Kidney Week

Abstract: FR-PO101

Urinary Waxy Casts Are Associated with Glomerular Etiology of AKI and Greater Risk for AKI Severity and Post-AKI Chronicity

Session Information

• AKI: Diagnosis and Outcomes
  October 25, 2024 | Location: Exhibit Hall, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

• 102 AKI: Clinical, Outcomes, and Trials

Authors

• Lewis, Stephanie K., UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Stephanie K. Lewis

• Varghese, Vipin, University of Michigan Division of Nephrology, Ann Arbor, Michigan, United States

Vipin Varghese, MD

• Punukollu, Pooja Ashley, UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Pooja Ashley Punukollu

• Baguley, Joshua, UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Joshua Baguley

• Kiely, Conor, UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Conor Kiely, MS

• Gerschultz, Jaclyn Rose, UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Jaclyn Rose Gerschultz

• Muhtaseb, Rami N., UQ-Ochsner Clinical School, New Orleans, Louisiana, United States

Rami N. Muhtaseb

• Chalmers, Dustin R., Louisiana State University, Baton Rouge, Louisiana, United States

Dustin R. Chalmers, MD, MS

• Velez, Juan Carlos Q., Ochsner Health, New Orleans, Louisiana, United States

Juan Carlos Q. Velez, MD, FASN

Group or Team Name

• Ochsner Group.

Background

Identification of muddy brown granular casts (MBGC) by microscopic examination of the urinary sediment (uSEDI) has been reported to predict increased acute tubular injury (ATI) severity. Waxy casts have been traditionally linked to chronic kidney disease (CKD). Recent preliminary observations unveiled diagnostic and prognostic value of WxC in acute kidney injury (AKI). We aimed to explore the relationship of AKI phenotype and outcome with identification of WxC, isolated or in combination with MBGC, in an expanded prospectively-generated AKI cohort.

Methods

We conducted a prospective observational study in patients seen for inpatient nephrology consultation with AKI who had uSEDI performed, over a 6-yr period. Presence of >10% of low power fields with MBGC or WxCs was recorded. Outcomes included need for dialysis (AKI-RRT) and acute kidney disease (AKD) [serum creatinine (sCr) >1.5 times baseline sCr] at discharge and at 6 months.

Results

801 patients [median age 60, 42% women] were included. Median sCr was 3.4 (IQR 2.3-4.7) mg/dL. The most common etiology of AKI was ischemic ATI (45%). MBGCs and WxCs were found in 45% and 36%, respectively. In those with WxC, 57% had de novo AKI (no preexisting CKD). Glomerular etiology of AKI accounted for only 4% of cases with MBGC but 13% of those with WxC (p=0.0003). MBGC were associated with increased risk for AKI-RRT [OR: 1.8 (1.4-2.6, p=0.0001)] but not for AKD [OR: 1.3 (0.8-2.0, p=0.28)]. WxCs were associated with increased risk for AKI-RRT [OR: 1.9 (CI 1.4-2.7, p=0.0001)] and AKD [OR: 2.5 (CI 1.4-4.4, p=0.002)]. Presence of both MBGC and WxC was associated with even greater risk for AKI-RRT [OR: 2.6 (1.7-3.9, p=0.0001)] and AKI-RRT at 6 months [OR: 4.8 (1.9-11.9, p=0.0008)].

Conclusion

WxC can be identified in AKI without pre-exisiting CKD and are more commonly found in glomerular disease compared to MBGC. Prognostically, WxC are associated with increased AKD risk, and co-identification of MBGC and WxC are strongly associated with greater risk for AKI-RRT during hospitalization and at 6 months. Further validation of these clinically relevant observations is warranted