Are “virtual” paediatric weight estimation studies valid?

INTRODUCTION: “Virtual” studies account for nearly one-third of all published weight estimation articles, but the validity of these virtual studies has never been evaluated. It is important to establish this validity in order to decide whether the results of these studies can be applied to real-world usage. The objectives of this study were to evaluate the accuracy of virtual weight estimates using the Broselow and PAWPER tapes and compare these to actual real-life estimates from the tapes. METHODS: Virtual weights were generated for the Broselow and PAWPER tapes using anthropometric data from a sample of 1385 children for whom actual Broselow and PAWPER tape weights were available. The accuracy of the virtual and real-life estimates was compared against each child’s actual weight. The agreement of the virtual and real estimates was also evaluated. RESULTS: The percentage of weight estimates within 10% of actual weight were 57.9% and 59.3% for the real and virtual Broselow tapes respectively and 76.6% and 78.4% for the real and virtual PAWPER tapes respectively. The Cohen’s kappa for the real and virtual Broselow and PAWPER tapes was 0.65 and 0.64 respectively, which indicated substantial agreement. CONCLUSIONS: The virtual and real weight estimates had very similar accuracy outcomes for both tapes in this study. However, if virtual studies are used, they should be followed by real-life studies in order to assess the impact of human and patient factor errors on the accuracy of the weight estimation systems.