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Abstract: TH-PO074

AKI May Be Underdiagnosed in Children Receiving High-Dose Methotrexate

Session Information

Category: Acute Kidney Injury

  • 102 AKI: Clinical‚ Outcomes‚ and Trials

Authors

  • Mendoza Flores, Brenda, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
  • Clark, Amanda J., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
  • Saade, Marie Christelle, The University of Texas Southwestern Medical Center, Dallas, Texas, United States
  • Parikh, Samir M., The University of Texas Southwestern Medical Center, Dallas, Texas, United States
Background

High-dose methotrexate (HDMTX) is a nephrotoxic therapy given to children with cancer. It is known that every episode of acute kidney injury (AKI) increases the risk of developing chronic kidney disease, making it particularly impactful for children. Current protocols for reducing AKI incidence with HDMTX include hyperhydration, urine monitoring, and serial serum creatinine measurements. It is not well known how hydration affects creatinine interpretation or AKI diagnosis during HDMTX therapy.

Methods

All children admitted to a children's hospital receiving HDMTX as part of routine care in a six month period were enrolled under an IRB approved protocol. Clinical and demographic data were collected from patients’ charts. For each patient, serum creatinine at admission was recorded along with the hyperhydration creatinine nadir. The nadir was determined as the point in which serial urinalyses showed a specific gravity < 1.010 but before HDMTX was given. AKI was defined as a 50% increase above admission creatinine or hydration nadir creatinine based on KDIGO criteria. Data were analyzed using Chi-square and paired t-tests.

Results

In total, 58 admissions for HDMTX were studied representing 19 children aged 2-19. The hydrated nadir creatinine was 15.8% ± 12.6 lower than admission creatinine (Fig1A,p < 0.0001). Based on admission creatinine, 3.45% of HDMTX admissions resulted in AKI. After reclassification using the hydrated nadir, AKI incidence rose to 13.8% (Fig1B-C,p=0.004).

Conclusion

These data highlight the difficulties in using serum creatinine as a marker for renal function, especially in children where modest changes in creatinine imply significant changes in estimated function. Serum creatinine flucuates with fluid status; fluid augmentation with chemotherapy accentuates this limitation. Our data show that children receiving HDMTX may be underdiagnosed with AKI. This could prevent renal protective medication adjustements and limit access to renal-specific follow-up. These data highlight the ongoing need for more sensitive, specific, and timely markers of renal function, specifically in children.

Funding

  • Other NIH Support