The Effect of Obesity on the Quality of Bowel Preparation for Colonoscopy Results From a Large Observational Study Ava B. Anklesaria, MBBS,*† Elena A. Ivanina, DO,† Kenechukwu O. Chudy-Onwugaje, MBBS, MPH,† Kevin Tin, MD, MBA,† Chaya M. Levine, MD,† Peter Homel, PhD,†✠ Mary Rojas, PhD,† Ira E. Mayer, MD, FACG,† and Rabin Rahmani, MD, FACG† Background: Obesity has been linked to suboptimal bowel prepa- ration but this association has not been conclusively investigated in prospective studies. Goals: Our objective was to determine whether any relationship exists between obesity as measured by body mass index (BMI) and quality of bowel preparation. Study: Adult patients who presented for outpatient colonoscopy at a single urban ambulatory surgery center within a 6-month period and fulfilled inclusion criteria were prospectively enrolled for the study. Patients were divided by BMI into subcategories based on the World Health Organization international classification of obesity. The Modified Aronchick scale was used to assess bowel preparation for colonoscopy. A univariate and multivariate analysis was used to determine a possible association between BMI and poor preparation. Results: A total of 1429 patients were evaluated. On the basis of inclusion criteria, 1314 subjects were analyzed, out of which 73% were overweight or obese. Inadequate bowel preparation was noted in 21.1% of patients. There was no correlation between obesity and the quality of the bowel preparation. Male gender (P = 0.002), diabetes mellitus (P < 0.0001), liver cirrhosis (P = 0.001), coronary artery disease (P = 0.003), refractory constipation (P < 0.0001), and current smoking (P = 0.01) were found to be independently pre- dictive of poor bowel preparation. Conclusions: Increased BMI is not predictive of suboptimal bowel preparation for colonoscopy. The results of our study are pivotal given the increased risk of colorectal cancer in obese patients and their known lower rate of colorectal cancer screening in certain populations. It is important to avoid subjecting these patients to an intensive bowel preparation that may further discourage screening in a patient population that requires it. Key Words: obesity, bowel preparation for colonoscopy, colorectal neoplasia, colon cancer screening (J Clin Gastroenterol 2018;00:000–000) T he global rise in obesity is arguably the single most important public health challenge of our time. Its grave impact on overall morbidity and mortality rates arises from an increased risk of cardiovascular disease, stroke, diabetes mellitus, and certain cancers, all of which are leading causes of death in the United States. 1,2 Recent data suggest that an estimated 2.1 billion people, ∼30% of the world’s population are either overweight or obese. 3 The prevalence of obesity is currently at epidemic levels in the United States with the average age adjusted prevalence of obesity among men being 35% and 40.4% in women. 4 It has been estimated that by 2030, 86% of US adults will be overweight or obese. 5 In addition to its deleterious effect on physical health, obesity places an enormous financial strain on health care systems. The direct and indirect cost of obesity and related conditions accounts for ∼20.6% of US national health expenditures; with an estimated annual national medical care cost of $315.8 billion (year 2010 values). 6 A major portion of this expenditure is due to the increased cost of treatments or procedures for obese individuals. Colonoscopy is one of the most commonly performed outpatient procedures in the United States with an estimated 15 million colonoscopies performed in 2012. 7 An inadequate bowel preparation for colonoscopy results in missed lesions, prolonged procedure time, the need for repeat procedures, and an increased risk of adverse events, all of which con- tribute to higher health care costs. A study by Rex et al 8 estimated that imperfect bowel preparations increase colo- noscopy cost by 12% to 22%. The relationship between obesity and increased risk of colorectal neoplasm is well studied. There is a positive association between increased body fat and an increased risk of colorectal cancer (CRC), adenomas, and adenoma recurrence after polypectomy. 9–12 The consequences of an inadequate preparation are there- fore worse in obese patients given their increased risk of colorectal neoplasm and the higher risk of sedation-related adverse events in this patient cohort. 13,14 Thus, it is clinically important to ascertain if obesity is an independent risk factor for poor bowel preparation for colonoscopy. A handful of studies have investigated obesity and its relationship to inadequate bowel preparation for colono- scopy with conflicting results. 15–19 Two retrospective studies 1 published by Borg et al 15 and another using split dose preparation by Fayad et al 17 specifically evaluated bowel preparation and obesity and concluded that obesity was an independent predictor of poor bowel preparation. Another prospective study by Hassan et al 16 also demonstrated an association between being overweight and inadequate preparation for colonoscopy, however, the study did not Received for publication July 20, 2017; accepted March 15, 2018. From the *James J Peters VA Medical Center, Mt Sinai School of Medicine, Bronx; and †Maimonides Medical Center, Albert Ein- stein School of Medicine, Brooklyn, NY. ✠ Peter Homel deceased. Present address: Ava B. Anklesaria, MBBS, Kings County Hospital Center, SUNY downstate Medical Center, Brooklyn, NY. Present address: Elena A. Ivanina, DO, Lenox Hill Hospital, NY, NY. Present address: Kenechukwu O. Chudy-Onwugaje, MBBS, MPH, University of Maryland Medical Center, Baltimore, MD. The authors declare that they have nothing to disclose. Address correspondence to: Ava B. Anklesaria, MBBS, 375 South End Ave., Apt 28 T, New York, NY 10280 (e-mail: avaanklesaria@gmail.com). Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved. DOI: 10.1097/MCG.0000000000001045 ORIGINAL ARTICLE J Clin Gastroenterol  Volume 00, Number 00, ’’ 2018 www.jcge.com | 1 Copyright r 2018 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited. This paper can be cited using the date of access and the unique DOI number which can be found in the footnotes.