The stages of renal failure vary in severity

In medicine, the disease is divided into stages according to the severity of renal failure. The four most common stages are the compensated renal insufficiency stage, the decompensated renal insufficiency stage, the renal failure stage, and the uremia stage.

(A) Compensatory stage of renal insufficiency : When the damage to the renal unit does not exceed 50% of the normal level (creatinine clearance 80-50 ml/min), there is compensation of reserve renal function without increase of metabolites such as blood urea nitrogen, blood creatinine is maintained at normal levels, and there are no clinical symptoms except for increased nocturia.

(ii) Decompensated renal failure: more than 50% of renal units are damaged (creatinine clearance 50-20 ml/min), blood creatinine reaches 133-442 μmol/L (2-5 mg/dl), blood urea nitrogen exceeds 7.1 mmol/L (20 mg/dl), and the patient may have clinical manifestations such as weakness, poor appetite, and mild anemia.

(III) Renal failure stage: serum creatinine rises to 442-707 μmol/L (5-8 mg/dl), creatinine clearance rate decreases to 20-10 ml/min, blood urea nitrogen rises to 17.9-28.6 mmol/L (50-80 mg/dl), and the patient develops multiple clinical manifestations of various systems such as anemia, water-electrolyte-acid-base imbalance, etc.

(IV) Uremic stage : serum creatinine reaches 707 μmol/L (8 mg/dl) or above, creatinine clearance rate drops below 10 ml/min, blood urea nitrogen exceeds 28.6 mmol/L (80 mg/dl), and the patient has obvious acidosis, anemia and severe systemic symptoms.

In recent years, according to the internationally recognized K/DOQI guidelines, chronic kidney disease is clinically divided into five stages according to the level of glomerular filtration rate, among which stages 2 to 5 are different stages of CRF progression:

1. Renal damage with normal or elevated GFR (≥90ml/min.1.73m2)

2. Renal damage with mild decrease in GFR (60-90 ml/min.1.73 m2)

3. Moderate decrease in GFR (30-59 ml/min.1.73 m2)

4. Severe decrease in GFR (15-29 ml/min.1.73 m2)

5. Renal failure (GFR < 15 ml/min. 1.73 m2)

(Chronic kidney disease refers to renal damage or GFR < 60ml/min.1.73m2 for more than 3 months; renal damage refers to pathological changes in the kidney or damage indicators such as abnormal blood or urine tests, abnormal imaging examinations)

Blood urea nitrogen is greatly affected by many factors such as protein intake, fever and gastrointestinal bleeding, and cannot be used alone as an indicator to measure the severity of renal function damage. Although blood creatinine is relatively stable, its level is low in the elderly and those with muscular atrophy. Creatinine clearance can be used as an indicator for the staging of chronic renal failure. It is conducive to appropriate treatment of patients.