What to assess when estimated Glomerular Filtration Rate (eGFR) decreases?

From the Guidelines

When a patient's estimated glomerular filtration rate (eGFR) drops, it is crucial to assess for complications of chronic kidney disease, including elevated blood pressure, volume overload, electrolyte abnormalities, metabolic acidosis, anemia, and metabolic bone disease, as outlined in the 2021 standards of medical care in diabetes 1. To evaluate these complications, healthcare providers should perform a thorough medical and laboratory evaluation, including:

• Blood pressure and weight assessment for elevated blood pressure
• History, physical examination, and weight assessment for volume overload
• Serum electrolyte testing for electrolyte abnormalities
• Serum electrolytes testing for metabolic acidosis
• Hemoglobin and iron testing for anemia
• Serum calcium, phosphate, PTH, and vitamin 25(OH)D testing for metabolic bone disease It is essential to evaluate these complications regularly, with the frequency of evaluation depending on the stage of CKD, ranging from every 6-12 months for stage 3 CKD to every 1-3 months for stage 5 CKD 1. In addition to assessing these complications, healthcare providers should also review the patient's medication list to identify potential nephrotoxic drugs and consider modifying drug dosing for patients with eGFR < 60 mL/min/1.73 m², as recommended by the U.S. Food and Drug Administration (FDA) guidance for the use of metformin in CKD 1. For patients with type 2 diabetes and established CKD, special considerations for the selection of glucose-lowering medications include limitations to available medications when eGFR is diminished and a desire to mitigate high risks of CKD progression, CVD, and hypoglycemia, with metformin being considered the first-line treatment, and SGLT2 inhibitors and GLP-1 RAs being considered for patients who require another drug added to metformin to attain target A1C or cannot use or tolerate metformin 1.

From the Research

Assessment of eGFR Drop

When assessing a drop in estimated Glomerular Filtration Rate (eGFR), several factors should be considered:

• Medication use, particularly nonsteroidal anti-inflammatory drugs (NSAIDs) which can be nephrotoxic and affect kidney function 2, 3, 4
• Analgesia dose prescribing and its impact on eGFR decline 3
• Patient demographics, comorbidity, and baseline chronic kidney disease (CKD) status 3
• Use of renin-angiotensin-system inhibitors and other medications that may interact with NSAIDs 3, 5
• Laboratory implementation and standardized calibration traceability for creatinine methods 6

Potential Causes of eGFR Drop

Potential causes of a drop in eGFR include:

• NSAID use, particularly long-acting NSAIDs such as piroxicam and sulindac 4
• Hypertension treatment intensification, especially in patients treated with angiotensin converting enzyme inhibitors (ACEIs) or angiotensin receptor blockers (ARBs) 5
• Other medications or medical conditions that may affect kidney function

Monitoring and Management

Monitoring and management of eGFR drop may involve:

• Regular assessment of kidney function and eGFR 2, 6
• Adjustment of medication regimens, including NSAIDs and antihypertensive medications 2, 5
• Lifestyle modifications and other interventions to slow CKD progression 6