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Monday, 23 May 2016 08:44

Clinical Research: Salivary Urea As A Renal Function Marker In Acute Kidney Injury

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image caline silvaName: Viviane Calice da Silva

Hospital / Affiliation: Pro-Kidney Foundation, Joinville, Brazil and School of Medicine, Pontifícia Universidade Católica do Paraná, Curitiba, Brazil

Home Country: Brazil

Host Country: USA, Malawi- Africa

Year: 2014

Status of your program: GRANT ACCEPTED

 

 

Title of the project: 

Salivary Urea As A Renal Function Marker In Acute Kidney Injury

Topic: 

Acute Kidney Injury

 

Short description of the project or abstract:

Acute kidney injury (AKI) is very common worldwide, causing high morbidity and mortality, particularly in the developing world. Currently, simple, inexpensive and fast tools to help in the diagnosis and guide treatment are lacking. Salivary urea nitrogen (SUN) dipstick has been proposed as a bedside, screening method to detect AKI. The aim of this project was to evaluate the diagnostic performance of SUN (compared to current standard methods), to diagnose and monitor patients suffering from AKI in different settings around the world. We measured SUN and blood urea nitrogen (BUN) in hospitalized patients diagnosed with AKI based on AKIN and KDIGO-criteria. Patients evaluated in a cross sectional fashion (study 1) and were followed up for 7 days with daily (or every other day) (studies 2 and 3) blood and saliva measurements.
After collection, saliva was transferred to a colorimetric SUN dipstick (Integrated Biomedical Technology, IN). The resultant test-pad color was compared to six standardized color fields indicating SUN of 5–14, 15–24, 25–34, 35–54, 55–74, and ≥75 mg/dL, respectively. BUN was determined by the urease method. AKI was stratified according to the AKIN or KDIGO classification. The diagnostic performance and agreement to severity of AKI were studied in all 3 population across studies using a standardized statistical approach: Bland-Altman analysis and linear mixed effects models to test agreement between SUN and BUN and receiver operating characteristics (ROC) statistics were used to test the diagnostic performance to diagnose AKI severity.

Two hundred fourteen patients were enrolled in the 3 studies, 44 in the cross-sectional analysis and 170 in the follow up study (40 Brazil + USA and 130 Malawi, Africa). SUN and BUN had a good agreement (Spearman rank Rs = 0.69; p<0.001). Diagnostic performance of SUN to diagnose AKI stage 3 was: AUC ROC 0.90 (95% CI 0.80-1.0) (Study 1) and AUC 0.81 (95% CI 0.63 to 0.98) (Study 2) and to diagnose AKI all stages AUC 0.82 (95% CI 0.78–0.87) (Study 3). These results were comparable to the BUN findings: AUC ROC 0.90 (95% CI 0.77-1.0) (Study 1), AUC 0.85 (95% CI 0.71 to 0.98) (Study 2) and AUC 0.82 (95% CI 0.59–1.0)(Study 3). BUN is underestimated by SUN consistently across studies, populations and days in the follow up, and discriminated with comparable accuracy. 

According to the results presented in summary here, SUN has an equivalent diagnostic performance compared to BUN to detect AKI, particularly in the most severe presentations. Even though SUN underestimates BUN, SUN reliably reflects BUN and follows its changes over time. Therefore, SUN testing associated with a thorough clinical evaluation may assist in the identification of patients with suspected AKI, especially under circumstances of limited health care resources and in the most remote settings. The next steps are to analyze the data collected in Angola regarding AKI in patients suffering from Malaria and also start the project application in children with AKI which is intend to start in the second semester of 2016.

 

Learning or Research objectives:

The aim of this project is to evaluate the diagnostic performance of SUN (compared to current standard methods), to diagnose and monitor patients suffering from AKI in different settings around the world, especially under circumstances of limited health care resources.

 

Additional Info

  • Year: 2014
  • Status: Grant accepted
  • Partners: ISN only
  • Region: Latin America and the Caribbean
  • Country: Brazil
  • Topics: AKI
Read 7276 times Last modified on Friday, 17 February 2017 12:25

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