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Kidney Week

Abstract: FR-PO025

Hospitalized AKI Among Black and White Individuals with CKD: The CRIC Study

Session Information

Category: Acute Kidney Injury

  • 101 AKI: Epidemiology, Risk Factors, and Prevention

Authors

  • Muiru, Anthony N., University of California at San Francisco School of Medicine, San Francisco, California, United States
  • Derebail, Vimal K., University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
  • Liu, Kathleen D., University of California at San Francisco School of Medicine, San Francisco, California, United States
  • Go, Alan S., Kaiser Permanente Northern California, Oakland, California, United States
  • Estrella, Michelle M., University of California, San Francisco and San Francisco VA Medical Center, San Francisco, California, United States
  • Hsu, Chi-yuan, University of California at San Francisco School of Medicine, San Francisco, California, United States
Background

Although black race and APOL1 high-risk genotypes are risk factors for various forms of kidney disease, few studies have rigorously examined whether an independent association of black race and APOL1 genotypes exists for occurrence of hospitalized AKI. Prior studies have not accounted for baseline eGFR and proteinuria levels near the time of AKI and have relied only on diagnostic codes to define AKI.

Methods

We studied black and white participants enrolled in the CRIC Study, a multicenter prospective cohort study of CKD, who had an annual in-person study visit between July 2012-June 2013. The primary outcome was hospitalized AKI in the subsequent 2 years (defined as a ≥50% increase from nadir to peak inpatient serum creatinine). We evaluated the association of race, APOL1 genotype and AKI using multivariable logistic regression.

Results

Among 1,162 eligible CRIC participants, 481 were black with 86 (18%) having a high-risk APOL1 genotype. The overall mean (SD) eGFR was 47 (16) mL/min/1.73m2 and neither eGFR or proteinuria significantly differed by APOL1 risk status (Table).The crude risk of AKI was similar between black and white patients (5.2% vs. 5.3%). After adjusting for eGFR and urine protein-to-creatinine ratio, age, sex, educational attainment, blood pressure, prevalent cardiovascular disease, diabetes and receipt of ACE-I/ARB, there was no significant association of race or APOL1 status with AKI (Table).

Conclusion

Among black and white participants with similar baseline eGFR, neither black race nor APOL1 genotype is significantly associated with subsequent hospitalized AKI.

Baseline characteristics and risk of AKI among CRIC participants by APOL1 status.
CharacteristicWhite
(N=681)
Black/Low-risk APOL1
(0 or 1 allele)
(N=395)
Black/High-risk APOL1
(2 alleles)
(N=86)
Mean (SD) age, yr66 (10)66 (9)62 (12)*
Women, %4255*56*
High school graduate, %9778*83*
Cardiovascular disease, %3746*39
Diabetes mellitus, %4456*42
Receipt of ACE-I/ARB, %636670
eGFR, mL/min/1.73m2, mean (SD)47 (16)47 (18)47 (20)
uPCR, g/g, median (IQR)0.12 (0.06-0.35)0.16 (0.08-0.71)*0.16 (0.07-0.47)
SBP, mmHg, mean (SD)122 (18)133 (22)126 (19)
No. of AKI events, n36223
Unadjusted risk of AKI, % (95% CI)5.3 (3.7-7.2)5.6 (3.5-8.3)3.5 (0.7-9.9)
Adjusted odds ratio of AKI (95% CI)Ref0.94 (0.5-1.8)0.62 (0.18-2.2)

* p<0.05 compared to white patients

Funding

  • NIDDK Support