This study is an interventional investigation conducted in accordance with research ethics regulations. Approval from the Institutional Review Board of Taipei Veterans General Hospital was obtained prior to the commencement of the study (approval number 2021-10-007AC). The study was conducted from October 27, 2021, to December 31, 2022. Before enrolling participants, the purpose and details of the study were explained to them, and they provided informed consent by signing a consent form. Throughout the research process, all participants’ privacy rights were strictly protected, and the collected data were used solely for research purposes. Participants were not compensated for their participation in this study.

G*Power 3.1.9.7 for Windows was used to analyze the questionnaire data, considering a power (1-β) of 0.8, α value of .05, a medium effect size of 0.3, and an estimated dropout rate of 20%. As a result, a sample size of 40 participants was determined. A total of 40 outpatients from the gastroenterology and endoscopy center of the medical center were recruited. The inclusion criteria were patients aged 20 years or older, recommended by physicians to undergo colonoscopy, without visual or hearing impairments, and without mental illnesses. After explaining the purpose and content of the study and obtaining written informed consent, paper-based nursing instructions were provided along with verbal explanations of ColonClean, and the BP was conducted. For easy access to ColonClean, the participants downloaded the ColonClean mHealth app on their mobile devices after scanning a QR code. The nursing instruction process involved 1-on-1 teaching, with an explanation lasting approximately 20 minutes in the independent waiting area outside the outpatient visit room. Each research participant was asked to submit feedback on their experience with ColonClean within 3 days of their colonoscopy.

Individuals aged ≥50 years are the target group for CRC screening, making them the primary users of the ColonClean mHealth app. Considering the physiological and cognitive decline in older adults, it is crucial to design a user-friendly interface to avoid difficulties in usage. The interface design for older adults incorporates intuitive elements, clear and concise text, and straightforward operational steps [23]. Contrast colors were used for interface color schemes. The operational methods are simple and clear, with functions executed through clicks or straight-line swiping gestures [24,25]. All features were designed to operate within a single page, avoiding menu structures with more than 2 layers of information. This design reduces the psychological pressure on older adults, who may be afraid of making mistakes due to an unfamiliarity with technology; this allows them to focus and read the important information comfortably. Handwritten or voice inputs were preferred for filling in the forms. Clear return or cancel buttons were placed at the top or bottom of the screen. Considering the characteristics of the users, the emphasis was on interaction and feedback rather than simple page browsing to enhance the impression of BP.

The ColonClean mHealth app was developed using the Android 11 operating system due to its low development cost and popularity among the general public [26]. The user interface and content were designed using the Android app package, the Java programming language, and a built-in database.

The screen display of ColonClean is divided into 3 sections: top, middle, and bottom in a single-page layout for the main screen. The top section displays the “Examination Date and Time.” The middle section features 6 key topics arranged in a zigzag pattern based on their importance. From left to right, these topics include “Dietary Guidelines,” explaining the necessary dietary education starting 3 days before the examination as shown in Figure 1, and “Laxative Use,” explaining the use of bowel cleansing medication. The “Fluid Intake” screen is for recording the amount of fluid consumed (Figure 2), while the “Stool Image Recognition” screen is for providing images to identify the type of the last bowel movement (Figure 3).

“Precautions” explains important points to keep in mind. The bottom section of the screen, from left to right, includes the “Home” button to return to the main screen; “Notifications,” which displays text messages; “Medication,” which provides settings and modifications for regular medication or bowel cleansing agents; and “Questionnaire,” which allows users to provide feedback on their experience using the ColonClean mHealth app.

The ColonClean app sent reminders and notifications to participants in the experimental group starting 3 days before their procedure. These notifications advised participants to begin dietary restrictions, such as avoiding high-fiber fruits and vegetables. Two days before the procedure, the app reminded users to switch to a low-residue diet, focusing on foods like congee or plain white noodles. The day before the procedure, the app prompted users to follow a clear liquid diet, including oil-free broth and sports drinks, and provided instructions on taking BP medications.

