Impact of ARBs on Kidney Function and Cystatin C Levels

Mechanism of ARBs and Kidney Function Parameters

The American Diabetes Association and the National Kidney Foundation recommend ARBs for patients with diabetes, hypertension, and albuminuria to slow CKD progression, primarily affecting albumin excretion rather than filtration markers like cystatin C 2, 1
The American College of Cardiology suggests that ARBs like irbesartan and losartan have demonstrated effectiveness in slowing kidney disease progression compared to other antihypertensive classes in patients with type 2 diabetes and albuminuria 3
Clinical trials have shown that ARBs can reduce the risk of progression to severely increased albuminuria and doubling of serum creatinine, with a moderate strength of evidence 1

Cystatin C is a low-molecular-weight protein produced at a constant rate by all nucleated cells and is freely filtered by the glomerulus, making it a reliable biomarker for kidney function 4
The Kidney Disease: Improving Global Outcomes (KDIGO) guidelines focus on using eGFR (based on creatinine and/or cystatin C) and albuminuria for CKD assessment rather than cystatin C alone, with a high strength of evidence 2, 5
When monitoring kidney function in patients on ARB therapy, clinicians should focus on changes in serum creatinine, eGFR, and albuminuria rather than cystatin C levels, according to the American Heart Association 2, 5

In patients with advanced CKD (eGFR <30 mL/min/1.73 m²), ARBs have demonstrated benefits on mortality and slowed CKD progression despite potential initial changes in filtration markers, with a moderate strength of evidence 2
The combination of ACE inhibitors and ARBs should be avoided due to increased risk of adverse events (hyperkalemia and/or acute kidney injury) without additional benefits on CVD or CKD outcomes, according to the European Society of Cardiology 2, 5
Regular monitoring of kidney function (including serum creatinine and potassium) is essential when initiating or adjusting ARB therapy, as recommended by the National Institute of Diabetes and Digestive and Kidney Diseases 4