Translation of clinical prediction rules for febrile children to primary care practice: an observational cohort study

Background Clinical prediction rules (CPRs) to identify children with serious infections lack validation in low-prevalence populations, which hampers their implementation in primary care practice. Aim To evaluate the diagnostic value of published CPRs for febrile children in primary care. Design and setting Observational cohort study among febrile children (< 16 years) who consulted five GP cooperatives (GPCs) in the Netherlands. Method Alarm signs of serious infection and clinical management were extracted from routine clinical practice data and manually recoded with a structured electronic data-entry program. Eight CPRs were selected from literature. CPR-variables were matched with alarm signs and CPRs were applied to the GPC-population. 'Referral to emergency department (ED)' was used as a proxy outcome measure for 'serious infection'. CPR performance was assessed by calibration analyses, sensitivity, specificity, and area under the ROC-curve (ROC-area). Results A total of 9794 GPC-contacts were eligible, 54% male, median age 2.3 years (interquartile range 1.0-4.6 years) and 8.1% referred to ED. Frequencies of CPR-variables varied from 0.5% (cyanosis, drowsy) to 25% (temperature = 40 degrees C). Alarm signs frequently included in CPRs were 'ill appearance', 'inconsolable', and 'abnormal circulatory or respiratory signs'. The height of the CPR's predicted risks generally corresponded with being (or not being) referred to the ED in practice. However, calibration-slopes indicated that three CPRs underestimated the risk of serious infection in the GPC-population. Sensitivities ranged from 42% to 54%, specificities from 68% to 89%. ROC-areas ranged from 0.52 to 0.81, with best performance of CPRs for children aged <3 months. Conclusion Published CPRs performed moderately well in the primary out-of-hours care population. Advice is given on how to improve translation of CPRs to primary care practice.