J Korean Soc Emerg Med.  2021 Jun;32(3):242-248.

Association between measurement time of fractional excretion rate of sodium and mid-long term clinical prognosis in acute kidney injury patients

• Kim TH
• Choi HS
• Park SS
• Lee JG
• Ryu HS
• Min DK

Abstract

Objective
Rapid identification of the cause for acute kidney injury (AKI) is very crucial. Among the diagnostic indicators of AKI, the fractional excretion rate of sodium (FENa) is clinically considered the most useful indicator. Numerous studies have reported that rapid identification and treatment of AKI improves the short-term clinical prognosis of AKI patients. However, insufficient studies have reported on the benefits of early assessment of FENa to help improve the mid-long term clinical prognosis of AKI patients.
Methods
We analyzed the timing of FENa in AKI patients who were admitted through our hospital emergency department, over a period of 3 years. The experimental groups are divided into the early group, measuring FENa within 3 hours after arrival in the emergency room, and the late group, measuring FENa later than 3 hours after arrival in the emergency room. The prognostic outcomes determined are major adverse kidney events (MAKE), including new dialysis, deterioration of kidney function to chronic kidney disease (CKD), and death, as well as MAKE and AKI recurrence (MAKER).
Results
Significant differences were obtained between the early group and late group in time taken to start fluid resuscitation (P=0.001), intermittent hemodialysis (P=0.005), and continuous renal replacement therapy (P=0.016), as well as in the mid-long term clinical prognosis of new dialysis (P=0.018) and deterioration of kidney function to CKD (P=0.004). Differences between early group and late group in MAKE (P<0.001) and MAKER (P<0.001) were also statistically significant. In the mid-long term clinical prognosis of death (P=0.706) and AKI recurrence (P=0.466), no significant differences were obtained between the two groups.
Conclusion
Early measurement of FENa (within 3 hours) for AKI patients visiting the emergency room showed better mid-long term clinical prognosis than patients with delayed FENa measurement.

Keyword

Acute kidney injury; FENa; Mid-long term prognosis