Can dynamic changes in preoperative urinary white blood cells and nitrite predict infectious complications after...

Percutaneous nephrolithotomy (PCNL) frequently encounters postoperative infectious complications, notably fever and urosepsis. Although preoperative urine culture guides antibiotics, delayed reporting hampers timely risk stratification. Urinalysis is simple, cost-effective, and repeatable; however, most existing studies focus on single static measurements and lack systematic evaluation of temporal trends.

To evaluate the association between temporal changes in preoperative urinary white blood cells (uWBC) and nitrite (NIT) and the risk of postoperative fever and urosepsis in patients undergoing PCNL.

We conducted a prospective observational study of 346 culture-positive patients undergoing PCNL (March 2021-July 2025). Urinalysis was performed at admission and on the morning of surgery. All patients received 5-7 days of pathogen-directed intravenous antibiotics before surgery. Patients were classified according to the trend of uWBC and NIT changes between the two tests. Both univariate and multivariate logistic regression models were applied to assess the relationships with postoperative fever and urosepsis, and pre-specified clinical subgroup analyses were conducted.

Postoperative fever and urosepsis occurred in 20.8% (72/346) and 3.2% (11/346) of patients, respectively. Compared with patients whose uWBC decreased or remained negative, those with persistently positive or increased uWBC independently predicted postoperative fever (adjusted OR 1.95-2.62, P < 0.05), with a significant dose-response relationship (P for trend = 0.011). Using persistently negative NIT as the reference, persistently positive NIT independently predicted urosepsis (adjusted OR 7.32, P = 0.012) and postoperative fever (adjusted OR 2.41, P = 0.024). Associations were consistent across clinical subgroups.

Dynamic preoperative urinalysis offers a simple, inexpensive, and reproducible approach to stratify infection risk in culture-positive PCNL candidates; lack of improvement or persistent positivity in uWBC, as well as persistently positive NIT, identifies high-risk patients and supports individualized perioperative management, whereas conversion from NIT-negative to NIT-positive status-an infrequent pattern in our cohort-was not independently predictive of postoperative infectious complications. Incorporating dynamic urinalysis changes with stone burden, diabetes, and other clinical characteristics may facilitate preoperative risk stratification and individualized infection-prevention strategies.