How can an adult patient with diabetes or hypertension increase their kidney function?

How to Increase Kidney Function in Diabetic or Hypertensive Patients

You cannot truly "increase" kidney function once it has declined, but you can slow progression and preserve remaining function through aggressive blood pressure control, RAAS inhibition, glycemic optimization, and lifestyle modification. 1

Blood Pressure Control: The Most Critical Intervention

Target blood pressure ≤130/80 mmHg if albuminuria ≥30 mg/24 hours, or ≤140/90 mmHg if albuminuria <30 mg/24 hours. 1

• Aggressive blood pressure reduction is the single most important determinant of slowing GFR decline in diabetic nephropathy 2
• Each 10 mmHg decrease in systolic blood pressure reduces diabetes-related mortality by 15% and microvascular complications by 13% 2
• Most patients will require 3-4 antihypertensive medications to achieve target blood pressure 2
• Both systolic and diastolic hypertension markedly accelerate progression of diabetic nephropathy 1

RAAS Inhibition: First-Line Pharmacotherapy

Initiate an ACE inhibitor or ARB in all diabetic/hypertensive patients with albuminuria ≥30 mg/g creatinine, and titrate to the maximum tolerated dose. 1

• ACE inhibitors and ARBs slow progression of kidney disease independent of their blood pressure-lowering effects 1
• For type 1 diabetes with nephropathy, ACE inhibitors reduce the risk of death, dialysis, and transplantation by 50% 1
• For type 2 diabetes with overt nephropathy (albuminuria >300 mg/24 hours), ARBs are strongly recommended 1, 3
• Monitor serum creatinine and potassium within 2-4 weeks of initiation or dose change 1
• A transient creatinine rise of 10-30% after starting RAAS inhibitors is expected and represents hemodynamic changes, not structural damage 2
• Do not discontinue ACE inhibitor/ARB unless creatinine rises >30% or severe hyperkalemia develops 2
• Never combine ACE inhibitors with ARBs—this is harmful 1

Glycemic Control: Target HbA1c ≤7%

Optimize glucose control aggressively, as hyperglycemia directly accelerates renal function decline. 2, 1

• Strict glucose control reduces the risk of developing albuminuria in diabetic patients 1
• Consider SGLT2 inhibitors for patients with diabetic kidney disease and eGFR ≥20 mL/min/1.73 m², as they slow renal function decline and provide cardiovascular protection 3, 4
• SGLT2 inhibitors correct glomerular hyperfiltration by increasing sodium delivery to the macula densa, causing afferent arteriole constriction 4

Lifestyle Modifications: Non-Negotiable Components

Reduce sodium intake to <2 grams per day, achieve BMI 20-25 kg/m², quit smoking, and exercise 30 minutes five times weekly. 1, 2

• Sodium restriction improves blood pressure control and reduces proteinuria 2
• Normal weight is associated with a 51% lower risk of hypertension in diabetic patients (OR=0.49) 5
• Regular physical activity reduces hypertension risk by 21% (OR=0.79) 5
• An optimal lifestyle in diabetic patients can reduce hypertension prevalence to levels comparable with non-diabetics 5
• Smoking cessation is essential—tobacco use accelerates CKD progression 1

Dietary Protein Restriction

Limit protein intake to 0.8 g/kg body weight/day once overt nephropathy develops, with consideration of further restriction to 0.6 g/kg/day if GFR begins to fall. 1, 2

• Protein restriction reduces hyperfiltration and intraglomerular pressure 1
• Work with a registered dietitian familiar with diabetic dietary management to prevent nutritional deficiency 1

Avoid Nephrotoxins

Immediately discontinue NSAIDs, avoid radiocontrast media when possible, and carefully hydrate before unavoidable contrast procedures. 2

• NSAIDs are particularly nephrotoxic in diabetic nephropathy and CKD 2
• Radiocontrast media are especially damaging in diabetic nephropathy 1
• Review all medications for drugs that compete with creatinine for tubular secretion or have direct nephrotoxic effects 2

Additional Pharmacotherapy Considerations

Add finerenone (a selective mineralocorticoid receptor antagonist) for patients with CKD and type 2 diabetes already on RAAS blockade to reduce CKD progression and cardiovascular events. 1, 3

• High-intensity statin therapy is recommended for all patients ≥50 years with CKD, regardless of GFR 3
• Non-dihydropyridine calcium channel blockers can reduce albuminuria but have not been shown to reduce GFR decline 1

Monitoring and Specialist Referral

Refer to nephrology when eGFR falls below 60 mL/min/1.73 m², or earlier if there is uncertainty about etiology, resistant hypertension, or rapidly increasing albuminuria. 2, 3

• Recheck creatinine and calculate eGFR within 48-72 hours after any intervention to assess response 2
• Monitor for signs of fluid overload during any hydration attempts, particularly in diabetic patients with underlying cardiac dysfunction 2
• Define progression as both a change in GFR category AND ≥25% decrease in eGFR to avoid misinterpreting small fluctuations 3

Common Pitfalls to Avoid

• Do not aggressively fluid-load patients with advanced CKD who may have impaired sodium and water excretion 2
• Do not stop RAAS inhibitors prematurely for small creatinine elevations—a 10-30% rise is expected and acceptable 2
• Do not use loop diuretics for volume management unless absolutely necessary, as they can paradoxically worsen renal function through hemodynamic insults 2
• Do not delay nephrology referral in patients with eGFR <60 mL/min/1.73 m² 2