Evaluation of change in oxidative stress in urolithiasis patients following complete stone clearance 

Introduction: Prior studies showed that oxidative stress (OS) is increased in urolithiaois patients. Urinary 8-hydroxy 2- deoxyguanosine (8-OHdG) is a well-established marker of OS, and its levels were elevated in patients with urolithiasis. It is unknown whether this increased OS persists even after stone removal. Objective We aimed to evaluate the change in urinary 8-OHdG levels in urolithiasis patients following complete stone clearance. Design, setting and participants: A prospective pre-post-study design (institute ethics committee: NK/5965/MS/029). Urolithiasis patients undergoing surgery for stone clearance were included. Patients with known comorbidities, malignancy, systemic illnesses, body mass index (BMI) > 30 kg/m 2 , age > 50 years, serum creatinine > 1.5 mg/dl, and incomplete clearance were excluded. Single tertiary care center. Outcome measurements and statistical analysis: Urinary 8-OHdG levels were measured in a 24-hour urine sample using ELISA method preoperatively and post-surgery at three months. Mann- Whitney U test, and Kruskal- Wallis test were applied Results and limitations: Forty patients with a mean age and BMI of 34.65(± 11.02) years and 23.58(± 3.23) kg/m 2 respectively were analysed. There was no significant difference in urinary 8-OHdG levels following stone clearance [25.770(1.47–60.38) µg/g creatinine vs 32.00(6.57- 117.35) µg/g creatinine; p = 0.63]. No significant correlation was found between age; gender; smoking or alcohol consumption; degree of hydronephrosis; or stone burden and urinary 8-OHdG levels. Limitations include a small sample size. Conclusions The baseline OS in urolithiasis patients does not change after complete stone clearance. Whether this persistent OS is responsible for stone recurrence needs to be explored.