Most studies by VCE have been focused on obscure GI bleeding. The role of VCE in the assessment of other nonbleeding indications and particularly in patients with chronic diarrhea is uncertain.11 Therefore, the aim of this study is to explain the diagnostic yield and clinical impact of VCE in patients with chronic diarrhea. According to a previous study, the diagnostic yield of VCE in patients with chronic diarrhea was lower compared to obscure GI bleeding (25% vs 52%, respectively, p=0.013; CI, 1.33 to 7.83).12 In our study, the positive diagnostic yield of VCE was 42.9% (39/91). This study showed higher diagnostic yield compared with previous report (42.9% vs 25.0%).
A study regarding diagnostic tools in the evaluation of non-bleeding indications (n=165) showed the most common indications of VCE were chronic abdominal pain alone (n=33) or combined with chronic diarrhea (n=31) and chronic diarrhea alone (n=30).13 VCE findings were positive, suspicious and negative in 73 (44.2%), 13 (7.9%), and 79 (47.9%) patients, respectively. The diagnostic yields was as follows: celiac disease (100%, 10/10), suspected Crohn’s disease (83.3%, 5/6), chronic abdominal pain and chronic diarrhea (41.9%, 13/31), established Crohn’s disease (33.3%, 2/6), chronic diarrhea alone (26.7%, 8/30), chronic abdominal pain alone (24.2%, 8/33) and other indications (23.1%, 3/13) (p<0.005). Therefore, VCE is a useful tool in the evaluation of patients with nonbleeding indications. In addition, the outcome of most patients with negative findings was excellent.
In the present study, 40.7% (37/91) of patients with chronic diarrhea were ultimately diagnosed with irritable bowel syndrome. Even though VCE has no role in the diagnosis of irritable bowel syndrome, it has potential impact for the differential diagnosis of small bowel disease. Inconsistent results such as nonneoplastic polyp (6.6%), angiodysplasia (5.5%), and diverticulum (1.1%) were not associated with chronic diarrhea and should be interpreted with caution. Secondly, the most common cause of chronic diarrhea in considering evaluation for small bowel was Crohn’s disease (19.8%). The most common positive findings were erosions or aphthous ulcers (19.8%), ulcers (17.6%), mucosal erythema (3.3%), edema (1.1%), and luminal narrowing (1.1%), which were mostly suggestive of Crohn’s disease. On the contrary, some suspected Crohn’s diseases were found to be normal after VCE examination. This result was similar to a previous report as 12.5% of patients who underwent VCE (n=109) had Crohn’s disease, among all who had diarrhea (n=8).14 VCE could diagnose small bowel Crohn’s disease in nearly one third of patients with symptoms of Crohn’s inconclusive diagnosis by conventional methods.15 In this study, six suspected Crohn’s disease were ultimately diagnosed with Crohn’s disease, which was one third of 18 Crohn’s disease cases. Therefore, VCE is the most accurate diagnostic tool for detecting mucosal lesions in suspected or established Crohn’s disease, according the 2015 Korean guidelines (strong recommendations, low quality evidence).16 In our study, one patient with capsule retention had Crohn’s disease.
Some diagnoses (34.1%, 31/91) were changed according to Fig. 3. Most commonly suspected of chronic diarrhea before VCE examination were irritable bowel syndrome, Crohn’s disease, and intestinal tuberculosis in this study. However, approximately one-third (34.1%, 31/91) of diagnoses were changed following VCE examination. Therefore, VCE has a useful role in evaluating and confirming the etiology of patients with chronic diarrhea.
We analyzed factors associated with positive diagnostic yield of VCE. Interestingly, hematochezia (OR, 8.802; 95% CI, 2.126 to 36.441), and hypoalbuminemia (OR, 4.811; 95% CI, 1.241 to 18.655) are remarkable independent risk factors for predicting positive diagnostic yield according to multiple logistic regression analysis. However, weight loss, abdominal pain, anemia and positive inflammatory markers were not significant. These results were different from previous studies regarding chronic abdominal pain.9,17
Our study has some limitations. First, it was a retrospective study with various institutes; therefore, some laboratory data were not sufficient for analysis. Significant interobserver variability might exist among the gastroenterologists. The final diagnoses were also heterogeneous, it was difficult to analyze. Second, the patients included may have selection bias, because VCE was not covered by insurance during the study period (October 2002 to August 2013). Therefore, patients might have been enrolled for VCE evaluation of chronic diarrhea based on their ability to pay. Third, the period of study is too long for adequate results. Sample size may be too small to evaluate the diagnostic yield of VCE. However, this study has value as the first multicenter study regarding diagnostic yield and clinical impact of VCE in patients with chronic diarrhea based on CAPENTRY in Korea.
In conclusions, these results suggest that VCE can be helpful in patients suffering from chronic diarrhea that cannot be explained by established examinations. Overall, the positive diagnostic yield of VCE was 42.9%. After VCE, the previous diagnosis was changed in 34.1% patients (31/91). Among patients with positive findings, Crohn’s disease was the most common. VCE had favorable diagnostic yield and clinical impact in patients with chronic diarrhea. Due to the small sample size and lengthy study period, further study is recommended with larger sample and shorter study period for confirmation of results.