Wallis MC, Paramsothy P, Newsome K et al: Incidence of urinary tract infections in newborns with spina bifida—is antibiotic prophylaxis necessary? J Urol 2021; 206: 126.

Patients with spina bifida are at risk for chronic renal insufficiency and even end-stage renal disease. As a result, the primary goal of urological care for these patients is the preservation of renal function. The UMPIRE study arose out of an effort to identify ways to optimize the urologic care for patients with spina bifida, particularly with regards to the preservation of renal function. An iterative protocol was designed and adopted as standard of care among the 9 centers involved.¹ Early findings demonstrated that most patients born with spina bifida have normal renal function at baseline with mild or no hydronephrosis.²

Urinary tract infections (UTIs) are a source of morbidity among infants with spina bifida and these infections may lead to renal scarring. The use of antibiotic prophylaxis is a common strategy for preventing UTIs; however, there have been growing concerns about the use of antibiotic prophylaxis and its efficacy. In addition, the true incidence of UTI in patients with spina bifida has been difficult to establish due to varying definitions of UTI throughout the literature.³

The UMPIRE protocol establishes a strict definition for UTI. It establishes criteria for infants to be placed on clean intermittent catheterization (CIC) only if there was evidence of high residuals in the neonatal period. In addition, it was decided that patients should not be placed on antibiotic prophylaxis in the newborn period. Risk stratification based on reflux status and urodynamic findings at 3 months of age would help determine which patients might benefit most from prophylaxis or starting CIC. This gave us a unique opportunity to identify the incidence of UTI in this population and an opportunity to evaluate risk factors for UTI.

We identified 299 infants enrolled in the study who had followup data for the first 4 months of life. A notable finding was the low incidence of UTI in this patient population; 16% of patients ended up being treated for a UTI, but only 4% of patients had a UTI that met the strict definition of UTI with a positive urinalysis, positive urine culture and at least 2 symptoms. We found that patients who were on CIC and those with hydronephrosis categorized as grades 3 and 4 on the Society of Fetal Urology grading system had a much higher risk of being both treated for a UTI and for having a UTI that met our strict definition.⁴

The fact that patients on CIC had an increased incidence of UTI is not surprising. The hydronephrosis was perhaps a little surprising. Patients born with isolated hydronephrosis are not typically thought of as having an increased risk of UTI, but in this population it is possible that the hydronephrosis may reflect some underlying bladder pathology.

We also looked at reflux status and found a trend toward grades 3–5 being a risk factor, but this did not reach statistical significance among patients who met the strict definition of UTI. This may be due to the low incidence with only 12 of 299 patients having a UTI that met criteria.

These data are helpful to providers caring for young infants with spina bifida who are considering the risks and benefits of antibiotic prophylaxis. The findings suggest that those infants with high-grade hydronephrosis and those who are on CIC may benefit the most from antibiotics. The UMPIRE protocol will continue to withhold prophylaxis in the newborn period as we collect more data. It is our hope that longer-term followup with greater numbers of patients will yield better information on how to best risk-stratify these patients.