Kidney Week

Abstract: FR-PO944

Associations of Urine Albumin to Protein Ratio With Histopathologic Lesions, Clinicopathologic Diagnoses, and Kidney Disease Progression

Session Information

• CKD: Epidemiology, Risk Factors, Prevention - II
  November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2201 CKD (Non-Dialysis): Epidemiology‚ Risk Factors‚ and Prevention

Authors

• Srivastava, Anand, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States

Anand Srivastava,

• Amodu, Afolarin Ayomide, Boston University School of Medicine, Boston, Massachusetts, United States

Afolarin Ayomide Amodu,

• Liu, Jing, Boston University School of Medicine, Boston, Massachusetts, United States

Jing Liu,

• Verma, Ashish, Boston University School of Medicine, Boston, Massachusetts, United States

Ashish Verma,

• Sarvode Mothi, Suraj, Brigham and Women's Hospital, Boston, Massachusetts, United States

Suraj Sarvode Mothi,

• Palsson, Ragnar, Brigham and Women's Hospital, Boston, Massachusetts, United States

Ragnar Palsson,

• Stillman, Isaac Ely, Beth Israel Deaconess Medical Center, Boston, Massachusetts, United States

Isaac Ely Stillman,

• Kestenbaum, Bryan R., University of Washington School of Medicine, Seattle, Washington, United States

Bryan R. Kestenbaum,

• Waikar, Sushrut S., Boston University School of Medicine, Boston, Massachusetts, United States

Sushrut S. Waikar,

Background

The relative content of urine albumin to other proteins may provide additional information on the site of the kidney lesion. The urine albumin to protein ratio (UAPR) may aid in the differential diagnosis of kidney disease but has not been studied in depth.

Methods

We evaluated the UAPR, UACR, UPCR, in 338 individuals who underwent clinically indicated native kidney biopsies from the Boston Kidney Biopsy Cohort (BKBC) Study and 2288 individuals with common forms of CKD from the Chronic Renal Insufficiency Cohort (CRIC) Study. Two kidney pathologists adjudicated biopsy specimens for semiquantiative scores of histopathology in BKBC. Multivariable linear regression models tested the association of UAPR with histopathologic lesions. We constructed receiver operating characteristic curves to compare the ability of UAPR, UACR, and UPCR to distinguish tubulointerstitial disease from other forms of kidney disease. We compared the performance of the kidney failure risk equation to predict 5-year risk of ESKD from proportional hazards models using UAPR, UACR, and UPCR through a likelihood ratio test.

Results

In BKBC and CRIC, the mean age was 53±17 and 57±11 years, mean baseline eGFR was 54.7±34.9 and 41.9±14.7 ml/min/1.73m², median UPCR was 1.62 [0.6–3.7] and 0.5 [0.2–1.5] g/g creatinine, and median UAPR was 0.69 [0.55–0.77] and 0.50 [0.33–0.67] respectively. More severe chronic glomerular, tubulointerstitial, and vascular lesions were associated with higher UAPR. Inflammation of intact tubulointerstitial area was associated with lower UAPR (Figure 1A). UAPR outperformed UACR and UPCR to discriminate between tubulointerstitial disease and other forms of kidney diseases (Figure 1B). UAPR did not outperform UACR and UPCR as a predictor of kidney failure (Figure 1C).

Conclusion

UAPR may hold promise to identify specific histopathologic lesions and to differentiate tubulointerstitial disease from other forms of kidney disease.