Study design
A single-blind, 18-month follow-up, parallel-group cluster randomized controlled trial with 1:1 allocation ratio will be implemented in Yang County, Shaanxi Province, and Shicheng County, Jiangxi Province, China. This trial was registered on August 29, 2020 in the Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.aspx?proj=60036, registration number: ChiCTR2000037606).
Sample size
Based on previous literature [29], we conservatively hypothesize that the unintentional injury incidence of rural preschoolers aged 3-6 years old in project sites is 30% in the past 18 months. On the basis of a previous report [30], we assume the effect size of the app intervention to be 0.80 (incidence rate ratio) compared to traditional unintentional injury prevention intervention. In addition, we assume an intra-class correlation (ICC) of 0.005 with a cluster size of 150 children per preschool [31], and an allocation ratio of 1:1 between intervention and control groups. Considering extensive strategies will be adopted to increase retention in the study, we assume an attrition rate of 15% for the 18-month follow-up. Given these assumptions, a minimum sample size of 3508 caregivers is needed for the study to achieve a statistical power of 80% at the 0.05 significance level. As many rural preschools have more than 150 children in the study sites we select, 24 preschools will be ample to recruit the needed sample size.
Preschool recruitment
We will recruit participants from 24 preschools in China, 14 in Yang County, Shaanxi Province and 10 in Shicheng County, Jiangxi Province. Only preschools with more than 150 enrolled students will be eligible for this study; almost all preschools in the study sites are this size or larger, therefore the exclusion criteria for preschool size will have minimal impact on generalizability of results.
Each invited preschool will receive an official invitation letter along with relevant materials concerning the study. We will randomly allocate enrolled preschools rather than classes or individuals to the intervention group versus control group to avoid undesirable contamination within the same preschool. Thus, 12 preschools will be randomly allocated to the intervention group and 12 to the control group (Figures 1 and 2).
Participant recruitment
Eligible participants meet the criteria: being the primary caregiver of a preschooler attending the included schools.
Potential participants will be excluded from this study if they meet any of the following criteria: (1) unwilling to participate in this study; (2) do not own a smartphone or cannot operate the app independently; (3) cannot read text messages; or (4) expect to move to another city with their children during the study time period. If an eligible caregiver care for more than one eligible preschooler, we will enroll only the youngest child.
In coordination with local cooperative partners (governmental departments and agencies), we will recruit class teachers and school staff to help coordinate recruitment of study participants in each selected preschool. Those individuals will inform eligible caregivers about the study via multiple existing preschool-family communication channels, such as social media platforms (WeChat or QQ), school apps, printed briefing materials and oral notification. Caregivers who agree to participate will be provided an invitation letter that includes the benefits and responsibilities of participating in this study and instructions to download, install, sign up, log in and use the randomly-assigned app. Moreover, all caregivers who agree to participate will receive a short online guidance video that detailedly introduces basic information about the study and educates the participants on how to utilize the app.
When participants log into the app for the first time, they will be invited to complete the informed consent document online. All consenting participants will then complete the baseline survey, which collects information about unintentional injuries the child experienced in the past 3 months as well as information on socio-demographic characteristics, caregiver’s attitudes, caregiver-reported behaviors surrounding child unintentional injury prevention, and caregiver-reported home environment safety based on the standardized safety checklist over the prior week.
Randomization and blinding
Once recruited, each enrolled preschool will be randomly allocated to a group according to the order of computer-generated random number sequence by an independent (masked) researcher. Group allocation will be masked during data analysis.
Interventions
Both the intervention and control groups will receive routine school-based education from each included preschool plus the app-based education programs. Routine school-based education encompasses health education, including injury prevention, that is performed by preschool teachers. This education is typically based on the suggested course from the Ministry of Education of China and influenced somewhat by the teacher’s knowledge and preferences for teaching injury prevention to children.
The basic framework for child unintentional injury prevention in the app is based on previous theories and research [32]. It comprises four active modules: (1) content learning, including a series of instructional materials to impart basic and practical knowledge and skills; (2) social interaction, consisting of an online forum, online expert consultation opportunities, and locations for users to leave comments that facilitate communication among users and between users and experts; (3) survey and feedback, used for online survey data collection and user’s suggestions, and for experts to reply to user queries; and (4) a personalizing module, allowing users to customize the color scheme of their app and to display the user’s personal learning progress. The four active modules will be identical for both groups during the program and are detailed along with the app design and other functions in a previous publication [32].
The intervention will differ between the intervention and control groups based on the learning contents they receive. The control group will receive a parenting health education program covering topics like pediatric disease risks, childhood nutrition, early childhood development, and child health care. It will exclude any explicit information about unintentional child injury prevention. The intervention group will receive all contents the control group receives plus additional components focused on prevention of common child unintentional injuries in rural areas (e.g., road traffic injury, falls, drowning, suffocation, poisoning, burning, scalding, electric current burns, and other injuries caused by animate or inanimate mechanical forces).
