Difficult colonoscopy score identifies the difficult patients undergoing unsedated colonoscopy

BACKGROUND: Many factors have been found to affect the difficulty of colonoscope insertion, such as age, gender, body mass index (BMI), history of abdominal surgery and operator etc. However, a scoring system may be more useful to predict the difficulty during colonoscopy. METHODS: The individual and procedure-related data of 616 patients undergoing colonoscopy were prospectively collected from December 2013 through February 2014 in Xijing Hospital of Digestive Diseases. Cox regression analysis was used to identify high-risk factors associated with difficulty of colonoscopy. A predicting model with the difficult colonoscopy score (DCS) was developed. RESULTS: Total cecum intubation rate was 98.9% (609/616). Advanced age, lower BMI, inexperienced operator and fair or poor sleep quality were identified as independent factors of prolonged insertion time (all p < 0.05), which were used to develop the DCS. Based on the score, patients could be divided into high-risk and low-risk groups with distinct incomplete rates within 10 min (42.0% vs. 16.5%, p < 0.001). Compared with those with DCS ≤ 1, patients with DCS > 1 had increased insertion time (10.6 ± 0.7 min vs. 6.9 ± 0.2 min, p < 0.001) and pain score (1.9 ± 1.5 vs. 1.4 ± 1.4, p = 0.002). More abdominal compression (36.9% vs. 16.8%, p < 0.001) and position change (51.4% vs. 22.6%, p < 0.001) were needed in this group of patients. CONCLUSION: Patients with DCS > 1 had longer insertion time, higher pain score and needed more abdominal compression and position changes. DCS was useful for predicting the difficulty of colonoscope intubation. (ClinicalTrials.gov NCT02105025 05/05/2014). ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12876-015-0273-7) contains supplementary material, which is available to authorized users.