Original articleClinical endoscopyDiagnostic yield of small-bowel capsule endoscopy in patients with iron-deficiency anemia: a systematic review

BackgroundIron-deficiency anemia (IDA) is the most common cause of anemia worldwide. Current guidelines recommend the use of small-bowel capsule endoscopy (SBCE) in IDA. Evidence of the validity of SBCE in patients with IDA alone is still limited.ObjectiveTo assess the diagnostic yield (DY) of SBCE in IDA by pooling data from relevant studies.DesignSystematic review and meta-analysis. Fixed-effects or random-effects models were used as appropriate.SettingStudies that estimated the DY of SCBE in IDA were identified. Two investigators independently conducted the search and data extraction.PatientsA total of 24 studies enrolling 1960 patients with IDA who underwent SBCE were included.Main Outcome MeasurementsPer-patient DY, with 95% confidence intervals. Subgroup analysis was also performed.ResultsThe pooled DY of SBCE in IDA, evaluated by a random-effects model, was 47% (95% CI, 42%-52%), but there was statistically significant heterogeneity among the included studies (inconsistency index [I2] = 78.8%, P < .0001). The pooled DY of SBCE in studies focused solely on patients with IDA (subset 1, 4 studies) was 66.6% (95% CI, 61.0%-72.3%; I2 = 44.3%); conversely, that of studies not focusing only on IDA patients (subset 2, 20 studies) was 44% (95% CI, 39%-48%; I2 = 64.9%). In particular, more vascular (31% vs 22.6%, P = .007), inflammatory (17.8% vs 11.3%, P = .009), and mass/tumor (7.95% vs 2.25%, P < .0001) lesions were detected with SBCE in patients participating in the studies in subset 1.LimitationsHeterogeneity of studies, retrospective design, and selection bias.ConclusionsThis analysis demonstrates the validity of SBCE in the investigation of patients with IDA and negative findings on a previous diagnostic workup, although certain factors such as heterogeneity and quality of the included studies should be taken into account.