Objectives: Capsule endoscopy (CE) allows for direct evaluation of the small bowel mucosa in patients with Crohn's disease (CD). A number of studies have revealed significantly improved yield for CE over other modalities for the diagnosis of CD, but as sample sizes have been small, the true degree of benefit is uncertain. Additionally, it is not clear whether patients with a suspected initial presentation of CD and those with suspected recurrent disease are equally likely to benefit from CE. The aim of this study was to evaluate the yield of CE compared with other modalities in symptomatic patients with suspected or established CD using meta-analysis.
Methods: We performed a recursive literature search of prospective studies comparing the yield of CE to other modalities in patients with suspected or established CD. Data on yield among various modalities were extracted, pooled, and analyzed. Incremental yield (IY) (yield of CE--yield of comparative modality) and 95% confidence intervals (95% CI) of CE over comparative modalities were calculated. Subanalyses of patients with a suspected initial presentation of CD and those with suspected recurrent disease were also performed.
Results: Nine studies (n = 250) compared the yield of CE with small bowel barium radiography for the diagnosis of CD. The yield for CE versus barium radiography for all patients was 63% and 23%, respectively (IY = 40%, p < 0.001, 95% CI = 28-51%). Four trials compared the yield of CE to colonoscopy with ileoscopy (n = 114). The yield for CE versus ileoscopy for all patients was 61% and 46%, respectively (IY = 15%, p= 0.02, 95% CI = 2-27%). Three studies compared the yield of CE to computed tomography (CT) enterography/CT enteroclysis (n = 93). The yield for CE versus CT for all patients was 69% and 30%, respectively (IY = 38%, p= 0.001, 95% CI = 15-60%). Two trials compared CE to push enteroscopy (IY = 38%, p < 0.001, 95% CI = 26-50%) and one trial compared CE to small bowel magnetic resonance imaging (MRI) (IY = 22%, p= 0.16, 95% CI =-9% to 53%). Subanalysis of patients with a suspected initial presentation of CD showed no statistically significant difference between the yield of CE and barium radiography (p= 0.09), colonoscopy with ileoscopy (p= 0.48), CT enterography (p= 0.07), or push enteroscopy (p= 0.51). Subanalysis of patients with established CD with suspected small bowel recurrence revealed a statistically significant difference in yield in favor of CE compared with all other modalities (barium radiography (p < 0.001), colonoscopy with ileoscopy (p= 0.002), CT enterography (p < 0.001), and push enteroscopy (p < 0.001)).
Conclusions: In study populations, CE is superior to all other modalities for diagnosing non-stricturing small bowel CD, with a number needed to test (NNT) of 3 to yield one additional diagnosis of CD over small bowel barium radiography and NNT = 7 over colonoscopy with ileoscopy. These results are due to a highly significant IY with CE over all other modalities in patients with established non-stricturing CD being evaluated for a small bowel recurrence. While there was no significant difference seen between CE and alternate modalities for diagnosing small bowel CD in patients with a suspected initial presentation of CD, the trend toward significance for a number of modalities suggests the possibility of a type II error. Larger studies are needed to better establish the role of CE for diagnosing small bowel CD in patients with a suspected initial presentation of CD.