Reliability of routinely collected anthropometric measurements in primary care
Authors: Carsley Sarah , C. Parkin Patricia , Tu Karen , Pullenayegum Eleanor , Persaud Nav , L. Maguire Jonathon , Birken Catherine S. , Lau Eddy , Laupacis Andreas , Salter Michael , Szatmari Peter , Weir Shannon , Anderson Laura N. , Borkhoff Cornelia M. , Dai David W. H. , Kowal Christine , Mason Dalah , Abdurrahman Murtala , Anderson Barbara , Anderson Kelly , Arbess Gordon , Knowles Holly , Kwok Bruce , Lakhoo Sheila , Lam-Antoniades Margarita , Leung Fok-Han , Li Alan , Li Patricia , Loo Jennifer , Louis Joanne , Mahmoud Sarah , Malach Jessica , Male Roy , Mascoll Vashti , Meret Aleks , Moodie Rosemary , Morinis Julia , Nader Maya , Nash Katherine , Naymark Sharon , Owen James , Parry Jane , Peer Michael , Pena Kifi , Perlmutar Marty , Persaud Navindra , Pinto Andrew , Porepa Michelle , Qi Vikky , Ramji Nasreen , Ramji Noor , Rana Jesleen , Raza Danyaal , Rosenthal Alana , Rouleau Katherine , Saunderson Janet , Saxena Rahul , Schiralli Vanna , Sgro Michael , Shepherd Susan , Smiltnieks Barbara , Srikanthan Cinntha , Taylor Carolyn , Turner Suzanne , Uddin Fatima , van den Heuvel Meta , Vaughan Joanne , Weisdorf Thea , Wijayasinghe Sheila , Wong Peter , Wormsbecker Anne , Ying Ethel , Young Elizabeth , Zajdman Michael , Bazeghi Farnaz , Bouchard Vincent , Bustos Marivic , Camacho Charmaine , Dalwadi Dharma , Koroshegyi Christine , Malhi Tarandeep , Thadani Sharon , Thompson Julia , Thompson Laurie , Aglipay Mary , Bayoumi Imaan , Cost Katherine , Eny Karen , Kim Theresa , M. Kinlin Laura , Omand Jessica , Vanderhout Shelley , Vanderloo Leigh 
Published: September 2023

<p><strong>Background</strong></p>
<p>Measuring body mass index (BMI) has been proposed as a method of screening for preventive primary care and population surveillance of childhood obesity. However, the accuracy of routinely collected measurements has been questioned. The purpose of this study was to assess the reliability of height, length and weight measurements collected during well-child visits in primary care relative to trained research personnel.</p>
<p><strong>Methods</strong></p>
<p>A cross-sectional study of measurement reliability was conducted in community pediatric and family medicine primary care practices. Each participating child, ages 0 to 18 years, was measured four consecutive times; twice by a primary care team member (e.g. nurses, practice personnel) and twice by a trained research assistant. Inter- and intra-observer reliability was calculated using the technical error of measurement (TEM), relative TEM (%TEM), and a coefficient of reliability (R).</p>
<p><strong>Results</strong></p>
<p>Six trained research assistants and 16 primary care team members performed measurements in three practices. All %TEM values for intra-observer reliability of length, height, and weight were classified as ‘acceptable’ (< 2%; range 0.19% to 0.70%). Inter-observer reliability was also classified as ‘acceptable’ (< 2%; range 0.36% to 1.03%) for all measurements. Coefficients of reliability (R) were all > 99% for both intra- and inter-observer reliability. Length measurements in children < 2 years had the highest measurement error. There were some significant differences in length intra-observer reliability between observers.</p>
<p><strong>Conclusion</strong></p>
<p>There was agreement between routine measurements and research measurements although there were some differences in length measurement reliability between practice staff and research assistants. These results provide justification for using routinely collected data from selected primary care practices for secondary purposes such as BMI population surveillance and research.</p>