Long-term consequences of urinary tract infection in Childhood (LUCI): Electronic population-based cohort study

Background: Childhood urinary tract infection (UTI) can cause renal scarring and possibly hypertension, chronic kidney disease (CKD) and end-stage renal failure (ESRF). Previous studies focus on selected populations, with severe illness or underlying risk factors. The risk for most children with UTI is unclear. Aim: Examine the association between childhood UTI and outcomes in an unselected population of children. Design and setting: Retrospective population-based cohort study using linked GP, hospital and microbiology records; Wales, UK. Method: Participants: All children born 2005-2009. Follow-up until 31/12/2017. Exposure: Microbiologically confirmed UTI before age five. Key outcomes: Renal scarring, hypertension, CKD, ESRF. Results: Of 159,201 children, 48.7% female, 11,099 (7%) had UTI. 245 (0.15%) were diagnosed with renal scarring by age seven. Odds of renal scarring were higher in children with UTI (1.24%; adjusted odds ratio 4·60, 95% CI: 3·33 to 6·35). Mean follow-up was 9.53 years. Adjusted hazard ratios (95% CI) were:1·44 (0·84 to 2·46) for hypertension; 1·67 (0·85 to 3·31) CKD; 1·16 (0·56 to 2·37) ESRF. Conclusions: The prevalence of renal scarring in an unselected population of children with UTI is low. Without underlying risk factors, UTI is not associated with CKD, hypertension or ESRF by age 10. Further research with systematic scanning of children’s kidneys including those with less severe UTI and without UTI, is needed to increase certainty of these results, as most children are not scanned. Longer follow-up is needed to establish if UTI, without additional risk factors, is associated with hypertension, CKD or ESRF later in life.