The app utilizes tap and swipe gestures for navigation; for user registration, it supports built-in Chinese phonetic input or handwriting recognition on mobile devices. The interface features a fresh color palette, primarily a warm lake green. Key information is highlighted in red, and unnecessary content is removed to offer concise summaries. Unique icons are designed as entry pointers to access relevant content. Tapping on an icon triggers entry into the main menu, which includes dietary guidance, instructions on using bowel cleansing agents (via images and videos), precautions for a colonoscopy, and fluid intake records, and provides references to the type of last bowel movement for understanding the differences compared to that during endoscopy. The design allows users to navigate intuitively, freely scrolling, tapping, and browsing related content between pages [27,28]. Push notifications are recommended to include instructions or prompts. Therefore, through push notifications, users are informed about relevant BP information to avoid any execution errors. Considering the user groups are middle-aged and older adults, complex actions are avoided. Instead, the key content is displayed directly in the push notification message. When a notification is received, users can click on the pushed message, which leads them to the relevant page with clear instructions or recommendations to view more detailed content. This approach reduces the chance of users misunderstanding the message. The user-centered push notification feature for BP steps enhances user engagement [29,30].

After completing a colonoscopy, the physician submits a rating of the BP level using the Aronchick Bowel Preparation Scale (ABPS) in the endoscopy report system [1,31,32]. The ABPS is one of the most comprehensive and commonly used scales to describe the visualization of the colon and assess the percentage of stool covering the entire colon mucosa to explain the state of BP [33]. Based on this assessment, the adequacy of bowel cleansing is graded as excellent, good, fair, poor, or inadequate [11,33-35]. In Taiwan, domestic quality indicators for colonoscopy align with ABPS standards, targeting a 90% or above rating for both “excellent” and “good” categories. This ensures a high standard of care in colorectal screening, enhancing procedural accuracy and improving patient outcomes [36,37].

The TAM explains the behavior of users accepting new information technology in the field of computer technology [38]. Perceived usefulness and perceived ease of use affect users’ attitudes toward adopting new technology, thereby influencing willingness and usage behavior. The perceived ease of use, perceived usefulness, attitudes, and behavior of outpatient endoscopy patients toward the ColonClean mHealth app were evaluated to assess their acceptance of using it. The questionnaire adopted a 5-point Likert scale. The 4 dimensions assessed by outpatient endoscopy patients after using ColonClean were perceived ease of use, perceived usefulness, attitudes, and usage behavior. The response options ranged from 1=“strongly disagree,” 2=“disagree,” 3=“neutral,” 4=“agree,” to 5=“strongly agree.” Higher scores indicated a higher level of agreement, while lower scores indicated a lower level of agreement. The questionnaire was initially developed based on literature references [39]. Three nursing informatics experts and scholars were then invited to evaluate the applicability and clarity of each question and to provide suggestions for improvement.

The Cronbach α coefficient was used to assess the internal consistency of the questionnaire items in this study. For the perceived usefulness dimension, consisting of 6 items, Cronbach α was 0.971. For the perceived ease of use dimension, consisting of 6 items, Cronbach α was 0.950. For the attitude dimension, consisting of 5 items, Cronbach α was 0.930. For the usage behavior dimension, consisting of 6 items, Cronbach α was 0.976. The questionnaire comprised a total of 23 items, and the Cronbach α coefficient for the scale was 0.986, indicating high internal consistency, meeting the requirement of a Cronbach α coefficient exceeding 0.7.

The structured questionnaire was designed and validated for reliability and validity by 3 nursing informatics experts. Participants accessed the questionnaire through a built-in link within the app, with the collected data stored in the backend management center for subsequent analysis.

The data were analyzed using SPSS 25.0 (IBM Corp), with the utilization of the Pearson product-moment correlation and simple regression analysis to predict the perception of ColonClean.

The demographic characteristics of the participants were as follows: 17 males (43%) and 23 females (58%); 27 participants aged ≥50 years (68%); and 35 participants with a high school/vocational education or above (88%).

