From the Guidelines
Chronic kidney disease (CKD) stage 3 is classified based on estimated glomerular filtration rate (eGFR) values between 30-59 mL/min/1.73m², with two substages: stage 3a (eGFR 45-59 mL/min/1.73m²) and stage 3b (eGFR 30-44 mL/min/1.73m²) 1. To determine CKD staging, healthcare providers use blood tests to measure creatinine levels, which are then used in formulas like the CKD-EPI or MDRD equation to calculate eGFR. For accurate classification, the reduced kidney function must be present for at least three months. Additionally, other markers such as albuminuria (measured as albumin-to-creatinine ratio) should be assessed, as this provides important prognostic information 1. Some key points to consider in the classification and management of CKD stage 3 include:
- The distinction between stage 3a and 3b is important because the risks of mortality and other outcomes vary greatly between these groups 1.
- Albuminuria is strongly predictive of outcomes at all levels of GFR and should be integrated into CKD staging paradigms 1.
- Patients with CKD stage 3 typically require regular monitoring every 3-6 months, with attention to blood pressure control (target <130/80 mmHg), management of metabolic complications like anemia or mineral bone disorders, and medication dose adjustments for drugs cleared by the kidneys. This classification is important because stage 3 represents a moderate reduction in kidney function where interventions can significantly slow progression to more advanced stages. The most recent and highest quality study supporting this classification is from 2014 1, which endorses the new distinction between CKD stage 3a and 3b and the addition of albuminuria into the classification scheme of CKD.
From the Research
Classification of Chronic Kidney Disease Stage 3
Chronic kidney disease (CKD) is classified based on the glomerular filtration rate (GFR) and the presence of kidney damage.
- The GFR is a measure of kidney function, and it is used to classify CKD into five stages, with stage 1 being the least severe and stage 5 being the most severe.
- Stage 3 CKD is characterized by a GFR of 30-59 mL/min per 1.73 m2, indicating moderate kidney damage or decreased kidney function 2.
- The classification of CKD stage 3 is important because it helps to identify patients who are at risk of progressing to more advanced stages of CKD and to initiate appropriate treatment to slow disease progression.
Diagnosis and Treatment of CKD Stage 3
The diagnosis of CKD stage 3 is typically made based on laboratory tests, including serum creatinine and urine albumin-to-creatinine ratio.
- Treatment of CKD stage 3 usually involves lifestyle modifications, such as dietary changes and increased physical activity, as well as medications to control blood pressure and reduce proteinuria 3, 4.
- Angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARB) are commonly used to treat CKD stage 3, as they have been shown to slow disease progression and reduce the risk of cardiovascular events 5, 4.
- Vitamin D supplementation may also be beneficial in patients with CKD stage 3, as it has been shown to reverse the decline in GFR following treatment with ACEi/ARB 6.