From the Guidelines
Kidney disease progresses through five distinct stages, each characterized by declining kidney function measured by glomerular filtration rate (GFR), with the most recent and highest quality study 1 providing the framework for understanding these stages.
Stages of Kidney Disease
The stages of kidney disease are defined as follows:
- Stage 1: Normal kidney function (GFR ≥90 ml/min) with signs of kidney damage like protein in urine.
- Stage 2: Mild decrease in kidney function (GFR 60-89 ml/min) with continued evidence of kidney damage.
- Stage 3: Moderate kidney damage, divided into 3a (GFR 45-59 ml/min) and 3b (GFR 30-44 ml/min), where symptoms like fatigue and fluid retention may begin.
- Stage 4: Severe kidney damage (GFR 15-29 ml/min) with more pronounced symptoms including nausea, vomiting, and difficulty concentrating.
- Stage 5: Kidney failure or end-stage renal disease (GFR <15 ml/min), requiring dialysis or kidney transplantation for survival.
Importance of Early Detection
Early detection through regular blood and urine tests is crucial, as kidney function deteriorates gradually and often without noticeable symptoms until advanced stages, as noted in 1 and 1.
Management
Management focuses on treating underlying causes like diabetes and hypertension, controlling blood pressure, maintaining proper diet, and medication adjustments as kidney function declines, with considerations for the degree of albuminuria and observed history of eGFR loss influencing treatment decisions, as discussed in 1.
From the Research
Stages of Kidney Disease
The stages of kidney disease are typically classified based on the estimated glomerular filtration rate (eGFR), which measures the level of kidney function. The following are the general stages of kidney disease:
- Stage 1: eGFR ≥ 90 mL/min/1.73 m2, kidney damage with normal or high eGFR
- Stage 2: eGFR 60-89 mL/min/1.73 m2, kidney damage with mild decrease in eGFR
- Stage 3: eGFR 30-59 mL/min/1.73 m2, moderate decrease in eGFR
- Stage 4: eGFR 15-29 mL/min/1.73 m2, severe decrease in eGFR
- Stage 5: eGFR < 15 mL/min/1.73 m2, kidney failure
Management of Kidney Disease
The management of kidney disease often involves the use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) to slow the progression of kidney disease and reduce the risk of cardiovascular events 2, 3, 4, 5, 6. However, the use of these medications in patients with advanced kidney disease is still a topic of debate.
Use of ACEIs and ARBs in Kidney Disease
Studies have shown that ACEIs and ARBs can be beneficial in patients with kidney disease, but their use may need to be adjusted based on the level of kidney function 2, 3, 4. For example, a study found that patients with heart failure and reduced eGFR were less likely to receive ACEIs/ARBs despite their association with lower mortality 2. Another study found that the use of ACEIs/ARBs in patients with advanced kidney disease was not associated with a significant reduction in cardiovascular events 3.
Monitoring and Adjustment of ACEIs and ARBs
It is essential to monitor kidney function and adjust the dose of ACEIs and ARBs as needed to minimize the risk of adverse effects such as hyperkalemia and declining renal function 4, 6. A study found that the use of high doses of ACEIs/ARBs in patients with heart failure and chronic kidney disease was not associated with adverse changes in renal function 4.