A previous report evaluated a precursor version of this app that was created for urban caregivers [24]. The app has been optimized and refined substantially for this trial to focus on the characteristics and needs of children and families in rural China and to overcome some deficiencies identified in the previous trial. The following specific changes were made:
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Enriched and updated the scenarios of knowledge segments tailored to common situations in rural areas of China;
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increased number and diversified categories of audio recordings (30% vs. 0% of contents in current vs. previous app version), interactive games (20% vs. 3%), cartoons (10% vs. 5%), and videos (10% vs. 6%);
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reduced proportion of short essays with pictures (30% vs 86%), based on user’s feedback;
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increased frequency of dissemination of knowledge segments from 4 times a week to 7 times a week for both groups;
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introduction of new learning approaches (e.g., audio learning and regular online theme activities via the app forum); and
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improved user experience and motivation through upgraded strategies for this app, such as additional online video instruction for using the app, automatic display and interaction with the banner and recommended readings in the app’s homepage, refining online expert consultation and customer service, publishing comments and displaying other users’ comments, and changing the font color in the forum to reduce eye strain.
In addition, the time period of this intervention study will be prolonged for 18 months to demonstrate the long-term effectiveness in reducing injury incidence rate. The previous trial for urban families lasted just 6 months.
All components of the app will be available throughout the study period, ensuring that all users in both groups can retrieve and learn from knowledge segments freely and repeatedly. Except for the differences in the content of the app, the implementation of the app-based intervention will be identical for both groups.
Strategies to enhance engagement
In order to enhance engagement with the app-based intervention, we will adopt an external support strategy. Specifically, with the support of local partners including the local education bureau, health committee, maternal and child health hospital, centers for disease control and prevention, a coordinating group will be established for each enrolled preschool. The coordinating group that is composed of local office staff members of the Non-Government Organization “World Vision”, class teachers, and school staffs of each enrolled preschool, will help study participants solve problems with app use and encourage engagement in the study.
Besides sufficient external support from the coordinating groups, several other strategies will be flexibly implemented to encourage active use of the app and participation in the study. First, in both intervention groups a small amount of app-based reward points will be granted based on the participant’s engagement. The reward points will be exchanged for small gifts such as gift cards to refill mobile phone and data services. Second, participants who log in the app for 7 consecutive days will gain a chance to enter a lottery and win additional reward points. Third, we will provide a small gift to students monthly if their caregivers rank among the top 30 active learners over the past month. Finally, automated reminders will be sent to caregivers if they do not read app-delivered knowledge segments or fail to accomplish online questionnaires. If automated reminders fail, the coordinating group will take other actions to remind the participants such as sending a text or voice message or making a phone call.
Outcome measure
The primary outcome measure will be the incidence rate of unintentional injury among preschoolers in the past 18 months, which will be calculated by combining data from the six follow-up evaluations. We will conduct follow-up evaluations on a quarterly basis (every 3 months) to reduce recall bias in participants remembering children’s minor or moderate injuries [24].
An injury event will be included if it meets any of three criteria [24]: (1) child receives a medical diagnosis or treatment by a doctor or other medical professional following an injury; (2) child receives first aid, takes any injury-related medication, or receives massage or cold/hot compress by a family member, teacher or other non-medical staff following an injury; or (3) child is restricted from school or other activities, or is kept in bed or rest for more than a half-day following an injury. If a caregiver reports that a child experienced more than one unintentional injury event in the past three months, we will record the number of injury events but collect specific information only about the most serious one.
Unintentional injury incidence rate will be calculated as “number of preschoolers newly experiencing unintentional injury events divided by total number of preschoolers×100%”.
We also will consider several secondary outcome measures, including: (1) the caregiver’s attitudes toward child unintentional injury prevention, (2) caregiver-reported supervision behaviors related to child unintentional injury prevention in the last week, and (3) the caregiver-reported home environment safety based on a standardized audit checklist over the last week. All secondary outcome measures are based on previously-published and validated items [24, 33–36]. Table 1 lists all planned survey items, with the final survey questionnaire to be refined through a pilot survey, as detailed below.
