Determining growth faltering with a tracking score

Abstract

A tracking score for determining growth faltering in children was developed and tested. A graphical method was developed for classifying by visual inspection whether or not a given child had faltered in growth. This method was used to classify all children in a sample of Guatemalan children as to faltering in both weight and length between 9 and 24 months of age; 80 of 345 children had faltered in weight, and 44 of 336 children had faltered in length. The accuracies for determining this faltering of seven versions of the tracking score and that of three other commonly used scores were assessed and compared using ROC curves, the areas under the curves, and two other ways. The other scores tested were the increment score, the residual score, and a growth-curve parameter score. The accuracies of the scores were overall lower for weight than for length. For both weight and length, the growth-curve parameter score had the lowest accuracy, and the tracking score that used an intermediate number of measurements (four in the interval of interest and three in the previous interval) had the highest accuracy. The tracking score has a number of features that make it attractive as an indicator of faltering. It is easy to calculate and interpret, preserves magnitude and direction, incorporates several growth measurements into a single indicator of faltering, gives equal weight to the information in all the measurements used, allows for missing measurements, and can be generalized to include other aspects of growth.

Development and Validation of a Child Report Assessment of Child Food Insecurity and Comparison to Parent Report Assessment

“…16 In general, the large-scale use of a definitive measurement approach is prohibitive due to logistical challenges and the time it takes to obtain each measurement, so the development of reference or field measures is critical to being able to measure a phenomenon efficiently. Our analytical approach of developing and using a definitive classification to establish accuracy has been used successfully for validating measures of growth faltering 17 and household or adult food security. 18−20 In this study, in-depth interviews with children were used as the basis for definitive classification of children as experiencing or not experiencing each of 6 subdomains that comprise child food insecurity.…”

Establishing Validity and Cross-Context Equivalence of Measures and Indicators

“…For indicators such as whether or not a young child has faltered in growth 36 or whether or not a child has experienced food insecurity, 37 T i is binary. For example, children with growth faltering have T i positive and children without growth faltering have T i negative.…”

“…The analysis demonstrated that this measure had superior and excellent accuracy, with areas under the curve > 0.9 for both weight and length. 36 For some subfields, establishing the validity of measures is hampered by a lack of a definitive measure to use as a criterion to compare reference or field measures. Assessment of usual dietary intake, for example, presents many challenges to establishing validity.…”

“…Assessment of usual dietary intake, for example, presents many challenges to establishing validity. 39,40 In some situations, creative strategies can be used to develop definitive measures, as has been done for assessment of growth faltering, 36 child dietary intake, 13 and household or individual food insecurity (discussed below). When a definitive measure is not available for establishing the validity of a reference measure-or a reference measure is not available for establishing the validity of a field measure-then agreement with alternative measures can be established, but not validity.…”

Appropriate Use of Linear Growth Measures to Assess Impact of Interventions on Child Development and Catch-Up Growth

“…Alternatively, longitudinal modeling of linear growth can be used, as has been done to demonstrate evidence of catch-up growth at some ages after bouts of Cryptosporidium parvum infection (50) and diarrhea (51,52). Another possible method that theoretically could be adapted was developed for identifying children in rural Guatemala who faltered in growth during the age of 9-24 mo by comparing growth during this period with that of the previous period (53). This method capitalized on the alignment of the period of growth inhibition for most children as starting at ∼9 mo when children were consuming substantial foods other than human milk and were more exposed to pathogens in their physical environment.…”