Chronic Kidney Disease: Diagnosis and Treatment

The National Kidney Foundation has developed guidelines for classifying chronic kidney disease based on glomerular filtration rate (GFR):

• Stage 1: Normal GFR (> 90 ml/min/1.73 m2 for adults) with persistent albuminuria or structural abnormalities.
• Stage 2: GFR between 60-89 ml/min/1.73 m2 with persistent albuminuria or structural abnormalities.
• Stage 3: GFR between 30-59 ml/min/1.73 m2.
• Stage 4: GFR between 15-29 ml/min/1.73 m2.
• Stage 5 (end-stage renal failure): GFR < 15 ml/min/1.73 m2.

Further testing to determine the underlying etiology may include urinalysis; renal imaging including ultrasound and CT scan; and renal biopsy.

Because the kidneys are essential to regulating electrolyte and acid-base balance, CKD leads to chemistry disorders such as hyperkalemia, hyperphosphatemia, hypocalcemia, and metabolic acidosis.

Treatment

Treatment for CKD aims to reduce the high cardiovascular mortality rate in this high-risk population and to slow disease progression. It is also important to address the underlying etiology, treat related conditions to reduce cardiovascular risk, and replace lost kidney function via dialysis or transplant when uremia develops.

In patients with diabetes mellitus or hypertension, control of blood glucose and blood pressure is very important. The rate of fall of GFR can be reduced or even halted with aggressive blood pressure and glucose control. Angiotensin-converting enzyme (ACE) inhibitors and angiotensin-receptor blockers (ARBs) are especially helpful blood pressure medications for diabetic patients, because they are kidney-protective.

Specific treatments for underlying disorders should be applied. In some cases, addressing the underlying etiology will retard or halt the loss of kidney function.

Sodium restriction and/or diuretics are usually needed to combat fluid retention.

Anemia is common in CKD patients due to the loss of renal erythropoietin production and should be treated with supplemental iron (if iron deficiency is also present) and synthetic erythropoietin to reach a target hemoglobin of 11-12 g/dL. Phosphate binders and dietary phosphorus restriction are indicated to keep phosphate <4.5 mg/dL.

Exercise can benefit patients with CKD. Resistance training in particular helps reduce the catabolic effects of a low-protein (0.6g/kg/day) diet,¹ whereas aerobic exercise may help control blood pressure and lipid levels.²

Ultimately, dialysis or kidney transplantation will be necessary for patients who progress to end-stage kidney failure.