Abstract: PD12-10
Sources of Funding: The study was partially funded by an unrestricted Internal Research Fund award granted to the investigation team by the Department of Surgery, Schulich School of Medicine & Dentistry._x000D_

Introduction

Newly discovered biomarkers have been used to assess renal function in several clinical situations, and diverse studies have suggested a relationship between urinary tract obstruction and increased levels of these biomarkers. It has been postulated that some inflammatory conditions may affect the expression of these markers precluding its use in our population. We planned to evaluate the urinary levels of Kidney Injury Molecule-1 in a set of urological patients to determine which factors may be associated with its expression._x000D_

Methods

From a prospective observational cohort study, we included patients with hydronephrosis caused by renal stone disease or ureteric stricture, and patients with non-obstructive nephrolithiasis. Demographical, clinical and radiological characteristics were evaluated before and after surgical treatment. Urinary normalized KIM-1 concentration was measured using ELISA analyses in three different occasions, one preoperative and in two postoperative assessments. Non-parametric tests were used to compare KIM-1 levels during follow-up. The presence of stone disease, double J stent and hydronephrosis were noted and dichotomized. Correlations between biomarkers' levels and clinical or radiological characteristics were assessed using Spearman's correlation coefficient.

Results

Forty-eight patients and eleven controls were included in the final analysis. First and second postoperative assessment were performed with a median of 17 days (IQR 9.5) and 59 days (IQR 34) after the surgical procedure. Patients with hydronephrosis showed a higher KIM-1 concentration than no-hydro patients and controls (1.19 vs 0.60 ng/mg creatinine, p=0.002). After analyzing KIM-1 expression in hydronephrosis patients exclusively, we found significantly higher levels at baseline, compared to both postoperative evaluations (p<0.001). KIM-1 showed a weak correlation with age, female gender, BMI, Charlson Comorbidity Index and presence of hydronephrosis (p<0.0001). Although, its expression was not correlated with the estimated glomerular filtration rate, leukocyturia, or presence of stone disease. The distribution of KIM-1 levels amongst patients with non-obstructive stone disease did not significantly change despite the surgical management.

Conclusions

This exploratory study found that urinary KIM-1 expression could potentially be affected by some patients' baseline characteristics. However, our results corroborate that urinary KIM-1 may be a reliable marker of hydronephrosis.

Funding

The study was partially funded by an unrestricted Internal Research Fund award granted to the investigation team by the Department of Surgery, Schulich School of Medicine & Dentistry._x000D_