Table 1
Survey items assessing child caregiver’s attitudes, supervising behaviors, and child home environment safety
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1. Caregiver’s attitudes (with four response options: completely agree, partly agree, not sure, and completely disagree)
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a. Preventability of preschooler unintentional injury
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b. Self-efficacy to keep child safe from unintentional injury
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c. Necessity of preventing unintentional injury
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2. Caregiver’s supervising behavior (with five response options: always, often, seldom, never, and not applicable)
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2.1 Risky behaviors
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a. Letting child cross the road alone
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b. Taking child to cross a road at a location without a pedestrian crossing
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c. Letting child swim in a pond or river without adult supervision
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d. Looking left and right before taking child to cross the road
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e. Letting child ride a bicycle or scooter on the road
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f. Holding the child or letting the child sit alone on the front passenger seat when riding in a car
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g. Leaving child playing alone on the bed or stairs
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h. Leaving the child alone for a short time when bathing
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i. Adding hot water when the child is still in the bathtub
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j. Feeding child while the child is playing, laughing, or crying
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k. Giving child a large piece of food, or a whole round food (e.g., grape, nut)
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l. Leaving child at home alone
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m. Leaving the child unattended while the adult is cooking or doing housework
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2.2 Safe behaviors
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a. Using child restraints for child when taking a car
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b. Requiring child to wear safety protective equipment when riding a bicycle or scooter
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c. Testing water temperature before bathing the child
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d. Pouring the water out of the bathtub immediately after using it
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e. Keeping hot substances and lighters out of child’s reach
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f. Keeping sharp objects out of child’s reach
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g. Keeping medicines, detergents, sanitizers, antiseptics, and pesticides out of child’s reach
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h. Keeping small objects out of child’s reach
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3. Home environment safety (with six response options: completely like this, mostly like this, partly like this, mostly unlike this, completely unlike this, and not applicable)
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3.1 Risky home environment items
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a. Tablecloths or cloth coverings on tables and cabinets can be pulled
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b. Power cords for electric appliances are not fixed
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c. There are tables, chairs stools, or cabinets beside balconies or windows
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d. There are water spills or oil stains on the floor
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e. There are toys or dolls in the child’s bed
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f. Kitchen supplies like pots, bowls, plates, and cups are placed in child’s reach
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g. Plastic bags or cling wraps are placed in child’s reach
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h. Large round foods like grapes or nuts are placed in child’s reach
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i. Chemicals are stored in non-original containers
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3.2 Safe home environment items
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a. There are protectors on sharp corners
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b. Switches of water dispensers and gas stoves are equipped with protective devices
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c. Balconies and windows are equipped with guard railings
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d. Child’s bed is equipped with guard railings
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e. There are soft protective materials on the floor beside the child’s bed
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f. Water storage supplies are lidded
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g. There are anti-skid devices in the washing and bathing places
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Pilot testing
Prior to the formal study, we will recruit 60 caregivers of preschoolers to participate in feasibility testing (30 from Yang County and 30 from Shicheng County). During a one-week pilot testing phase, participants will complete two online questionnaires. One will collect complete data listed in Table 1 as well as socio-demographic factors, and the other will assess the user’s experience concerning the contents, readability, functions, interface, operability, and usability of the app. The results of feasibility testing will be used to finalize the survey questionnaire and make final refinements to the app.
Collection of formal data
Survey data will be collected at baseline and every 3 months during the entire 18-month follow-up period. All data will be collected online through the app and stored in a password-protected backend database. If caregivers fail to complete an app-based online survey, designated members of the coordinating group will remind or guide them. When needed, a phone-based survey interview will be employed.
Participant engagement data will be gathered and stored in the backend database automatically through embedded tracking of app usage. Data to be collected include: (1) the frequency of logins, (2) time span from login to logout each time, (3) frequency of reading instructional materials, (4) time spent on learning instructional materials, (5) number of reading or bookmarking knowledge disseminations, (6) number of posting comments on knowledge disseminations, (7) number of likes clicked on knowledge disseminations, (8) frequency of joining a discussion in the online forum, (9) number of bookmarked online forum themes, (10) number of comments posted in the online forum, and (11) number of likes clicked in the online forum.
Data analysis plan
Primary data analysis will follow an intention-to-treat (ITT) approach. Descriptive statistics will be calculated for socio-demographic variables and primary and secondary outcomes, including mean (or median) and standard deviation (or range and interquartile range) for continuous variables, and frequency and proportion for categorical variables. For each time point, Chi-square and two-sample t-tests (or Wilcoxon rank sum test if data are skewed) will be used to examine the differences in outcome measures between intervention and control groups for categorical and continuous variables, respectively. Trend tests or ANOVA will used to detect within-group differences across the six follow-up visits.
Generalized Estimation Equations (GEE) will be used to assess the overall effectiveness of the app-based intervention, while adjusting for socio-demographic variables, engagement, and baseline injury events.
A Generalized Linear Mixed Model (GLMM) will be used to verify the GEE results. With GLMM, missing values can be imputed using the Expectation Maximization algorithm (EM). A per-protocol (PP) sensitivity analysis will be conducted to validate ITT results. All statistical analyses will be performed using R version 4.0.4. All statistical tests will be two-sided at the significance level of 0.05.
Subgroup analyses will be conducted to assess the impact of socio-demographic factors on the intervention effect, including gender and age of children and their caregivers, type of children’s caregivers (e.g., parents, grandparents, or others), education level of caregivers, and household income per capita per month. Subgroup analyses will employ the same statistical methods used for the primary analyses.
This study will strictly adhere to the Consolidated Standards of Reporting Trials (CONSORT) 2010 statement [37] and the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) 2013 statement [38] to analyze the data and report the results.