How to increase Glomerular Filtration Rate (GFR)?

How to Increase Glomerular Filtration Rate (GFR)

The most effective interventions to increase GFR include ACE inhibitors or ARBs for blood pressure control, moderate physical activity, appropriate protein intake, and sodium restriction, all of which help optimize kidney hemodynamics and slow progression of kidney disease. 1

Understanding GFR and Its Determinants

• GFR is considered the best overall indicator of kidney health, reflecting the total amount of fluid filtered by the kidneys per unit time 2
• Total GFR is the product of single-nephron GFR and total nephron number, with a mean of approximately 1,000 nephrons in healthy adults 1
• GFR can be estimated (eGFR) using serum biomarkers like creatinine and cystatin C, or directly measured (mGFR) using exogenous filtration markers 1, 3

Evidence-Based Interventions to Increase GFR

Blood Pressure Management

• ACE inhibitors or ARBs should be initiated and titrated to maximally tolerated doses to optimize glomerular hemodynamics and slow CKD progression 4
• Target systolic blood pressure of <120-130 mmHg using standardized office blood pressure measurement 4
• Monitor serum creatinine after starting ACE inhibitors/ARBs; an initial increase up to 30% is acceptable and usually returns to baseline 4
• Caution: ACE inhibitors and ARBs are contraindicated in pregnancy and should be used with caution in women of childbearing potential 1

Dietary Modifications

• Maintain protein intake at approximately 0.8 g/kg/day for patients with CKD not on dialysis 1
• Restrict dietary sodium to <2.0 g/day (<90 mmol/day) to reduce hypertension and optimize kidney hemodynamics 1, 4
• Avoid high-protein diets and creatine supplements which can affect non-GFR determinants of serum creatinine 1

Physical Activity

• Undertake moderate-intensity physical activity for a cumulative duration of at least 150 minutes per week, which improves overall kidney function 1
• Adjust exercise intensity to a level compatible with cardiovascular and physical tolerance 1

Medication Management

• Loop diuretics can be used for edema management in glomerular diseases, with twice daily dosing preferred over once daily dosing 5, 4
• For resistant edema, consider combination therapy with a loop diuretic and a thiazide diuretic 5
• Avoid nephrotoxic medications, especially NSAIDs, which can reduce GFR 4

Special Considerations for Different Patient Groups

Diabetic Patients

• For patients with diabetes and CKD, maintain individualized HbA1c targets ranging from <6.5% to <8.0% 1
• In children and adolescents with diabetes, annual screening for albuminuria should begin at puberty or at age >10 years, whichever is earlier, once the youth has had diabetes for 5 years 1

Patients with Reduced Nephron Mass

• In patients with reduced nephron mass, afferent arteriole vasodilation occurs to increase single-nephron GFR, which may impair autoregulation 1
• This can allow transmission of elevated systemic blood pressures to glomerular capillaries, potentially causing barotrauma 1
• ACE inhibitors and ARBs are particularly beneficial in this population as they help reduce intraglomerular pressure 1

Monitoring Considerations

• When using eGFR to monitor kidney function, consider that creatinine-based estimates may be less accurate in patients with extreme body composition, severe chronic illness, or other factors affecting creatinine generation 6
• Consider using cystatin C-based eGFR or measured GFR in situations where more accurate assessment is needed for clinical decision-making 1, 6

Potential Pitfalls and Limitations

• An initial decrease in GFR may occur with ACE inhibitors or ARBs but is generally beneficial long-term by reducing intraglomerular pressure 1, 7
• While compensatory glomerular hyperfiltration may maintain kidney function after nephron loss, the associated increased glomerular capillary pressure can contribute to CKD progression 7
• Reversal of hyperfiltration with kidney-protective medications may cause an initial dip in GFR but is associated with better long-term outcomes 7

By implementing these evidence-based strategies, GFR can be optimized and kidney function preserved in patients with or at risk for kidney disease.