Predictors of recurrence and renal scarring post-urinary tract infection among young febrile infants

Q: How is UTI recurrence defined in this study?

Recurrence is defined as any episode occurring within one year of the index UTI.

Q: Which factors independently predicted recurrent UTI in young febrile infants?

Male sex and ultrasound kidney, ureter, and bladder (US KUB) abnormalities independently predicted recurrence.

Q: What factors were associated with renal scarring after UTI?

Renal scarring was associated with bacteraemia, elevated procalcitonin, non-E. coli uropathogens, hydronephrosis, and vesicoureteral reflux, with higher grade severity showing stronger association.

Sep 30, 2026

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Urinary tract infections in infants aged 3 months or younger carry substantial risk of recurrence and renal scarring, yet reliable high-risk markers remain limited. This study retrospectively reviewed febrile infants at a tertiary pediatric hospital and used logistic regression to identify predictors of UTI recurrence and renal scarring. Male sex and abnormal US KUB independently predicted recurrence, while renal scarring correlated with bacteraemia, high procalcitonin, non-E. coli pathogens, hydronephrosis, and vesicoureteral reflux.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

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Abstract

Background

Methods

Results

Conclusion

Background

Epidemiology and risk profile

Diagnosis and risk stratification

Imaging and guideline variability

Tham etal. BMC Pediatrics (2026) 26:20 BMC Pediatrics [https://doi.org/10.1186/s12887-025-06322-z](https://doi.org/10.1186/s12887-025-06322-z) RESEARCH Open Access Predictors of recurrence and renal scarring post-urinary tract infection among young febrile infants Koei WanTham 1,6†, Ian Yi En Ong2,6*†, Hui Chee Tan2,6, Siew Le Chong3, Rupini Piragasam4, Lena Wong4, Zi Xean Khoo5,6, Gene Yong-Kwang Ong2,6, Sashikumar Ganapathy2,6 and Shu-Ling Chong2,6 Abstract Background Urinary tract infections (UTIs) among infants ≤ 3 months old are associated with a high risk of recurrence and renal scarring, yet evidence identifying high-risk infants remains limited. We aimed to identify predictors of UTI recurrence and factors associated with renal scarring in this population. Methods A retrospective chart review was conducted on febrile infants ≤ 3 months at a tertiary paediatric hospital in Singapore, between January 2018 and June 2023. We defined recurrence as any episode occurring within 1 year of the index UTI and renal scarring based on the Technetium-99 m 2,3-dimercapto-succinic-acid (DMSA) scan. Multivariable logistic regression was performed to predict for UTI recurrence and renal scarring, using covariates selected a priori. We presented the adjusted odds ratio (aOR) with corresponding 95% confidence interval (95%CI) . Results Among 401 infants (median age: 49 days [28–70]; 76% male), 49 (12 . 2%) experienced recurrent UTI. Male sex (aOR = 2 . 80, 95%CI:1 .14–8.46, p = 0 . 041) and ultrasound kidney, ureter, and bladder (US KUB) abnormalities (aOR = 2 . 72, 95%CI:1 .40–5. 27, p < 0. 05) independently predicted recurrence. Among 161 infants with DMSA performed, 21 (13 . 0%) developed renal scarring. Scarring was associated with bacteraemia (OR = 4 . 38, 1.54–12. 05, p < 0. 05), elevated procalcitonin ≥ 0.5 ug/L (OR = 16 . 82, 4 .53-109. 39, p < 0. 001), non-E. coli uropathogen (OR = 6 . 18, 2 .37–17.49, p < 0. 001), hydronephrosis (OR = 3 . 04, 1.17–7. 87, p < 0. 05), and vesicoureteral reflux (VUR) (OR = 18 . 70, 4 .31-133. 32, p < 0. 001), particularly high-grade severity ≥ 3 (OR = 25 . 50, 5 .74-185.47, p < 0. 001) . Additionally, multivariable analysis identified USKUB abnormalities (aOR = 3 . 00, 1.57–5. 73, p < 0. 001) as an independent predictor of renal scarring. Conclusion We reported independent predictors of UTI recurrence and risk factors for renal scarring. These patients should receive more intensive monitoring after their index UTI. Keywords Infant, Nephrology, Renal scarring, Risk factors, Urinary tract infection †Koei WanTham and Ian Ong have contributed equally to this work. *Correspondence: Ian Yi En Ong[ian.ong@mohh.com.sg](ian.ong@mohh.com.sg) 1Duke-National University of Singapore (Duke-NUS) Medical School, Singapore, Singapore 2Department of Emergency Medicine, KK Women’s and Children’s Hospital, Singapore, Singapore 3Department of Paediatric Medicine, Nephrology Service, KK Women’sand Children’s Hospital, Singapore, Singapore 4KK Research Centre, KK Women’s and Children’s Hospital, Singapore, Singapore 5Department of Paediatric Medicine, KK Women’s and Children’s Hospital, Singapore, Singapore 6SingHealth-Duke-NUS Paediatrics Academic Medical Centre, Paediatrics Academic Clinical Programme, Duke-NUS Medical School, Singapore, Singapore © The Author(s) 2025. Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Co

FAQs

How is UTI recurrence defined in this study?

Recurrence is defined as any episode occurring within one year of the index UTI.

Which factors independently predicted recurrent UTI in young febrile infants?

Male sex and ultrasound kidney, ureter, and bladder (US KUB) abnormalities independently predicted recurrence.

What factors were associated with renal scarring after UTI?

Renal scarring was associated with bacteraemia, elevated procalcitonin, non-E. coli uropathogens, hydronephrosis, and vesicoureteral reflux, with higher grade severity showing stronger association.

Sep 30, 2026

Upload by jay