The Diagnostic Yield of Capsule Endoscopy in Patients with Iron Deficiency Anemia and a Negative Endoscopic Workup

Abstract

Background: Capsule endoscopy (CE) is now a well established method for investigating the small bowel (SB). However, its yield in detecting significant findings in patients with iron deficiency anemia (IDA) who have undergone a negative endoscopic workup is not well investigated. Methods: Between May 2002 and July 2008 a total of 240 CE procedures for IDA were performed. Clinical information, documentation of IDA and prior negative endoscopic workup were collected prospectively at our institution. The PillCam SB video capsule (Givenimaging Ltd.) was used. Capsule images were interpreted by two experienced gastroenterologists (2). A bivariant analysis was used to determine whether CE findings were associated with each of the demographic and clinical variables for patients with anemia (n=240). Results: The majority of the 240 patients (67%) had normal findings and no source for IDA could be identified. The total number of IDA patients with findings that could explain SB bleeding was 80 (33%), some patients had more than one finding. Findings that were felt not likely to be a source IDA were found in 23 patients (9.6%). The number of units transfused had no correlation with a positive or negative finding (p=0.923). Use of NSAIDs came close to being statistically significant for positive findings (p=0.073). Prior findings on endoscopy had no influence on CE findings (p=0.104 and p=0.070). Age and gender were also not predictive. Using a multivariant analysis, the only significant predictive factor for findings in CE were transfusion requirements, the odds ratio was 3.3 (p<0.001) and 95% CI 1.72 to 6.37. Conclusions: Findings that could explain blood loss from the SB were found in 33% of 240 IDA patients. An active site of SB bleeding was found in 5% of patients. Only one (0.42%) small bowel tumor was identified. The best positive predictor for findings on CE is a history of a prior blood transfusion. The majority of patients with IDA (67%) referred for CE did not have a finding that could account for SB bleeding.