小柯机器人

英国伦敦圣乔治大学Mohammed T Hudda团队对19个国家儿童和青少年无脂体重预测模型进行了外部验证。2022年9月21日出版的《英国医学杂志》发表了这项成果。

为了评估基于英国的预测模型在非英国环境中估算儿童和青少年无脂体重（以及间接脂肪体重）的性能，研究组在19个国家招募了5693名4至15岁的儿童和青少年（49.7%为男孩），拥有英国模型中预测因子（体重、身高、年龄、性别和族裔）的完整数据，以及独立评估的结果测量（通过氘稀释评估确定的无脂体重），对这些个体参与者的数据进行荟萃分析。基于英国预测模型的结果为自然对数转化无脂体重（lnFFM）。对19个国家的R²、校准斜率、大校准和均方根误差的预测性能统计数据进行评估，然后通过随机效应荟萃分析进行汇总。还导出了每个国家的校准图，包括灵活的校准曲线。

该模型在非英国儿童和青少年人群中显示出良好的预测能力，在所有国家中R²值>75%，在19个国家的11个中R²值>90%，并且观察值和预测值具有良好的校准（即一致性）。在19个设置的17个中，均方根误差值（在无脂体重秤上）小于4 kg。R²、校准斜率和大规模校准的合并值分别为88.7%、0.98和0.01。

R²和校准值在不同设置的大范围校准值中明显存在异质性，但在校准斜率中不存在异质性。在男孩和女孩、年龄、族裔和不同国民收入群体之间，该模型表现没有显著差异。为了进一步提高预测的准确性，研究组根据每种设置下的截距重新校准了模型方程，以便将来可使用特定国家的方程。

研究结果表明，基于英国的预测模型和现成的测量结果，在一系列非英国环境中，对儿童无脂体重以及由此产生的脂肪体重进行了预测，这些非英国环境解释了所观察到的无脂体重的很大一部分变异性，并表现出良好的校准性能，特别是在重新校准每个人群的截距后。该模型在4-15岁健康儿童和青少年的中低收入和高收入人群中都具有良好的通用性。

附：原文原文

Title: External validation of a prediction model for estimating fat mass in children and adolescents in 19 countries: individual participant data meta-analysis

Author: Mohammed T Hudda, Jonathan C K Wells, Linda S Adair, Jose R A Alvero-Cruz, Maxine N Ashby-Thompson, Martha N Ballesteros-Vásquez, Jesus Barrera-Exposito, Benjamin Caballero, Elvis A Carnero, Geoff J Cleghorn, Peter S W Davies, Malgorzata Desmond, Delan Devakumar, Dympna Gallagher, Elvia V Guerrero-Alcocer, Ferdinand Haschke, Mary Horlick, Houda Ben Jemaa, Ashraful I Khan, Amani Mankai, Makama A Monyeki, Hilde L Nashandi, Luis Ortiz-Hernandez, Guy Plasqui, Felipe F Reichert, Alma E Robles-Sardin, Elaine Rush, Roman J Shypailo, Jakub G Sobiecki, Gill A ten Hoor, Jesús Valdés, V Pujitha Wickramasinghe, William W Wong, Richard D Riley, Christopher G Owen, Peter H Whincup, Claire M Nightingale

Issue&Volume: 2022/09/21

Abstract:

Objective To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings.

Design Individual participant data meta-analysis.

Setting 19 countries.

Participants 5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment).

Main outcome measures The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R2, calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves.

Results The model showed good predictive ability in non-UK populations of children and adolescents, providing R2 values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were <4 kg in 17 of the 19 settings. Pooled values (95% confidence intervals) of R2, calibration slope, and calibration-in-the-large were 88.7% (85.9% to 91.4%), 0.98 (0.97 to 1.00), and 0.01 (0.02 to 0.04), respectively. Heterogeneity was evident in the R2 and calibration-in-the-large values across settings, but not in the calibration slope. Model performance did not vary markedly between boys and girls, age, ethnicity, and national income groups. To further improve the accuracy of the predictions, the model equation was recalibrated for the intercept in each setting so that country specific equations are available for future use.

Conclusion The UK based prediction model, which is based on readily available measures, provides predictions of childhood fat-free mass, and hence fat mass, in a range of non-UK settings that explain a large proportion of the variability in observed fat-free mass, and exhibit good calibration performance, especially after recalibration of the intercept for each population. The model demonstrates good generalisability in both low-middle income and high income populations of healthy children and adolescents aged 4-15 years.

DOI: 10.1136/bmj-2022-071185

Source: https://www.bmj.com/content/378/bmj-2022-071185

BMJ-British Medical Journal:《英国医学杂志》，创刊于1840年。隶属于BMJ出版集团，最新IF：93.333
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