The use of specific bowel preparation methods, such as water-exchange colonoscopy, has been associated with increased mucus production in the left colon, requiring supplementary clearing via suction or saline for optimal visualization. Given these procedural demands, further analysis is required to determine if a correlation exists between insertion time and the severity of mucus presentation.

An observational analytical study was conducted in adult patients indicated for colonoscopy. Data of insertion time, endocuff device usage, Boston bowel preparation scale and Left Colon Mucus Scale (LCMS) were collected. LCMS: scored from 0 to 4. A score of 0 indicates absence of visible mucus; 1 indicates clear, visible mucus; 2 denotes opaque mucus in fine strands; 3 denotes opaque mucus in substantial clumps covering one side of the colonic surface; and 4 denotes opaque mucus in extensive clumps obscuring the majority of the lumen. LCMS scores were analyzed in relation to blind insertion time and patient age. Statistical analysis employed Spearman's rank correlation for continuous variables. Odds ratios (ORs) with 95% confidence intervals estimate the risk among stratified groups. A p-value <0.005 defined statistical significance.

A total of 112 colonoscopy procedures, the mean patient age was 59 ± 13 years, and the mean Boston score was 5.53 ± 1.32. A weak-to-moderate but statistically significant positive correlation was identified between insertion time and mucus accumulation (ρ=0.252; p=0.007). Ordinal analysis determined that an insertion duration of 20 to 30 minutes significantly elevated the likelihood of LCMS grade 2 mucus (OR=4.333 [CI=1.434-13.095]; p=0.006), whereas durations exceeding 30 minutes were significantly associated with LCMS grades 3 and 4 (p=0.014). Concerning age, patients aged 18-34 years exhibited a significant association with LCMS grade 2 (OR=6.714; [CI=0.874 - 51.575], p=0.038).

It is noteworthy that younger patients tend to exhibit greater mucus accumulation, suggesting a senescent mechanism in the colonic mucosa where mucus production declines with age. This excess secretion significantly impacts procedural outcomes; inadequate bowel preparation caused by mucus impairs visualization and increases the risk of missing concealed lesions. Therefore, optimizing insertion and procedure times is essential to mitigate the risks associated with this accumulation.