Patients with preoperative asymptomatic pyuria are not prone to develop febrile urinary tract infection after ureteroscopic lithotripsy

Background: This study aimed to evaluate the association of asymptomatic pyuria before ureterorenoscopic lithotripsy (URSL) with postoperative febrile urinary tract infection (UTI). Methods: This observational case–control study identified the patients undergoing URSL for ureteral stones between May 2011 and October 2015. The included patients were classified into two groups: the asymptomatic pyuria group (6–50 white blood cells [WBCs]/high-power field [HPF]) and the non-pyuria group (≤ 5 WBCs/HPF). All data were collected by reviewing medical records. Postoperative outcomes were collected in terms of febrile UTI, emergency visits, and stone-free rate. Results: A total of 232 patients were included, 101 in the pyuria group, 131 in the non-pyuria group. Two (0.9%) patients developed febrile UTI after URSL and 12 (5.2%) patients visited emergency department for URSL-related symptoms. The overall stone-free rate was 90.9%. There was no significant difference between the pyuria and non-pyuria groups regarding febrile UTI, emergency visits, and stone-free rate. Multivariate analysis revealed that pyuria was neither significantly associated with postoperative febrile UTI (OR = 1.03, 95% CI = 0.06–18.10, P = 0.98), nor with emergency visits (OR = 0.48, 95% CI = 0.13–1.85, P = 0.29). Conclusions: Compared to the patients with sterile urine prior to URSL, those with asymptomatic pyuria were not prone to develop febrile UTI after URSL.