As the “gold standard” for the diagnosis of intestinal diseases such as colorectal cancer (CRC), colonoscopy provides direct and accurate visualization of the colonic mucosal surface, enabling early detection, accurate diagnosis, and timely intervention, thereby improving patient outcomes [1-3]. In 2021, the US Preventive Services Task Force recommended that people with risk factors such as a family history of CRC, obesity, inflammatory bowel disease, and smoking should undergo regular colonoscopies [4,5]. Even those without these risk factors should undergo CRC screening starting at the age of 45 years and have a colonoscopy every 10 years [4]. The effectiveness of colonoscopy largely depends on the quality of bowel preparation, with adequate cleanliness being essential for a safe, efficient examination and playing a critical role in clinical outcomes [6-8]. However, studies have reported that 20%‐40% of patients undergoing colonoscopy exhibit inadequate bowel preparation, which falls far below the European Society of Gastrointestinal Endoscopy–recommended adequacy standard of 90% [9-11]. Suboptimal bowel preparation may increase the risk of missed lesions, postprocedural complications, and prolonged procedural duration, and necessitate repeat examinations, leading to additional patient discomfort and financial burden [12,13]. Thus, accurate identification of factors associated with bowel preparation holds significant clinical value for improving preparation quality. Numerous studies have identified multiple influencing factors that influence the quality of bowel preparation, including age, gender, BMI, anxiety level, and patient compliance with preparation protocols [14-20]. Strict compliance with bowel preparation instructions is recognized as a critical determinant of successful preparation. Poor compliance with prescribed requirements, including dietary restrictions, fluid intake limitations, and proper medication timing and dosage, may directly affect cleansing efficacy [19,20]. Current research predominantly evaluated compliance through single-dimensional metrics such as laxative consumption or dietary compliance, failing to holistically evaluate the full-process compliance, which includes dietary management, fluid intake restrictions, medication dosage, timing, and duration of medication use [21,22]. This study aims to evaluate the holistic compliance with bowel preparation instructions among patients undergoing colonoscopy and its multidimensional influencing factors in China. The findings will inform the optimization of personalized patient education strategies and the development of targeted preparation guidance, ultimately enhancing compliance to improve bowel preparation quality and subsequent colonoscopy outcomes.

One of our study objectives is to evaluate the compliance rate with bowel preparation of Chinese patients undergoing colonoscopy. The survey results revealed that inadequate bowel preparation compliance among colonoscopy patients was up to 58.0% (429/740), which was significantly higher than the 23.6% previously reported in a study [24]. This may be related to the more multidimensional (including dietary management, fluid intake restrictions, medication dosage, timing, and duration of medication use) and demanding (a score greater than 95% of the total compliance score) assessment of bowel preparation compliance in our study.

Our results showed that patients’ compliance with bowel preparation instructions was related to age, educational level, and knowledge of bowel preparation. Patients in the 65‐74 years age group had higher compliance than younger patients in the 18‐35 years age group. This may be related to the fact that the retired population has more time to read bowel preparation instructions, whereas the younger patients may ignore relevant details due to work pressure and busy routines. Moreover, the busy lifestyle and tendency of young people to eat out may also hinder their strict compliance with the long and complex food list for dietary restriction before colonoscopy [25]. Patients with a higher level of education and better knowledge of bowel preparation are more likely to understand the educational content provided by health care professionals [26,27]. These patients may tend to recognize the importance and benefits of adequate bowel preparation for colonoscopy, thus improving their compliance [24]. In the future, personalized health education content can be developed for patients on the basis of their age and educational level to increase their knowledge and improve compliance. For example, customized instructions with concise content can be designed specifically for young people to address their unique challenges.

In this study, the type of laxative significantly influenced compliance in univariate analysis. However, in multivariate analysis, it no longer emerged as an independent factor, suggesting that the effect of laxative type may primarily influence compliance indirectly through associated experiential factors such as taste satisfaction and physical discomfort. Sodium phosphate and polyethylene glycol are two commonly used clinical laxatives that commonly cause adverse reactions such as bloating, nausea, vomiting, and dizziness [28]. These adverse reactions, as well as poor taste and flavor, may result in patients not being able to take adequate amounts of laxative, leading to poor compliance. Of the 740 patients in this study, more than half (n=391, 52.8%) were unsatisfied with the taste of the laxative used, and close to 60% (n=439) experienced physical discomfort during bowel preparation. A study by Hautefeuille et al [29] also showed that patients described nausea and vomiting as the main reasons for noncompliance with bowel preparation protocols. Therefore, for patients with prior experience of bowel preparation, it is important to inquire about their previous experiences with laxatives when they need to undergo bowel preparation again, and laxatives that are acceptable to the patient in terms of taste should be selected to minimize the occurrence of adverse reactions and improve patient compliance.

There are several limitations of this study. First, this study adopted a convenience sampling method and was conducted in a single tertiary hospital in an urban area, which may have introduced selection bias and led to an overestimation of certain indicators (eg, educational level and health awareness of patients). Future research could expand the study to multiple centers to gain a more comprehensive understanding of patient compliance in different settings. Second, bowel preparation compliance was self-reported, which may introduce recall bias, potentially leading to overestimation or underestimation of actual compliance. In addition, it was assessed using a newly developed scale that has only undergone preliminary validation, and its reliability and generalizability require further confirmation in larger and more diverse populations. Third, this study did not collect results on the quality of patients’ bowel preparation, nor did it explore the correlation between compliance and bowel preparation quality. Lastly, due to the cross-sectional design, it is not possible to establish causal relationships. Overall, these limitations highlight critical areas for future research and improvement in understanding and bowel preparation compliance in patients undergoing colonoscopy.

This study revealed that patients had relatively low compliance with bowel preparation. Independent factors identified included age, educational level, knowledge of bowel preparation, satisfaction with the taste of the laxative, and physical discomfort during bowel preparation. Based on the data from this study, we recommend personalizing the educational content of bowel preparation according to the patients’ age and literacy level, and selecting the type of laxative that the patient is satisfied with when available. Our study provides insights for improving bowel preparation compliance in patients undergoing colonoscopy.