Enhanced diagnostic yield with prolonged small bowel transit time during capsule endoscopy

Background: The effect of small bowel transit time (SBTT) on diagnostic yield during capsule endoscopy (CE) has not been previously evaluated. Our study aim was to assess the effect of SBTT on the likelihood of detecting intestinal pathology during CE. Methods: We reviewed collected data on CE studies performed at Johns Hopkins Hospital from January 2006 to June 2007. In patients investigated for anemia or obscure bleeding, the following lesions were considered relevant: ulcers, erosions, AVMs, red spots, varices, vascular ectasias, and presence of blood. In patients with diarrhea or abdominal pain, ulcers, erosions, and blood were considered relevant. Age, gender, study indication, hospital status, and quality of bowel preparation were identified as candidate risk factors affecting SBTT. Univariate logistic and linear regression analyses were performed to study the effect of SBTT on diagnostic yield. Results: Total of 212 CE studies were analyzed; most were in outpatients (n=175, 82.9%) and with excellent bowel preparation (n=177, 83.5%). Mean SBTT was 237.0min (3.9hrs). Age, gender, bowel prep, hospital status, and study indication did not significantly affect SBTT. However, increased SBTT was independently associated with increased diagnostic yield; OR=1.7 in SBTT=2-4hr (p=0.41), OR=1.8 in SBTT=4-6hrs (p=0.30), OR=9.6 in SBTT=6-8hrs (p=0.05). Conclusion: Prolonged SBTT during CE (>6 hr) is associated with an increased diagnostic yield. This may be due to a positive effect on image quality during a "slower" study. The use of promotility agents may adversely affect the ability of CE to detect significant intestinal pathology.