Participants
The study participants were part of the Feasibility Trial of the iAmHealthy Intervention for Healthy Weight in Rural Children Recruited from Primary Care Clinics (iAmHealthy; NCT04142034) through Environmental Influences on Child Health Outcomes IDeA States Pediatric Clinical Trials Network (ECHO ISPCTN) sites. Families of children attending four rural primary care clinics who met the following inclusion criteria were invited to participate (one child and one caregiver): ages 6–11 years old, BMI percentile ≥ 85th, household located in a rural area, and child and primary caregiver spoke English. Rurality was defined as United States Department of Agriculture Rural-Urban Commuting Area (RUCA) codes greater than or equal to 4 [13]. Detailed study methods are reported elsewhere [14, 15].
Procedure
The iAmHealthy feasibility trial was initiated in early 2020 with four ISPCTN sites in Nebraska, South Carolina, Delaware, and West Virginia to evaluate feasibility related to participant recruitment, participant retention, intervention dose, and blinding to prepare for a larger randomized controlled trial [16]. The recruitment effort was initiated in February 2020 and was halted on March 13, 2020, due to the onset of the COVID-19 pandemic in the U.S. [17]. The study team amended the study protocol to adapt to pandemic-related research restrictions limiting in-person research contact at participating sites. The changes included switching key outcome measures from in-person to remote collection, including height and weight measurements. The study team followed CDC guidance and prior research on measuring height and weight at home [8, 12] and used a detailed protocol. [11] (see Table 1). The protocol was provided to both caregivers and the study personnel who observed the measurement session and completed in-person measurements. The study team from each site shipped equipment, including a digital scale, measuring tape, painter’s tape, and ruler, to each participating family.
At the post-intervention measurement, two of the four clinics (South Carolina and Delaware) lifted their in-person visit restrictions and allowed participants to have data collected both remotely and in-person, which presented an opportunity for validating the caregiver protocol to measure remote height and weight. All measures for this validation study across both sites were completed between February 8 and March 7, 2021. These protocol changes were approved by the Data Safety and Monitoring Board (DSMB), the National Institutes of Health (NIH), and the University of Arkansas for Medical Sciences Institutional Review Board (central IRB for the study). Written informed consent approved by the central IRB (cIRB #: 249932) and/or child assent were obtained for all participants.
Table 1
Protocol for standardization of measuring height and weight at home through videoconferencing
Instructions for research staff Caregivers and children will measure their height and weight at home with the help of an iAmHealthy study team member. The families will measure their height and weight on a video call with an iAmHealthy study team member. The team member will give the family instructions on how to obtain height/weight and will observe the measurement over the video call to ensure accuracy. The families will report the height and weight to the team member during the video call, and the team member will log it in the study records. Instructions for caregivers Steps to measure your child’s height 1. First, find a flat, uncarpeted section of the floor and a flat section of the wall. 2. Have your child remove their shoes. 3. Remove braids, headbands, or anything else on your head that may get in the way of an accurate measurement. 4. Remove any bulky clothing that may make it difficult to stand flat against the wall. 5. Have your child stand with their feet flat on the floor with their heels against the corner where the wall and floor meet. Make sure their head, shoulders, and buttocks are touching the wall. 6. Have your child stand up straight with their eyes looking straight ahead. Your child’s chin should be parallel to the floor. 7. Place a flat object (like a rule or hardcover book) against the wall at a right angle. Then lower it until it rests gently on top of your child’s head, keeping it at a right angle to the wall. 8. Lightly mark the wall (or a piece of masking tape that you have adhered to the wall) with a pencil at the point the ruler or book (or other flat objects) meets your child’s head. 9. Use a tape measure to measure the distance from the floor to the mark on the wall. 10. Take note of the measurement to the nearest 1/8th of an inch or 0.1 centimeters. Steps to measure you and your child’s weight 1. Place a scale on a flat, uncarpeted floor section. 2. Remove your/your child’s shoes and any heavy objects (jackets, sweatshirts, coats, etc.). Remove items from your pockets (wallet, keys, etc.). 3. If the scale is digital, tap with your foot so the scale turns on. Remove your foot. 1. Once the scale displays “0.0”, have you or your child step on the scale. 2. Hold still for several seconds until the number on the scale stops moving. 3. Take note of the measure to the nearest 0.01 lb. |
Blinded ECHO ISPCTN site assessors completed training for implementing both remote and in-person height and weight measurements. They measured the height and weight of three people at their site following the protocol in Table 1 and reached inter-rater reliability, with less than a 5% difference with a backup-blinded assessor. The site coordinators assessed the clinic stadiometer and scale monthly for reliability and calibrated the equipment before each measurement. Blinded assessors were instructed to complete remote and in-person measurements as close together as possible, in any order.
