How should I interpret a GFR result in the context of a patient with diabetes and hypertension?

In a patient with diabetes and hypertension, interpreting the estimated glomerular filtration rate (eGFR) requires careful consideration of both the eGFR value and the presence of albuminuria, as these factors together determine the risk of adverse outcomes and guide management.

1. Use eGFR and albumin:creatinine ratio (ACR) categories together: The patient's eGFR should be classified into GFR categories (G1 to G5) and their urine albumin excretion into ACR categories (A1 to A3). For example, an eGFR of 50 ml/min/1.73 m² with an ACR of 35 mg/mmol corresponds to CKD category G3aA3, indicating a high risk of progression and cardiovascular events.

2. Confirm reduced eGFR: If the eGFR is less than 60 ml/min/1.73 m², confirm the result by repeating the test within 2 weeks to exclude variability and acute kidney injury.

3. Consider limitations of eGFR: eGFR may be less reliable in certain situations such as extremes of muscle mass, acute illness, or in some ethnic groups. In diabetes and hypertension, these factors should be considered when interpreting results.

4. Monitor proteinuria with urine ACR: In people with diabetes, measuring urine ACR is essential to detect and quantify proteinuria, which is a key marker of kidney damage and risk stratification.

5. Use eGFR and ACR to assess risk and guide management: The combination of eGFR and ACR categories helps estimate the risk of CKD progression, cardiovascular events, and mortality, informing decisions about monitoring frequency, treatment, and referral.