What is the treatment for a 75-year-old white male with established Autosomal Dominant Polycystic Kidney Disease (ADPKD), impaired renal function (GFR 45-50), and elevated serum creatinine (1.3)?

Treatment for a 75-Year-Old Male with ADPKD, GFR 45-50, and Creatinine 1.3

This patient with CKD G3a should receive comprehensive management focused on blood pressure control with ACE inhibitors or ARBs as first-line therapy, cardiovascular risk reduction, and monitoring for complications—tolvaptan is NOT indicated at this age and GFR level. 1

Blood Pressure Management

ACE inhibitors or ARBs are the mandatory first-line antihypertensive agents for this patient. 1

• Target systolic blood pressure <120 mmHg measured by standardized office BP monitoring, as this patient is ≥50 years old with CKD G3 1
• Implement regular BP monitoring with both office measurements and home BP monitoring to complement office readings 1
• Avoid any combination of ACE inhibitor, ARB, and direct renin inhibitor therapy 1
• Select second-line antihypertensive agents based on individual assessment of benefits and risks if BP target is not achieved 1

CKD Management

General CKD management in ADPKD follows the same principles as other kidney diseases, with specific attention to unique ADPKD features. 1

Cardiovascular Risk Reduction

• Initiate lipid-lowering therapy for primary prevention of cardiovascular disease following KDIGO lipid management guidelines 1
• This is critical given the patient's age and reduced kidney function 1

Anemia Monitoring

• Monitor hemoglobin levels, recognizing that ADPKD patients typically maintain higher hemoglobin compared to other CKD patients due to regional hypoxia driving erythropoietin production 1
• Erythrocytosis (hematocrit >51% or hemoglobin >17 g/dL) may occur, though rarely before kidney failure 1
• If erythrocytosis develops and ACE inhibitor or ARB is contraindicated or ineffective at maximal-tolerated dose, therapeutic phlebotomy is indicated 1

Diabetes Management (if applicable)

• Use metformin when eGFR ≥30 mL/min per 1.73 m² 1
• Do NOT use SGLT2 inhibitors—these are not advised in ADPKD due to lack of evidence 1
• Consider GLP-1 receptor agonist if eGFR <30 mL/min per 1.73 m², when metformin is not tolerated, or when metformin alone provides insufficient glycemic control 1

Why Tolvaptan is NOT Appropriate for This Patient

Tolvaptan is contraindicated in this clinical scenario for multiple reasons:

• The patient is 75 years old—tolvaptan is indicated only for adults at risk of rapidly progressing ADPKD with CKD stages 1-4, and advanced age significantly limits the risk-benefit ratio 2, 3
• At GFR 45-50 (CKD G3a), this patient does not meet criteria for "rapid progression" which requires evidence of declining GFR of 4.4-5.9 mL/min/year or TKV growth rate >5% annually 3
• Tolvaptan carries risk of serious and potentially fatal liver injury, requiring intensive monitoring 2
• The medication causes copious aquaresis with risk of dehydration and hypernatremia, particularly problematic in elderly patients 2
• Treatment must be initiated and restarted only in hospital settings with close sodium monitoring 2

Monitoring for Complications

Urinary Tract Infections

• Do NOT treat asymptomatic bacteriuria 1
• For symptomatic UTIs, obtain urine culture before starting antibiotics and use first-line therapy (nitrofurantoin, trimethoprim-sulfamethoxazole, or fosfomycin) based on local susceptibility patterns 1
• If fever, acute flank pain, elevated WBC >11 × 10⁹/L, or CRP ≥50 mg/L develop, obtain blood cultures and workup for kidney cyst infection 1
• Infected cysts require 4-6 weeks of lipid-soluble antibiotics (trimethoprim-sulfamethoxazole or fluoroquinolone, though fluoroquinolones carry increased risk of tendinopathies and aortic complications) 1

Pain Management

• Investigate any flank, abdominal, or lumbar pain to determine kidney-related etiology 1
• Begin with non-pharmacological and non-invasive interventions 1
• Progress to pharmacological treatment if non-pharmacological measures fail 1
• Reserve invasive procedures (cyst aspiration, sclerotherapy, nerve blocks) for refractory cases 1

Intracranial Aneurysm Screening

• Consider screening if the patient has personal history of subarachnoid hemorrhage or family history of intracranial aneurysm, SAH, or unexplained sudden death 1
• Use time-of-flight MR angiography without gadolinium as the screening method 1

Lifestyle Modifications

Implement these evidence-based lifestyle interventions:

• Encourage moderate-intensity physical activity for at least 150 minutes per week plus strength training at least 2 sessions per week 1
• Advise about possibility of direct kidney injury during physical activity given enlarged kidneys 1
• Ensure complete tobacco cessation 1
• Limit alcohol to ≤2 drinks per day for males 1
• Avoid excessive caffeine intake 1
• Provide individualized nutritional counseling, particularly important at CKD G3 1

Kidney Function Assessment Caveat

Important: Estimated GFR formulas are unreliable in ADPKD patients. 4

• eGFR formulas show approximately 50% bounds of error compared to measured GFR in ADPKD 4
• In 1 out of 4 cases with measured GFR <30 mL/min, eGFR provides estimations above this threshold 4
• Consider measured GFR (iothalamate or similar clearance) for accurate assessment, especially if treatment decisions depend on specific GFR thresholds 4
• This patient's actual GFR may differ significantly from the estimated 45-50 mL/min 4

Future Planning

Begin discussions about kidney replacement therapy options:

• Preemptive living-donor kidney transplantation is the preferred treatment for kidney failure in ADPKD 1
• Peritoneal dialysis should be considered a viable option if dialysis becomes necessary 1
• Native nephrectomy should only be performed for specific indications (severe symptoms, recurrent infections, insufficient space for graft, suspected malignancy) and preferably at time of or after transplantation 1