Is a patient's kidney function considered normal after recovery from acute kidney injury (AKI) with improved creatinine and glomerular filtration rate (GFR), and can they take medications as usual?

From the Guidelines

No, a patient's kidney function should not be automatically considered normal after recovery from acute kidney injury (AKI), even with improved creatinine and GFR values, as evidenced by the 2022 study in Diabetes Care 1. Patients who have experienced AKI should not resume all medications as usual without medical guidance. Following AKI, many patients develop chronic kidney disease (CKD) or have residual kidney damage that isn't reflected in standard laboratory tests. Medications that are cleared by the kidneys or potentially nephrotoxic require careful consideration, such as:

• NSAIDs (ibuprofen, naproxen)
• Certain antibiotics (aminoglycosides, vancomycin)
• ACE inhibitors/ARBs, which may need dose adjustments or alternatives, although the 2022 study in Diabetes Care suggests that these medications should not be discontinued for minor increases in serum creatinine (<30%) in the absence of volume depletion 1. Contrast dyes used in imaging studies should be approached cautiously. Patients should maintain regular follow-up with healthcare providers for at least 3-6 months after AKI to monitor kidney function. The kidneys may appear to recover based on laboratory values, but often have reduced functional reserve and are more vulnerable to subsequent injuries, as noted in the 2017 study in Nature Reviews Nephrology 1. This occurs because AKI can cause permanent loss of nephrons and structural changes that compromise long-term kidney health, even when standard tests return to baseline. The 2014 commentary in the American Journal of Kidney Diseases also highlights the importance of drug dosing based on the level of GFR and close monitoring of kidney function in patients taking potentially nephrotoxic medications 1. Therefore, it is crucial for patients who have experienced AKI to work closely with their healthcare providers to manage their medications and monitor their kidney function to prevent further damage and complications.

From the FDA Drug Label

Metformin hydrochloride tablets are contraindicated in patients with an estimated glomerular filtration rate (eGFR) below 30 mL/minute/1.73 m 2. Initiation of metformin hydrochloride tablets in patients with an eGFR between 30 to 45 mL/min/1. 73 m 2 is not recommended.

The patient's kidney function is considered recovered with a creatinine level of 0.90 and a GFR of 114, but this does not necessarily mean their kidneys are back to normal. Key points to consider:

• The patient had a significant acute kidney injury (AKI) with a creatinine level of 2.72 and a GFR of 30.
• Although the patient's kidney function has improved, it is essential to monitor their renal function regularly.
• The patient can likely take medications as usual, but it is crucial to assess the benefit and risk of continuing therapy and monitor for potential adverse effects.
• The FDA drug label recommends obtaining an eGFR at least annually in all patients taking metformin hydrochloride tablets 2 2.

From the Research

Recovery from Acute Kidney Injury (AKI)

• The recovery process after AKI can vary among patients, with some experiencing complete recovery and others partial recovery 3.
• Studies have shown that AKI episodes can accelerate the progression to chronic kidney disease and end-stage renal failure, with a high risk of morbidity and mortality 3, 4.
• The degree of renal recovery from AKI can substantially affect long-term endpoints, such as the risk of chronic kidney disease and cardiovascular events 4.

Kidney Function after Recovery from AKI

• Even if post-discharge kidney function returns to normal, hospital admission with AKI is associated with increased renal progression that persists for up to ten years 5.
• The risk of non-recovery of AKI is higher in patients with age, CKD, comorbidity, higher severity of AKI, and acute disease scores 4.
• Post-discharge follow-up of AKI patients is crucial to diagnose renal impairment and prevent further progression, with serial follow-up measurements of serum creatinine and proteinuria warranted 4.

Medication Use after AKI Recovery

• There is no direct evidence to suggest that patients who have recovered from AKI can take medications as they would normally, without considering their individual kidney function and health status.
• However, studies suggest that measures to promote recovery are similar to those preventing renal harm, and specific interventions promoting repair are still experimental 4.
• Patients with a history of AKI should be closely monitored by their healthcare provider to determine the best course of treatment and medication management, taking into account their individual kidney function and overall health status.

Patterns of AKI Reversal

• Different patterns of AKI reversal have been observed, including early reversal that is sustained through discharge, late reversal after Day 7, early reversal with one or more relapses, and relapsing without recovery 6.
• Outcomes for patients with these phenotypes can vary significantly, with age-adjusted 1-year survival ranging from more than 90% for early reversal to less than 40% for patients never reversing 6.