Validation of the mid-arm-based weight estimation formula (the Cattermole formula) for Korean children.

Background: A mid-arm circumference-based weight estimation formula has recently been proposed. The Cattermole formula, which is suggested for children aged 1-11 years, is calculated as (mid-arm circumference in cm - 10) × 3 kg. The objective of this study was to externally validate the Cattermole formula using a Korean national survey database.

Methods: The data collected from a national survey conducted in 2005 by the Korean Pediatric Society included body weight, height, age and mid-arm circumference. To determine whether the Cattermole formula accurately predicted the actual weights of Korean children, we compared the performance of the Cattermole formula with those of other age-based and height-based weight estimation methods.

Results: A total of 91,147 children aged 1-11 years were assessed for eligibility. The mean age was 5.3 years, and 52.6% of the children were boys. The mean measured weight was 22.4 kg, and the mean mid-arm circumference was 17.9 cm. The Cattermole formula resulted in a mean difference of 1.35 kg and a mean percentage error of 11.5% with 95% limits of agreement of -8.1 to +10.8. A total of 37.9% of the estimates were within 10% of the measured weights.

Conclusion: Across all ages, the Cattermole formula was not more accurate than the other methods. However, in children older than 6 years, the Cattermole formula results were more accurate than those of the age-based formulae with the exception of the Broselow tape.

Clinical Trial Registration: None.