Efficacy and tolerability of colonoscopies in overweight and obese patients: Results from a national database on gastrointestinal endoscopic outcomes

Abstract

Background and study aims Gastroenterologists are encountering a rising number of obese patients requiring colonoscopy. Existing literature regarding colonoscopy outcomes in this population is scant and conflicting. We analyzed a nationwide cohort of patients to identify the effects of body mass index (BMI) on colonoscopy success, efficacy, and tolerability. Patients and methods The Clinical Outcomes Research Initiative (CORI) endoscopic database was queried for all colonoscopies in adults between 2008-2014. Patients were stratified into four cohorts based on BMI classification for comparison. Multivariable analysis was performed to identify the effect of BMI on procedure outcome, efficacy and tolerability. Results Of 41,401 procedures, 27,696 met study inclusion criteria. Of these, 49.4 % were performed for colorectal cancer screening, most commonly under anesthesia directed sedation. Patient discomfort was the reason for an incomplete colonoscopy in 18.7 % of all cases, and more frequent among the overweight and obese cohorts. An inadequate bowel preparation was most common in the class III obesity cohort. Compared to the normal BMI group, a BMI ≥ 30 and < 40 kg/m ² was associated with an increased odds of an incomplete colonoscopy ( P = 0.001for overweight, P = 0.0004 for class I/II obesity), longer procedure ( P < 0.05 for all) and poorer tolerance ( P < 0.0001 for class I/II obesity, P = 0.016 for class III obesity). Anesthesia-administered sedation was more commonly used than endoscopist directed sedation amongst the obese cohort compared with the normal BMI cohort ( P < 0.0001). Conclusions Endoscopists should consider the increased odds of incomplete colonoscopy, longer procedures, and poorer tolerance when performing colonoscopy in obese patients to improve clinical management and procedural outcome.

Fig. 1

Study flow diagram. Allocation of patients into four cohorts based on the classification of weight status by BMI: “Normal Weight” (BMI: 18.5 to ≤ 24.9 kg/m ² , n = 8,020); “Overweight” (BMI: ≥ 25.0 to ≤ 29.9 kg/m ² , N = 10,274); “Class I/II Obesity” (BMI ≥ 30.0 to ≤ 39.9 kg/m ² , N = 7,975) and; “Class III Obesity” (BMI > 40.0 kg/m ² , N = 1,286). Excluded colonoscopies with significant data missing (i. e. extent of colon reached, provider administering sedation, patient’s height and weight for calculation of BMI), procedures performed in patients < 18 years old and procedures performed in patients with a BMI < 18.5 and > 60 kg/m ² .

Fig. 2

Adjusted odds ratios comparing overweight BMI, Class I/II obesity and Class III obesity subgroups to normal BMI subgroup. Odds ratios are based on adjusted analysis comparing the effects of BMI (overweight and obese BMI versus normal BMI subgroup) on certain procedure and sedation related variables during colonoscopy exams. Adjusted odds ratios are presented for all colonoscopies among the overweight BMI and obese class I/II and class III BMI subgroups as compared to the normal BMI subgroup. ^† As reported by the endoscopist. ^¥ Other personnel: endoscopists, non-gastrointestinal physicians, advance practice providers. * All values portrayed are adjusted for each of the variables included in this model.

Fig. 3

Rate of incomplete colonoscopies due to patient discomfort and inadequate bowel preparation by BMI subgroup. Among the entire study cohort, 18.7 % (n = 119) of colonoscopies were incomplete or aborted due to “patient discomfort” (as reported by the endoscopist) and 38.8 % (n = 246) of colonoscopies were incomplete or aborted due to a poor or inadequate bowel preparation (as defined by a BPPS score of 0–3). A higher rate of colonoscopies incomplete due to an inadequate bowel preparation is observed in the normal BMI subgroup (41.5 %) whereas a higher rate of colonoscopies incomplete due to patient discomfort is observed in the Class III obesity subgroup (27.4 %).

Fig. 4

Colonoscopy Exam Duration by BMI subgroup. Colonoscopy procedure duration (minutes) are categorized into 15-minute intervals (< 15 min, > 15 to < 30 min, > 30 to < 45 min, > 45 to < 60 min and > 60 min) for the purposes of analysis. Percentage of colonoscopies that fall within each duration category, by BMI subgroup, is portrayed. While the majority of procedures were less than 15 minutes among the entire cohort (74.8 %), a higher proportion of patients in the Class I/II and III obesity subgroups had procedures lasting > 30 minutes as compared to normal and overweight BMI subgroups.