How should I manage a patient with an estimated glomerular filtration rate of about 101 mL/min/1.73 m² and a urine albumin‑creatinine ratio of about 153 mg/g who is currently taking losartan 50 mg daily?

Management of Albuminuria with Normal GFR in a Patient on Losartan 50mg

You should add an SGLT2 inhibitor to this patient's regimen and consider uptitrating the losartan dose to 100mg daily. This patient has moderately increased albuminuria (ACR 153 mg/g, which falls in the A2 category: 30-300 mg/g) with preserved kidney function (eGFR 101 mL/min/1.73 m²), indicating early diabetic kidney disease that requires intensified therapy to prevent progression 1.

Risk Stratification and Monitoring Frequency

• With an eGFR >90 mL/min/1.73 m² and ACR 30-300 mg/g (A2 category), this patient is in the yellow zone of the KDIGO risk grid, indicating moderate risk for CKD progression and cardiovascular events 1.
• Monitor kidney function and albuminuria at least annually (yellow zone recommendation), though some guidelines suggest twice-yearly monitoring when albuminuria is present 1.
• The current losartan dose of 50mg daily is suboptimal; the RENAAL trial demonstrated that 72% of patients required uptitration to 100mg daily to achieve adequate blood pressure control and maximal renoprotective effects 2.

Primary Therapeutic Intervention: Add SGLT2 Inhibitor

The most important intervention is adding an SGLT2 inhibitor, which has become the cornerstone of diabetic kidney disease management even at this early stage 1.

• SGLT2 inhibitors are recommended for patients with type 2 diabetes and eGFR ≥20 mL/min/1.73 m² when ACR is in the range of normal to 200 mg/g (this patient's ACR of 153 mg/g qualifies) 1.
• These agents reduce CKD progression and cardiovascular events with a Class A recommendation (strongest evidence level) 1.
• SGLT2 inhibitors work independently of blood pressure control and provide benefits beyond what ACE inhibitors or ARBs alone can achieve 1.

Secondary Intervention: Optimize RAS Blockade

Uptitrate losartan from 50mg to 100mg daily unless contraindicated by hypotension or hyperkalemia 2.

• The FDA label for losartan in diabetic nephropathy specifies that most patients (72%) required the 100mg dose to achieve optimal outcomes in the RENAAL trial 2.
• Do not add an ACE inhibitor to the ARB—dual RAS blockade is explicitly not recommended due to increased risk of hyperkalemia and acute kidney injury without additional benefit 1.
• Monitor serum creatinine and potassium within 1-2 weeks after uptitration; do not discontinue losartan for creatinine increases ≤30% in the absence of volume depletion 1.

Additional Therapeutic Considerations

Nonsteroidal Mineralocorticoid Receptor Antagonist (MRA)

• Consider adding finerenone (a nonsteroidal MRA) if the patient remains at high cardiovascular risk or if albuminuria persists despite SGLT2 inhibitor and optimized ARB therapy 1.
• Finerenone is recommended for patients with CKD and albuminuria who are at increased risk for cardiovascular events or CKD progression 1.
• This agent requires eGFR ≥25 mL/min/1.73 m² and careful potassium monitoring 1.

GLP-1 Receptor Agonist

• A GLP-1 agonist should be considered for additional cardiovascular risk reduction if the patient has type 2 diabetes, as these agents reduce albuminuria progression and cardiovascular events 1.
• GLP-1 agonists can be used at any level of kidney function without dose adjustment (except exenatide, which requires caution below eGFR 30) 1.

Target for Albuminuria Reduction

Aim for at least a 30% reduction in ACR from baseline (target <107 mg/g from current 153 mg/g) to slow CKD progression 1.

• This target is based on evidence that a ≥30% reduction in albuminuria correlates with slower decline in kidney function 1.
• Recheck ACR in 3-6 months after initiating SGLT2 inhibitor and uptitrating losartan to assess treatment response 1.
• Two of three specimens should show elevated ACR before confirming persistent albuminuria, due to biological variability 1.

Blood Pressure Management

Target blood pressure of 140/90 mmHg is appropriate for this patient 1.

• The Canadian Society of Nephrology recommends against more aggressive targets (<130/80 mmHg) in the absence of strong evidence for benefit 1.
• Current blood pressure should be optimized with the increased losartan dose before adding additional antihypertensive agents 1.

Glycemic Control Optimization

Optimize glucose control to reduce risk of CKD progression (Class A recommendation) 1.

• Hemoglobin A1c targets should be individualized, but tighter control early in the disease course reduces microvascular complications 1.
• The addition of an SGLT2 inhibitor will provide both glycemic and renoprotective benefits 1.

Dietary Modifications

Sodium restriction to <3.3 g/day (not the more aggressive <2 g/day) is recommended only if the patient has high baseline sodium intake 1.

• Protein restriction is NOT routinely recommended at this stage of kidney function (eGFR >60 mL/min/1.73 m²) 1.
• Protein restriction to 0.8 g/kg/day is reserved for stage 3 CKD or higher (eGFR <60 mL/min/1.73 m²) 1.

When to Refer to Nephrology

Nephrology referral is NOT yet indicated for this patient based on current kidney function 1.

• Referral thresholds include: eGFR <30 mL/min/1.73 m², ACR >60 mg/mmol (approximately >530 mg/g), or continuously increasing albuminuria despite treatment 1.
• Promptly refer if albuminuria worsens despite optimal medical therapy or if eGFR begins to decline rapidly 1.

Common Pitfalls to Avoid

• Do not withhold RAS blockade based solely on the "normal" ACR threshold of <30 mg/g; this patient clearly has albuminuria requiring treatment 1.
• Do not delay SGLT2 inhibitor initiation until kidney function declines further; early intervention prevents progression 1.
• Do not combine ACE inhibitor with ARB; this increases harm without benefit 1.
• Do not discontinue losartan for minor creatinine increases (<30% rise) unless volume depletion is present 1.
• Do not restrict protein intake at this level of kidney function; it provides no benefit and may cause malnutrition 1.