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UBC Theses and Dissertations

The evaluation of potential weight-estimation methods in a primarily HIV positive cohort in Botswana for use in resource limited settings Wozniak, Roberta

Abstract

Appropriate drug dosing in children should be calculated based on a child’s weight. In resource constrained settings however, inaccurate drug dosing is common due to the absence of working weight scales. Existing proxies for weight, such as those based on age or height, have been shown to be problematic, especially in populations in developing countries. Long bone measurements in children, such as ulna and tibia lengths, have yet to be studied as surrogate measures for weight. The purpose of this study was 1) to examine the association between weight and a series of proxy anthropometric measurements including height, ulna and tibia lengths, mid-upper arm circumference (MUAC), and triceps skinfolds in a primarily HIV positive population of Botswana children (18 months – 12 years); 2) to determine what percentage of the study population has a predicted weight within 10% of their actual weight; and 3) to determine a simple weight-prediction method that would most accurately predict a child’s weight (18 months – 12 years). This study was a cross-sectional survey carried out in a clinical setting at the Botswana-Baylor Children’s Clinical Centre of Excellence in Gaborone, Botswana. We measured weight, height, mid-upper arm circumference (MUAC), triceps skinfolds, ulna length, and tibia length in 777 children between the ages of 18 months and 12 years. Univariate linear regression and multiple linear regression analysis were performed using SPSS and coefficients of determination (R2) were calculated. Accuracy of the weight-prediction method was defined as having a predicted weight within 10% of the child’s actual weight. The MUAC-Tibia and the MUAC-Ulna weight-prediction models had the highest accuracy for predicting a child’s weight with adjusted R2 values of 0.95 and 0.94, respectively. Of the participants, 82% of weights were predicted to within 10% using the MUAC-Tibia method and 79% using the MUAC-Ulna method. Due to the high degree of accuracy, the MUAC-Tibia or MUAC-Ulna weight-prediction methods could potentially be used to estimate a child’s weight. Studies are needed to confirm these findings in other resource poor settings where there is no access to working scales.

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Attribution 3.0 Unported