From the Guidelines
Chronic Kidney Disease (CKD) stage 3 signifies moderate kidney damage with a glomerular filtration rate (GFR) between 30-59 mL/min/1.73m², as defined by the most recent guidelines 1. This stage is further divided into stage 3a (GFR 45-59) and stage 3b (GFR 30-44), with stage 3b indicating more severe impairment. At this stage, waste products begin accumulating in the blood as kidneys struggle to filter effectively. Patients may experience symptoms like fatigue, fluid retention, high blood pressure, and changes in urination patterns, though some remain asymptomatic. Management typically includes blood pressure control with medications like ACE inhibitors or ARBs, blood sugar management for diabetics, dietary modifications (reduced sodium, potassium, and phosphorus), and regular monitoring of kidney function every 3-6 months. Some key points to consider in the management of CKD stage 3 include:
- The importance of early detection and intervention to slow disease progression, as emphasized in guidelines from the American College of Cardiology Foundation/American Heart Association 1.
- The use of the simplified MDRD equation to estimate GFR, as described in the guidelines for the management of chronic kidney disease in HIV-infected patients 1.
- The role of screening for early stages of CKD, including measurement of urinary albumin-to-creatinine or protein-to-creatinine ratios, to identify patients at high risk for developing end-stage renal disease (ESRD) 1. Stage 3 represents a critical point where interventions can significantly slow progression to more advanced kidney disease, making lifestyle modifications and medication adherence particularly important. Without proper management, CKD can progress to stages 4 and 5, potentially requiring dialysis or transplantation. It is essential to prioritize morbidity, mortality, and quality of life outcomes when managing CKD stage 3, and to base treatment decisions on the most recent and highest-quality evidence available, such as the guidelines from the National Kidney Foundation 1 and the HIV Medicine Association of the Infectious Diseases Society of America 1.
From the Research
Definition of CKD Stage 3
CKD stage 3 is defined as a glomerular filtration rate (GFR) of 30-59 ml/min/1.73 m(2) for 3 months or more, irrespective of cause 2. This stage is further subdivided into two subgroups: stage 3A (45 < eGFR < 60 ml/min/1.73 m(2)) and stage 3B (30 < eGFR < 45 ml/min/1.73 m(2)) 3.
Characteristics of CKD Stage 3
Some key characteristics of CKD stage 3 include:
- A decreased GFR, which can be estimated using various equations such as the Modification of Diet in Renal Disease (MDRD) Study equation or the Cockcroft-Gault formula 4, 2
- The presence of kidney damage, which can be ascertained by the presence of albuminuria, defined as albumin-to-creatinine ratio >30 mg/g in two of three spot urine specimens 2
- An increased risk of progression to end-stage renal disease (ESRD) and cardiovascular disease (CVD) 3, 2
Risk Factors for Progression of CKD Stage 3
Some risk factors for progression of CKD stage 3 include:
- Macroalbuminuria (hazard ratio (HR) 3.06,95% confidence interval (CI) 1.48-2.89, p < 0.001) 3
- Microalbuminuria (HR 1.99 95% CI 1.04-3.85, p = 0.038) 3
- Microscopic haematuria (HR 2.07 95% CI 1.48-2.89, p < 0.001) 3
- Stage 3B CKD (HR 2.99 95% CI 2.19-4.10, p < 0.001) 3
Prevalence of Metabolic Complications in CKD Stage 3
The prevalence of metabolic complications in adults with CKD stage 3 is relatively low, with haemoglobin <110 g/l occurring in 3.5% of patients with MDRD GFR between 30 and 60 ml/min/1.73 m(2) 5. However, the prevalence of complications increases with decreasing GFR, with 42.2% of patients with MDRD GFR <30 ml/min/1.73 m(2) having haemoglobin <110 g/l 5.