Urodynamic investigation (UDI) is the gold standard for evaluating refractory lower urinary tract symptoms. However, its invasive nature, involving bladder and rectal catheterization, can cause emotional and physical discomfort and side effects. The aim of these secondary analyses from a randomized controlled trial (RCT) assessing artifact susceptibility of water- and air-filled urodynamic systems was to assess discomfort and adverse events (e.g. urinary tract infections (UTI)) of UDI.

From 04/2021-01/2022, 490 patients (40% females) participated in the RCT and underwent UDI. In case of asymptomatic bacteriuria, no antibiotic prophylaxis was given. After removal of the catheters, patients were asked to rate their emotional perception and pain on a numerical rating scale from 0-10, with lower values indicating less discomfort/pain. A follow-up telephone interview was conducted 7-14 days later to assess examination-related adverse events. Chi-square test and logistic regression were used to evaluate associations.

Median overall emotional discomfort and pain were 2 (Q1-Q3: 0-5) and 2 (Q1-Q3: 0-4). Female patients reported stronger emotional discomfort (p=0.004). Pain ratings did not differ significantly between sex (p=0.112). In the follow-up interview, 30% (146/490) reported self-limiting pain with a median intensity of 5 (Q1-Q3: 3.5-6) and a duration of ≤72h in 81% (118/146) and >72h in 19% (28/146) of cases. Increased urgency was found in 18% (90/490) (≤72h: 70% (63/90); >72h: 30% (27/90)). 6% (28/490) of patients developed a UTI. UTI was significantly associated with UTI within the past 12 months (odds ratio (OR) 3.01 95% confidence interval (CI) 1.38-6.58, p=0.006)), asymptomatic bacteriuria at UDI (OR 4.54, 95% CI 1.54-13.41, p=0.006) and higher Charlson-Comorbidity-Index (OR 1.22, 95% CI 1.06-1.4, p=0.005). However, the number of positive urine cultures needed to treat to prevent one UTI was 16 (95% CI 9.6-38.6).  Macroscopic hematuria was present in 8% of patients, with 34% of these patients taking anticoagulants or platelet aggregation inhibitors. Severe adverse events requiring hospitalization were seen in 1% (5/490) with 3 of them being examination related (UTIs) and 2 not examination related.

These results offer a comprehensive insight into patients experiences and outcomes within the study. Female patients reported heightened emotional discomfort, while pain levels remained consistent across genders. Approximately 30% experienced transient pain, with urinary tract infections (UTIs) occurring in 6% of cases. Risk factors for UTIs included previous occurrences, asymptomatic bacteriuria, and higher comorbidity indices.

UDI is a well-tolerated examination with an acceptable rate of short- and medium-term adverse events. Prophylactic antibiotics to reduce post-UDI UTIs do not seem justified.