The Use of Capsule Endoscopy For Diagnosis of Iron Deficiency Anemia: A Retrospective Analysis

There was some ambiguity in the recent guidelines on the use of capsule endoscopy (CE) in cases of iron deficiency anemia (IDA).

We aimed to examine the yield of CE in diagnosing the cause of IDA and to define clinical parameters that predict higher diagnostic yields.

A total of 1351 individuals underwent CE in Winnipeg between 2005 and 2016. All studies were reported by 1 reading physician. Data included demographics and requested information on medication use, prior imaging studies, and hemoglobin and ferritin levels. In a total of 620 (46%) patients, CE was indicated for occult gastrointestinal bleeding or IDA. Positive findings on CE were separated into "definite" and "possible." Multinomial regression analysis was used to determine the variables correlated with definite CE findings. A survey analysis was then used to assess how the study results impacted further management.

With regard to the 620 patients, the mean age was 62.9 years, mean hemoglobin level was 89 g/L, and median ferritin level was 9 μg/L. A total of 210 (33.9%) patients had positive findings (definite: 23%, possible: 10.8%). Vascular ectasias were the majority of definite findings (47.5%). Predictors of definite findings were age (relative risk ratio: 1.04; 95% confidence interval: 1.02-1.06) and male sex (relative risk ratio: 1.88; 95% confidence interval: 1.25-2.83). An overall 12.7% of positive studies required therapeutic intervention, with 65.8% undergoing further workup.

We report a 33.9% positive yield, with 65.8% of patients undergoing further workup as a result of CE and 12.7% requiring therapeutic intervention. We conclude that CE plays an important role in the investigation of IDA and occult gastrointestinal bleeding and has important implications on further management.