Multichannel urodynamic study (UDS) is a key diagnostic tool for evaluating lower urinary tract function, particularly in patients with neurological deficits or refractory symptoms. Due to its invasive nature, UDS carries a risk of post-procedural urinary tract infections (UTIs), prompting consideration of prophylactic antibiotic use [1]. However, this approach raises concerns about antibiotic overuse and the emergence of resistance. While the Best Practice Policy Statement (BPPS) on Urodynamic Antibiotic Prophylaxis advises against routine prophylaxis in low-risk “index” patients [2], some studies support its use in individuals at higher risk for post-UDS UTIs [3]. Nonetheless, the clinical benefit of prophylactic antibiotics in “non-index” patients—especially those with high-risk characteristics—remains uncertain. This study aims to evaluate whether prophylactic antibiotics reduce the incidence of post-UDS UTIs and to assess their potential protective effect in patients with known high-risk features.

This retrospective cohort study included patients who underwent multichannel UDS at our institution between January and September 2024. Baseline characteristics, history of neurogenic lower urinary tract dysfunction, catheter use, symptomatic UTIs within one year prior to UDS, immunosuppression status, and urodynamic parameters were collected. All UDS procedures were performed in accordance with International Continence Society (ICS) standards. Antibiotic prophylaxis protocols were based on individual clinician judgment but were in principle not applied to the index patient. Post-UDS symptomatic UTI was defined as a new-onset, symptomatic, culture-proven infection occurring within 30 days of the procedure. Post-UDS febrile UTI was defined as UTI with a documented fever >38°C. A history of recurrent UTI was defined as three or more episodes of UTI within 12 months, or two or more episodes within 6 months, occurring within one year prior to the UDS. Chi-square tests, along with univariate and multivariate logistic regression models were used to identify independent risk factors for post-UDS symptomatic UTI. Subgroup analyses were conducted to assess the effect of prophylactic antibiotics in patients with identified high-risk features.

A total of 254 patients were analyzed, including 166 males and 88 females, with a mean age of 64.1±16.5 (SD) years. Prophylactic antibiotics were administered to 113 patients (44.4%), and 32 patients (12.6%) developed post-UDS symptomatic UTIs, including 12 (4.7%) who experienced post-UDS febrile UTIs. There was no significant association between prophylactic antibiotic use and a reduced incidence of either post-UDS symptomatic or febrile UTIs (P = 0.166 and 0.771, respectively). Multivariate analysis identified elevated post-void residual (PVR >100 mL) (OR = 5.73, p < 0.001) and catheter use (OR = 4.96, p < 0.001) as independent risk factors for post-UDS symptomatic UTIs (Table 1). In subgroup analysis, prophylactic antibiotics did not reduce UTI incidence in patients with any of the above risk factors (Table 2).

Our findings partially align with the recommendations of the BPPS, highlighting that patients with elevated PVR, and catheter use are at increased risk of developing post-UDS symptomatic UTIs. However, the other proposed risk factors were not validated in our study. Besides, our study further challenges the role of prophylactic antibiotics in this setting, as their use did not reduce the incidence of either symptomatic or febrile UTIs, even among patients with high-risk features.

Elevated PVR and catheter use are significant risk factors for post-UDS infections. Prophylactic antibiotics did not demonstrate protective efficacy, even in patients with high-risk features.

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Cameron AP, Campeau L, Brucker BM, et al. Best practice policy statement on urodynamic antibiotic prophylaxis in the non-index patient. Neurourol Urodyn. 2017;36(4):915-926. doi:10.1002/nau.23253
Fox C, Kim MJ, Kuo YH, Fromer DL. Validation of the best practice policy statement on urodynamic antibiotic prophylaxis for the high-risk patient in the era of antibiotic stewardship. Neurourol Urodyn. 2020;39(8):2246-2252. doi:10.1002/nau.24478