To identify which symptoms are significantly associated with patients who are able to complete the PEG full-dose high-volume bowel preparation. Unlike previous studies, which have largely focused on tolerance or completion rates using dichotomous symptom reporting, this study aimed to evaluate symptom intensity using a Likert scale to better characterize the severity of patients’ most frequent complaints.

A multicenter, cross-sectional study was conducted in adult patients indicated for colonoscopy. Sociodemographic data, comorbidities, medication use, history of prior colonoscopy, and specifics of colonoscopy preparation were collected via face-to-face questionnaires. Symptomatology during preparation was assessed, and the Hospital Anxiety and Depression (HAD) Scale was administered. Symptom intensity was evaluated on a 0-5 Likert scale, with scores of 3 or higher deemed significant.

Of 163 patients, 85 were female (61.7%). The average age was 50 ± 14 years. Patients with significant symptoms: Nausea (26/44) was associated with females (OR=6.591, CI=2.057-21.122, p=0.001), and those with less than 50 years (OR=8.834, CI=2.55-30.580, p=0.048). Vomiting (5/11) was associated with NSAID use (OR=7.236, CI=1.022-51.244, p=0.007). Abdominal pain was associated with NSAID use (OR=7.657, CI=1.404-41.757, p=0.019). Increase in bowel movements (67/99) was less frequent in those younger than 50 years (OR=0.429, CI=0.204-0.904, p=0.026). Bloating (33/50) was most commonly associated with females (OR=3.481, CI=1.439-8.423, p=0.006) and those with less than 50 years (OR=4.762, CI=1.595-14.215, p=0.005). Postprandial fullness (47/65) was associated with a history of colon cancer (OR=6.328, CI=1.154-34.690, p=0.034). Flatulence/burping (31/64) was mostly associated with females (OR=4.694, CI=1.794-12.284,p=0.002). Anal itching (39/70) was related with history of anxiety (OR=8.093, CI=1.374-47.673, p=0.021), and abdominal surgery (OR=5.634, CI=1.650-19.239, p=0.006). Chills (19/38) with females (OR=10.997, CI=1.260-96.003, p=0.030). Cramping (2/15) more frequent in those with colorectal cancer history (OR=24.787, CI=1.124-546.476, p=0.042). Weakness (27/50) was mostly associated with females (OR=2.899, CI=1.023-8.213, p=0.045) and less associated with straw use to drink the preparation (OR=0.337, CI=0.128-891, p=0.028). A cold or hot sensation (32/58) was associated with females (OR=4.811, CI=1.735-13.343, p=0.003). Excessive thirst (23/41) was associated with postgraduate degree (OR=6.764, CI=1.419-32.237, p=0.016) and anxiety per HAD (OR=3.274, CI=0.421- 25.460, p=0.022) remained significant.

The severity of symptoms during bowel preparation was strongly associated with specific demographic, clinical, and psychological factors. Notably, being female, younger age, and anxiety or depression were consistently associated with more severe symptoms. In contrast, certain behaviors, such as drinking with a straw, were linked to reduced symptom burden. Recognizing these specific factor-symptom connections can help personalize preparation strategies