Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2023 Mar 27;24(1):75.
doi: 10.1186/s12882-023-03118-0.

A low BUN/creatinine ratio predicts histologically confirmed acute interstitial nephritis

López Giacoman Salvador  1 , González Fuentes Carolina  2 , Robles Dávila Jesús  2 , Soto Abraham María Virgilia  3 , Román Acosta Susana  2 , Chávez Íñiguez Jonathan  4 , Salas Pacheco José Luis  5 , Ronco Claudio  6
Affiliations

A low BUN/creatinine ratio predicts histologically confirmed acute interstitial nephritis

López Giacoman Salvador et al. BMC Nephrol. .

Abstract

Introduction: In hospitalized patients with acute renal injury (AKI), acute tubulointerstitial nephritis (AIN) constitutes one of the leading etiologies. The objective of this study was to identify clinical and biochemical variables in patients with AKI associated with kidney biopsy-confirmed AIN.

Methods: For our prospective study, we recruited hospitalized patients aged 18 years and older who were diagnosed with AKI based on biochemical criteria. Prior to enrollment, each patient was assessed with a complete metabolic panel and a kidney biopsy.

Results: The study consisted of 42 patients (with a mean age of 45 years) and equal numbers of male and female patients. Diabetes and hypertension were the main comorbidities. Nineteen patients had histological findings consistent with AIN. There was a correlation between histology and the BUN/creatinine ratio (BCR) (r = -0.57, p = 0.001). The optimal Youden point for classifying AIN via a receiver operating characteristic (ROC) curve analysis was a BCR ≤ 12 (AUC = 0.73, p = 0.024). Additionally, in diagnosing AIN, BCR had a sensitivity of 76%, a specificity of 81%, a positive predictive value of 81%, a negative predictive value of 76%, and OR of 14 (95% CI = 2.6 to 75.7, p = 0.021). In the multivariable analysis, BCR was the sole variable associated with AIN.

Conclusion: A BCR ≤ 12 identifies AIN in patients with AKI. This study is the first to prospectively assess the relationship between renal biopsy results and BCR.

Keywords: Acute interstitial nephritis; Acute kidney injury; BUN; Creatinine.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Flowchart showing the study patient distribution. Forty-two individuals required percutaneous kidney biopsy. In nearly half of AIN patients, the etiology was acute kidney injury. In patients with AIN, the BCR was significantly lower. AIN = acute interstitial nephritis, AKI = acute kidney injury, BCR = BUN/creatinine ratio, FSGS = focal and segmentary glomerulosclerosis
Fig. 2
Fig. 2
Violin plot showing the distribution of the BUN/creatinine ratio (BCR) in patients with acute kidney injury. In the AIN population, the median BCR is grouped at approximately 12
Fig. 3
Fig. 3
The ROC plot shows the optimal Youden point discriminating AIN from non-AIN patients with AKI as having a BCR value of 12. BCR = BUN to creatinine ratio
See this image and copyright information in PMC

References

    1. Perazella MA. Clinical Approach to Diagnosing Acute and Chronic Tubulointerstitial Disease. Adv Chronic Kidney Dis. 2017;24(2):57–63. doi: 10.1053/j.ackd.2016.08.003. - DOI - PubMed
    1. Goicoechea M, Rivera F, López-Gómez JM. Spanish Registry of Glomerulonephritis. Increased prevalence of acute tubulointerstitial nephritis. Nephrol Dial Transplant. 2013;28(1):112–5. doi: 10.1093/ndt/gfs143. - DOI - PubMed
    1. Haas M, Spargo BH, Wit EJ, Meehan SM. Etiologies and outcome of acute renal insufficiency in older adults: a renal biopsy study of 259 cases. Am J Kidney Dis. 2000;35(3):433. doi: 10.1016/S0272-6386(00)70196-X. - DOI - PubMed
    1. Fischer RSB, Vangala C, Truong L, Mandayam S, Chavarria D, Granera Llanes OM, et al. Early detection of acute tubulointerstitial nephritis in the genesis of Mesoamerican nephropathy. Kidney Int. 2018;93(3):681–690. doi: 10.1016/j.kint.2017.09.012. - DOI - PubMed
    1. Praga M, González E. Acute interstitial nephritis. Kidney Int. 2010;77(11):956. doi: 10.1038/ki.2010.89. - DOI - PubMed

Supplementary concepts

LinkOut - more resources