Methods: We retrospectively reviewed all initial VCUGs performed at Children's Hospital of Michigan between January and June, 2010. Patients with a prior VCUG or history of VUR were excluded. History of multiple UTIs prior to VCUG was ascertained by the presence of two or more prior positive cultures in the electronic medical record or history of “recurrent UTI” on VCUG requisition form. Remaining patients with a single positive culture or “UTI” on VCUG requisition were categorized as having a single prior UTI. Outcomes assessed were increased rates of VUR or any urologic abnormality on VCUG and abnormality on DMSA scan (renal cortical scar or split function difference >10%). ANOVA and chi-square tests were performed with SPSS.
Results: Two hundred and sixty two patients underwent initial VCUG during this period. Of the 194 with prior infection, 131 had evidence of a single UTI (83 on history alone, 5 on culture alone, 43 on both). The remaining 63 had evidence of recurrent UTI (50 on history, 7 on culture, 6 on both). VUR was detected in 56 (21.3%); urologic abnormality including VUR was detected in 72 (27.4%). A positive documented urine culture did not increase likelihood of VUR (p=0.49) or any VCUG abnormality (p=0.81). History of recurrent UTI also did not increase likelihood of VUR (p=0.11) or any VCUG abnormality (p=0.80). DMSA was performed in 26 and was abnormal in 11 (42.3%). The only predictors of DMSA abnormality were VUR on VCUG (p<0.001) or any VCUG abnormality (p=0.002). DMSA abnormality was not more likely in those with requisition history of UTI (p=0.82) or culture-positive UTI (p=0.18). History of single or recurrent UTI did not increase likelihood of DMSA abnormality (p=0.18). Recurrent UTI also did not increase likelihood of DMSA abnormality (p=0.22).
Conclusions: History of recurrent UTI did not increase the likelihood of VUR or any VCUG abnormality more so than history of single UTI. While this seemingly supports avoiding a VCUG following initial UTI (as the probability of abnormality is no greater), VCUG for recurrent UTI did not lead to increased rates of DMSA abnormalities. These findings support the decision to postpone VCUG until after UTI recurrence, as increased morbidity is not observed. Larger, prospective studies are needed to confirm these preliminary findings.