Urinary kidney injury molecule-1 levels in renal stone patients.

OBJECTIVE: To study kidney injury molecule-1 (KIM-1) biomarker levels, indicating renal tubular damage, in patients with kidney stones and in those who underwent minimally invasive method stone treatment.

PATIENTS AND METHODS: Sixty patients with renal stones between 10 and 20 mm were included into the present study. Patients who were divided into three cohorts underwent micropercutaneous nephrolithotomy (microperc), retrograde intrarenal stone surgery (RIRS), and percutaneous nephrolithotomy (PNL). Urine samples were obtained from all participants before, 4 h and 14 days after the procedure. In all the samples obtained, urinary KIM-1 and creatinine (Cr) levels were measured and KIM-1/Cr ratios (ng/mg creatinine) were calculated.

RESULTS: Preoperative urine KIM-1/Cr ratio was higher than postoperative 14th day. The bigger the renal stone size, the higher was the ratio (correlation coefficient 0.353, p = 0.006). According to preferred treatment procedure, there was a statistically significant decrease in preoperative and postoperative 4th hour and 14th day urine KIM-1/Cr rates in the RIRS and PNL, yet none in the microperc group (p = 0.010, p = 0.001, p = 0.212, respectively).

CONCLUSION: In renal stone patients, the elevated urine KIM-1/Cr ratio levels increase further according to stone size. KIM-1/Cr ratio is a promising marker might be helpful in monitoring the damage created by stone disease.