Rationale Accurate weight measurements are essential for both growth monitoring and drug dose calculations in children. Weight can be accurately measured using calibrated scales in resource-rich settings; however, reliable scales are often not available in resource-poor regions or emergency situations. Current age and/or length/height-based weight-prediction equations tend to overestimate weight because they were developed from Western children's measures.
Objective To determine the accuracy of several proxy measures for children's weight among a predominately HIV-positive group of children aged 18 months to 12 years in Botswana.
Design Weight, length/height, ulna and tibia lengths, mid-upper arm circumference (MUAC) and triceps skinfold were measured on 775 children recruited from Gaborone, Botswana, between 6 July and 24 August 2011.
Results Mean (95% CI) age and weight were 7.8 years (7.5 to 8.4) and 21.7 kg (21.2 to 22.2), respectively. The majority of children were HIV-positive (n=625, 81%) and on antiretroviral treatment (n=594, 95%). The sample was randomly divided; a general linear model was used to develop weight-prediction equations for one half of the sample (n=387), which were then used to predict the weight of the other half (n=388). MUAC and length/height, MUAC and tibia length and MUAC and ulna length most accurately predicted weight, with an adjusted R2 of 0.96, 0.95 and 0.93, respectively. Using MUAC and length/height, MUAC and tibia length and MUAC and ulna length equations, ≥92% of predicted weight fell within 15% of actual weight, compared with <55% using current equations.
Conclusion The development of nomograms using these equations is warranted to allow for rapid and accurate weight prediction from these simple anthropometric measures in HIV-endemic, resource-constrained settings.
- weight prediction
- long bone length
- mid-upper arm circumference
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Contributors Study protocol was developed by RW, MP, GA, SMM, CPL and TJG. Data collection was facilitated by GA, SMM and CPL and conducted by RW and MP. Data analysis was completed by KCW, RW, CDK, ZD and TJG. KCW and RW prepared the initial manuscript under the supervision of TJG and all authors reviewed and revised this work.
Funding This work was supported by the BC Children's Hospital Centre for International Child Health and the University of British Columbia Vitamin Research Fund.
Competing interests None declared.
Patient consent Obtained.
Ethics approval University of British Columbia/Children's and Women's Health Centre of British Columbia Research Ethics Board and the Health Research Development Committee of the Botswana Ministry of Health.
Provenance and peer review Not commissioned; externally peer reviewed.
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