Diagnostic yield and predictive factors of findings in small-bowel capsule endoscopy in the setting of iron-deficiency anemia.

Introduction:  Despite the widespread use of small-bowel capsule endoscopy (CE), there is still limited data on its utility and effectiveness for the diagnosis and management of patients with iron-deficiency anemia (IDA).

Aim:  To assess the diagnostic yield of CE and the factors predicting positive findings in patients with IDA.

Methods:  Patients with unexplained IDA and negative upper and lower endoscopy were included. A positive diagnostic yield was considered when CE diagnosed one or more lesions that could explain the IDA. Sex, age, NSAID consumption, blood transfusion requirement, and ferritin and hemoglobin levels were recorded.

Results:  In total, 120 CE were included (mean age 58.5 years; F/M 82:38). Mean hemoglobin levels were 9 g/dL and mean ferritin levels were 15.7 ng/mL. Positive findings were present in 50 % of patients. The most frequent was angiodysplasia (45 %). Despite several baseline variables being significantly associated with positive findings, using a logistic regression model, it was verified that male sex (OR 3.93; 95 %CI 1.57 - 9.86), age (OR 1.03; 95 %CI 1.00 - 1.06), and hemoglobin levels (OR 0.73; 95 %CI 0.57 - 0.94) were the variables having an independent effect on the probability of obtaining positive findings. Age older than 50 years (OR 14.05; 95 %CI 1.69 - 116.23) and male sex (OR 3.63; 95 %CI 1.29 - 10.17) were the variables which increased the risk of diagnosing angiodysplasia.

Conclusions:  CE is a useful technique in patients with IDA. To improve its yield, it is necessary to select patients carefully. Male sex, older age, and low hemoglobin levels were associated with a risk of positive finding in this group of patients. The risk of diagnosing angiodysplasia increased with male sex and older age.