Does Size Really Matter? A Prospective Study to Evaluate Body Habitus and Difficulty Level of Colonoscopy

Abstract

Background: Colonoscopies are more difficult in those with lower body mass indexes (BMI) based on a few studies that address this issue; many are retrospective or small and none include morbidly obese patients. Consequently, discordance exists as to whether BMI can effectively predict difficult colonoscopies. The aim of this study is to determine how BMI impacts cecal intubation time, and particularly to determine if morbid obesity is directly or inversely related to cecal intubation time. Methods: This is a prospective study of 1448 consecutive outpatient colonoscopies. Exclusion criteria included colonic resection and strictures or exophytic masses precluding colonic evaluation; all other patients were included. Various demographic, anatomical, and historical data were recorded. BMI and mean cecal intubation time and rate were calculated. Results: Of the 1448 patients, 59% were female, 77% were African-American, 11% had a normal BMI, 44% were overweight, 36% were obese, and 9% were morbidly obese. Mean cecal intubation time (in seconds) for females and males were 679.3 ± 414.7 and 604.1 ± 427.5, respectively. Mean cecal intubation time for BMI categories are as follows: normal was 719.26 ± 464.95, overweight was 651.44 ± 416.93, obese was 627.46 ± 410.93, and morbidly obese was 628.78 ± 423.03. The association between cecal intubation time and BMI was assessed using ANOVA adjusted for age, gender, experience level, and sedation. The log transformation of cecal intubation time was used in all analyses in order to satisfy normality assumptions. Mean log cecal intubation time (in seconds) with standard error (SE) for normal BMI was 6.39 (0.045), overweight was 6.28 (0.025), obese was 6.23 (0.028), and morbidly obese was 6.16 (0.054) [p = 0.0025]. The p-value for pair-wise comparisons of normal/overweight was 0.022, normal/obese was 0.0016, normal/morbidly obese was 0.0007, and overweight/morbidly obese was 0.037. Conclusions: Increasing BMI leads to shorter cecal intubation times across all BMI categories; this holds true for the morbidly obese, as well.