Factors Affecting Capsule Endoscopy Transit Time

Abstract

Backgroud: Efficacy of capsule endoscopy depends on the propulsion of the capsule by gastrointestinal peristalsis. Patient demographics, comorbid conditions and medications affect peristalsis and have an impact on capsule endoscopy transit times and results of the study. Aim: To study the effect of patient factors on capsule endoscopy transit times (CETT). Methods: The study is a retrospective analysis of patients who underwent capsule endoscopy from 2005 to 2006 at a tertiary care hospital in Philadelphia. Data gathered included patient demographics (age, gender, BMI), indications for capsule endoscopy, comorbid conditions (diabetes, hypothyroidism, gastroesophageal reflux disease), medications (calcium channel blockers, senna, proton pump inhibitors) and capsule transit times. Normal esophageal and gastric transit times were defined as less than thirty seconds and three hours respectively. Factors that could delay transit times were evaluated and compared using the Mann-Whitney U test. Results: Fifty four patients had capsule endoscopy performed for various indications (anemia-69%, occult GI bleeding-33%, change in bowel habits-7%). Mean esophageal transit time (ETT) was 8 seconds (n = 38). Sixteen patients were excluded from this calculation based on prolonged ETT. Out of 54 patients, 2 had prolonged gastric transit time (GTT) and the capsule never entered the small bowel. Among patients with normal GTT, mean transit time was 24 minutes. The mean small bowel transit time (SBTT) was 240 minutes. Five capsules did not enter the small bowel and four did not enter the colon. The GTT and SBTT could not be calculated in these patients. Only one patient required surgical removal for retained capsule. Fifty seven percent of the patients were older than 65 years. When compared with patients younger than 65 years, they had a significantly shorter GTT (p = 0.03). Gender, body mass index, diabetes, gastroesophageal reflux disease and use of medications (calcium channel blockers, proton pump inhibitors and senna) had no effect on CETT. Seventeen percent of the patients (n = 9) had hypothyroidism. Patients with hypothyroidism had a statistically significant prolonged small bowel transit time (p = 0.04) when compared to those without hypothyroidism. There was no difference when ETT and GTT were compared in this subgroup. Conclusions: This study demonstrates that CETT is affected by age and hypothyroidism. These factors have to be considered when interpreting CE results. Diabetes and use of calcium channel blockers do not effect capsule endoscopy transit time. Further studies are needed to better define independent risk factors for delayed capsule transit.