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.