After completing their colonoscopy, each research participant provided feedback on their experience with the ColonClean app within 3 days.. The feedback highlighted several key aspects of the app’s design that contributed to user satisfaction and engagement:

Overall, the research results indicated that users found the design of the ColonClean app effective in enhancing their understanding of and compliance with BP instructions. The app’s focus on intuitive navigation, visual aids, and timely reminders contributed to a positive user experience, ultimately improving the effectiveness of BP for colonoscopy.

After completing the colonoscopy, the BP level is reported by the endoscopist using the ABPS: 10 individuals (25%) achieved a “fair” level, 26 individuals (65%) achieved a “good” level, and 4 individuals (10%) achieved an “excellent” level. There were no cases of “poor” or insufficient preparation leading to interruption or inability to perform the examination.

Mobile health apps are increasingly used for illness prevention, education, and promoting healthy lifestyles [40]. However, the requirements for BP are often complex and challenging for patients to navigate and remember. To help outpatient colonoscopy patients adhere to dietary guidelines, manage bowel cleansing agents, and maintain regular medication schedules, push notifications were incorporated into the app’s design. The app, protected under the patent titled “ColonClean Mobile Management System” (patent number M639094, Republic of China), features a user-centric interface that is both intuitive and visually appealing. The well-designed interface, content, push notifications, and multimedia section of the ColonClean mHealth app provide users with a convenient and helpful experience when using their mobile devices for health management. Users expressed their willingness to use the app again in the future and recommend it to family and friends, highlighting its effectiveness as an educational guide for BP.

Despite the overall positive reception of the ColonClean app, some users indicated a preference for paper-based instructions, as reflected in the lower mean score (mean 4.350.77) on this aspect. This finding aligns with existing literature suggesting that certain users may find physical formats more reliable or easier to reference than digital alternatives [41]. Factors contributing to this preference may include concerns about technology accessibility, device compatibility, or personal comfort with digital apps for health management.

Additionally, the preference for paper-based instructions may arise from a desire for tangible resources that can be easily annotated or highlighted [42]. Some users may feel that printed materials provide a more straightforward and immediate reference during the preparation process, particularly in situations where mobile devices are not accessible or convenient [43]. Therefore, while the digital format of the ColonClean app offers numerous advantages, such as interactivity and real-time updates, it is essential to recognize the value that traditional paper-based resources continue to hold for certain individuals.

The ColonClean app operates on the Android system and functions as an mHealth app for mobile devices. However, it is important to note that during the acceptance process, instances may arise where individuals with non-Android operating systems or outdated device models are unable to be included in this study. Those unable to download ColonClean by scanning the QR code were excluded. It is advisable to consider optimizing future mHealth apps so that they can be integrated into mobile devices of various operating systems. This enhancement would contribute to more inclusive nursing guidance for BP, ensuring accessibility across platforms.

In the current era of smart health care, it is recommended to incorporate artificial intelligence recognition capabilities into the ColonClean app. Specifically, for the section where users capture images of their last bowel movement, artificial intelligence can automatically analyze and determine the quality of the stool, categorizing it as “excellent,” “good,” “fair,” or “poor.” This improvement would facilitate a more accurate assessment of the final bowel movement status. Furthermore, optimizing the ColonClean mHealth app for other individuals who require BP, such as those undergoing colorectal surgery or hospitalized patients preparing for colonoscopy, would ensure the successful completion of bowel cleansing.

Additionally, in light of the COVID-19 pandemic, when individuals undergoing screening needed to reschedule their appointments due to a positive diagnosis or being a close contact, or when they encountered issues like poor bowel movements, a consultation chat window was recommended as a future addition to address user inquiries and provide real-time solutions, thus maintaining user engagement and satisfaction. To ensure the continuity of examinations and achieve the objectives of examination, diagnosis, and treatment, it is crucial to minimize ineffective examinations or schedule cancellations that may impact individuals in need of these examinations. This approach aims to maintain a steady number of examinations and fulfill the purpose of providing necessary medical assessments and subsequent care.

In summary, while the ColonClean app shows promise in supporting BP, it is essential to recognize user attitudes toward traditional paper-based instructions. Enhancing the app with broader accessibility, artificial intelligence capabilities, and additional user support features could significantly improve its effectiveness and reach, ultimately contributing to better health outcomes for patients requiring BP.