Study design, materials and methods
A retrospective research on UDS was performed between March 2015 and January 2018 (490 patients). Patients who had at least 1 month follow-up were included for analysis (358). All patients had UC taken before UDS. UTI risk factors were assessed. Positive UC was defined as > 1000 CFU/ml. Asymptomatic bacteriuria (AB) was defined as a positive UC without UTI symptoms. UTI was defined as a positive urine culture plus UTI symptoms. Patients with negative UC did not receive antibiotic prophylaxis. Patients with AB received 3 takes of antibiotic prophylaxis before the study. We did not perform UDS on patients with UTI. UTI was registered up to 30 days after the UDS. Chi-square test, and logistic regression were used for analyzing predictors of positive UC and UTI after UDS.
Results
Analysis included 358 patients. Mean patient age was 58 (18-92). The univariate analysis, showed that intermittent self-catheterization (54.5%), indwelling catheter (65.4%), recurrent UTI (55.8%) and AB before UDS (38.2%) were risk factors for developing positive UC after UDS (p<0.0001). Neither sex nor diabetes were predictors of positive UC or UTI after UDS.
In the multivariate analysis, all predictive factors for positive UC after UDS such as ISC, indwelling catheter, recurrent UTI and AB remained significative with OR 4.3 (IC 95%: 2,1-8.9), 9.8 (IC 95%: 4-24), 4.2 (IC 95%: 2-8.8) and 1.9 (IC 95%: 1.1-3.6) respectively.
After UDS, only 14 patients (3.9%) with positive UC developed UTI symptoms. We did not find any significant predictors of UTI due to the low incidence of patients with symptoms. All infected patients received oral antibiotics and none required hospitalization.
Interpretation of results
Out of all variable studied, ISC, indwelling catheter, recurrent-UTI and AB before UDS were significant predictors of positive UC after UDS in both uni and multivariate analysis. UTI incidence after UDS was low (3,9%), and infections were indolent.