Clinical prediction rules for childhood urinary tract infections: a cross-sectional study in ambulatory care

Background: Diagnosing childhood urinary tract infections (UTIs) is challenging. Clinical prediction rules may help to identify children that require urine sampling. However, there is a lack of research to determine the accuracy of the scores in general practice. Aim: To validate clinical prediction rules (UTI Calculator [UTICalc], A Diagnosis of Urinary Tract Infection in Young Children [DUTY], and Gorelick score) for paediatric UTIs in primary care. Design & setting: Post-hoc analysis of a cross-sectional study in 39 general practices and two emergency departments (EDs). The study took place in Belgium from March 2019–March 2020. Method: Physicians recruited acutely ill children aged ≤18 years and sampled urine systematically for culture. Per rule, an apparent validation was performed, and sensitivities and specificities were calculated with 95% confidence intervals (CIs) per threshold in the target group. For the DUTY coefficient-based algorithm, a logistic calibration was performed and the area under the receiver operating characteristic curve (AUC) was calculated with 95% CI. Results: Of 834 children aged ≤18 years recruited, there were 297 children aged <5 years. The UTICalc and Gorelick score had high-to moderate sensitivity and low specificity: UTICalc (≥2%) 75% and 16%, respectively; Gorelick (≥2 variables) 91% and 8%, respectively. In contrast, the DUTY score ≥5 points had low sensitivity (8%) but high specificity (99%). Urine samples would be obtained in 72% versus 38% (UTICalc), 92% versus 38% (Gorelick) or 1% versus 32% (DUTY) of children, compared with routine care. The number of missed infections per score was 1/4 (UTICalc), 2/23 (Gorelick), and 24/26 (DUTY). The UTICalc + dipstick model had high sensitivity and specificity (100% and 91%), resulting in no missed cases and 59% (95% CI = 49% to 68%) of antibiotics prescribed inappropriately. Conclusion: In this study, the UTICalc and Gorelick score were useful for ruling out UTI, but resulted in high urine sampling rates. The DUTY score had low sensitivity, meaning that 92% of UTIs would be missed