The Risk Factors of Febrile Urinary Tract Infection After Ureterorenoscopic Lithotripsy.

We aimed to evaluate the risk factors for febrile urinary tract infection (fUTI) following ureterorenoscopic lithotripsy (URSL) for upper urinary tract stones. We retrospectively reviewed the data of 109 patients with upper urinary tract stones who underwent URSL at our hospital from October 2016 to March 2019. We divided the patients into two groups: those who developed fUTI after URSL (fUTI group) and those who did not (non-fUTI group). The retrospectively collected data, including age, sex, body mass index (BMI), mobility, diabetes mellitus, operative duration, preoperative ureteral stent placement, number of stones, stone diameter, CT value of stone, stone location, preoperative UTI, preoperative urine culture, preoperative pyelonephritis, and stone-free status were compared between the two groups. Postoperative fUTI occurred in three of the 109 patients (2.8%). Comparing the two groups, a significant risk factor for developing fUTI after URSL was a low BMI. However, in our study, only three cases developed fUTI after URSL; thus, a multivariate analysis could not be performed. One of the three cases in which fUTI occurred was accompanied by anorexia nervosa and an extremely low BMI of 11 kg/m². In summary, even though we had only 3 fUTI patients and did not perform multivariate analysis, our data suggested a significant risk factor for developing fUTI was a low BMI. Increasing the sample size, and further study seem desirable.