brings structure to it.

  • Intake reminder — take ACE inhibitors, SGLT2 inhibitors, finerenone, blood pressure reducers punctually — and phosphate binders with meals. brite reminds you reliably, including for the time-critical medications. Set up a reminder
  • Interaction check — NSAIDs with CKD? Potassium-sparing diuretics plus ACE inhibitors? Contrast agent preparation? brite warns about risky combinations that are particularly relevant for the kidney. Check now
  • Health history — document eGFR, UACR, blood pressure, potassium and weight over time. This way you see early when the course is worsening — and can counteract. Track your history
  • Digital medication plan — all medications clearly organized for nephrology, cardiology, diabetology and the GP — especially important because, with CKD, many specialists are involved. Go to medication plan
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FAQ: Common questions about chronic kidney disease

The eGFR (estimated glomerular filtration rate) is the most important laboratory value for assessing the kidney function. It is calculated from the creatinine in the blood and indicates how well the kidneys filter the blood. A value below 60 over at least three months points to a reduced kidney function.¹
In early stages, the progression can generally be slowed or stopped — through blood pressure control, SGLT2 inhibitors and treatment of the underlying disease. Kidney function that has already been lost can, however, mostly not be restored. That is why early detection is so important.
Medications (e.g. dapagliflozin, empagliflozin) that were originally developed for diabetes, but can also protect the kidneys and the heart independently of diabetes. According to KDIGO 2024 they are among the most important new pillars of CKD therapy.¹
Not necessarily. In many patients, the progression of CKD can be slowed so far with modern therapy that dialysis does not become necessary or only becomes necessary considerably later. When the kidney function declines very strongly, however (stage G5), a renal replacement therapy generally becomes necessary.
With CKD, NSAIDs (ibuprofen, diclofenac) should generally be avoided, since they can worsen the kidney function. Alternatives (e.g. paracetamol (acetaminophen)) should be discussed with the treating practice.
Through simple laboratory tests: eGFR (a blood test) and UACR (a urine test). The KDIGO guideline recommends a regular screening for at-risk people (diabetes, high blood pressure, familial predisposition, age). Early CKD stages are generally symptom-free — only tests can discover them.¹
A new non-steroidal mineralocorticoid receptor antagonist that can reduce the progression of kidney damage and cardiovascular events with CKD with diabetes. Is recommended in KDIGO 2024 as a new therapy option.¹
In early stages generally yes — with an emphasis on salt reduction and a balanced diet. In advanced stages, a potassium-, phosphate- and, if needed, protein-adjusted diet can be necessary. Professional nutritional counseling is recommended.

12. Related topics

Type 2 diabetes High blood pressure Heart failure Ibuprofen Understanding blood values Drug interactions

Sources

  1. KDIGO 2024 Clinical Practice Guideline for the Evaluation and Management of CKD. kdigo.org
  2. DEGAM S3-Leitlinie CKD in der Hausarztpraxis (AWMF Reg-Nr. 053-048, Update 2024). degam.de
  3. gesundheitsinformation.de (IQWiG): Chronische Nierenerkrankung. gesundheitsinformation.de
  4. Deutsche Gesellschaft für Nephrologie (DGfN). dgfn.eu
Medical disclaimer: This article is for general information and does not replace medical advice, diagnosis or therapy. With reduced kidney function, medications should generally only be taken, dosed or stopped in consultation with the treating practice. NSAIDs should generally be avoided with CKD. The treatment planning is always determined individually by the nephrology or the GP practice. Last updated: April 2026.