Remote Measurement Visits via Videoconferencing
The blinded assessors guided caregivers through remote measurements using HIPAA-compliant Zoom (Zoom Video Communications, Inc., San Jose, CA) to observe the measurement and verbally obtain and record the child’s height and weight and caregiver height and weight measurements in triplicate. Caregivers were provided with the measurement protocol in advance of the videoconferencing visit.
In-Person Measurement Visits
The blinded assessors obtained the height and weight measurements in triplicate for both the caregiver and child participants in the two primary care clinics. The measurements were conducted following the same protocol (Table 1).
Measures
Weight
Home scale weights were taken using standardized equipment (Etekcity High Precision Digital Body Weight Bathroom Scale with Ultra-Wide Platform and Easy-to-Read Backlit LCD; model number 025706343039; 440 lb; $26.99), accurate within 0.2 lb. Clinic weights were measured using the SECA Model 813 portable digital scale (SECA, Hamburg, Germany; 440 pounds; $102), accurate within 0.2 lb over a range from 1 to 440 lb. All weights were measured in triplicate, with participants wearing light clothing and no shoes, and were recorded to the nearest 0.01 lb (for home weights) or 0.1 kg (for clinic weights). Mean values were used in the analyses.
Height
Child home height was measured by their caregiver using a tape measure provided by the research team (Amazon Basics Tape Measure, model number DS-TAM10-16ft; $9). Child clinic height was measured on a Detecto Free-Standing Portable Height Rod (4.5 in – 81 in / 11.5 cm – 205 cm: $165). During height measurements, participants were instructed to remove their shoes, stand against the wall, and look straight ahead, following the detailed procedures outlined in Table 1. All heights were taken in triplicate and recorded to the nearest 0.1 cm; the mean of the three measures was used in analyses. The caregiver's height was measured at home in the same manner by another adult following the procedure in Table 1. The caregiver’s self-reported height was recorded when another adult was unavailable.
Demographic Information
Caregivers completed the iAmHealthy Demographics Form at baseline, which contained questions about child and caregiver age, sex, race, ethnicity, household income, insurance status, caregiver education, and zip code (used to determine rurality using RUCA codes).
Data Processing
We calculated BMI in kg/m2 for children and caregivers using the height and weight data collected remotely and in-person. Researchers also calculated the BMI adjusted Z-score (BMIaz) for children to measure childhood adiposity change using methods outlined by Freedman & Berenson [18]. BMIaz is calculated as the BMI z-score adjusted to the 95%ile z-score value for age and gender. BMIaz is designed to be more sensitive to change for children with BMI percentiles over the 97th percentile, especially for those under 10 years of age [18]. Similarly, BMI as a percent of 95%ile value can be employed, and any BMI greater than 120% of the 95%ile is considered severe obesity.
We then calculated the absolute mean difference (i.e., average absolute differences between remote and in-person measurements) and the overall mean difference (i.e., average differences between remote and in-person measurements) for child and caregiver height, weight, BMI, and child BMIaz. As pointed out by Forseth et al. [11], analysis of the average magnitude of differences, regardless of direction, can help us understand the impact of measurement discrepancies on individual-level outcomes.
Data Analysis
Descriptive statistics were calculated for participant sociodemographic characteristics. The mean, standard deviation, and 95% confidence interval (CI) for remote and in-person child and caregiver height, weight, BMI, and child BMIaz were also calculated. All data analyses were carried out with SAS software version 9.4.
Absolute Mean Difference
We used one-sample t-tests to determine if the mean absolute value of the difference between measurements was significantly different from 0. The mean, standard deviation, and 95% CI of the absolute mean difference between approaches for child and caregiver weight, height, and BMI and child BMIaz are reported.
Overall Mean Difference
We used paired samples t-tests to examine within-person differences between remote and in-person child and caregiver weight, height, BMI, and child BMIaz to determine if there were systematic differences, i.e., one measure was consistently higher than the other. The average within-person difference between approaches, its standard deviation, and the 95% CI are reported. The agreement between the remote and in-person measurements was further investigated by examining Bland-Altman plots [19] to estimate the limits of agreement [LOA], or the interval within which 95% of the differences between the two measurements fall and to examine whether the differences between remote versus in-person measurements were consistent across the range of the average values of child and caregiver weight, height, and BMI and child BMIaz measures. Additionally, we computed intraclass correlation coefficients (ICCs) to assess how variability in child and parent height and weight measurements could be attributed to the differences between remote and in-person assessment methods.
Exploratory Analysis
Simple linear regression was used to examine whether child age, sex, ethnicity, race, caregiver education level, or the number of days between measures were associated with the measurement discrepancies in child and caregiver weight, height, BMI, and child BMIaz. Covariates that had a significant relationship with the measurement discrepancies in the simple linear regression models were then included in a multivariable linear regression model.