Letter to the Editor: Comparative Efficacy and Safety of 0.8‐L Versus 2‐LPolyethylene Glycol‐Ascorbic Acid Solutions in ColonoscopyPreparation: A Prospective, Multicenter, Randomized, and Controlled Trial

We read with great interest the prospective randomized controlled trial by Lee et al. 1, which established the noninferiority of a novel 0.8-L polyethylene glycol–ascorbic acid (PEG-Asc) solution compared to the standard 2-L PEG-Asc regimen for colonoscopy preparation. This methodologically rigorous trial provides compelling evidence supporting the low-volume formulation as a valuable advancement in bowel cleansing protocols. While we commend the authors for their well-designed study, we wish to offer constructive observations to help contextualize the findings and suggest directions for future research. First, regarding the generalizability of the results, the exclusion of patients with body mass index ≥ 30 kg/m2 may constrain direct applicability to real-world settings, particularly given the high prevalence of obesity in screening populations 2. Similarly, limited representation of older adults is concerning as this demographic bears the highest colorectal cancer burden 3. Subsequent research intentionally including these prevalent patient subgroups would better elucidate the preparation's broad utility. Second, we identify a methodological consideration in the hydration protocol. The administration of different water volumes across groups (0.5 L with 2-L PEG in Group C vs. 0.8 L with 0.8-L PEG in Groups A and B) introduces a potential confounding variable. This deviation from standardized protocols emphasized by the European Society of Gastrointestinal Endoscopy Guideline 4 undermines internal validity by making it difficult to attribute outcomes solely to the PEG formulations being compared. Implementing a uniform water volume would have strengthened the study design. Third, we wish to highlight two important aspects of preparation quality that warrant further investigation. The significantly superior cleansing efficacy in the ascending colon among patients receiving the same-day regimen (Harefield Cleansing Scale scores 3.2 vs. 3.0, p = 0.01) suggests potential advantages for detecting right-sided lesions. This is particularly relevant given the established association between missed right-colon diagnoses and interval cancer risk 5. Additionally, while the incorporation of simethicone provided a clear advantage in reducing intraluminal bubbles and likely improved mucosal visibility, its ultimate effect on lesion detection rates requires systematic evaluation beyond bubble score assessments. Finally, although patient-reported outcomes were appropriately evaluated, incorporating objective metrics of tolerability and safety, such as electrolyte balance and renal function parameters, would strengthen future assessments, particularly in vulnerable patient populations where safety concerns are paramount 6. In summary, we commend Lee et al. for their rigorous demonstration of noninferiority. To maximize the clinical impact of these findings, we recommend: (1) expanding enrollment to include underrepresented populations to enhance generalizability; (2) adopting uniform hydration protocols consistent with ESGE guidelines; (3) conducting segment-specific analyses of right-colon lesion detection given its clinical importance; and (4) incorporating objective safety metrics particularly for vulnerable populations. These refinements will further validate the promising role of low-volume preparations in improving colonoscopy quality and patient experience. This work was supported by the Youth Talent Cultivation Program of the China Association of Chinese Medicine (202557-011). This letter does not require ethical approval. All authors approve the submission. The authors declare no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.