The wireless motility capsule (WMC) is a new modality for diagnosing gastric and colonic motility disorders. The Johns Hopkins Evidence-based Practice Center recently completed an Agency for Healthcare Research and Quality (AHRQ)-funded systematic review of the effectiveness of WMC compared with other tests of gastric and colonic motility. We also sought to define populations that would benefit most from motility testing.
Overall, the strength of evidence regarding the ability of WMC to detect gastroparesis or slow-transit constipation was graded as low. The main limitations were inconsistencies in reporting the performance of motility testing modalities. Great variability existed in administering diagnostic tests and in assessing those tests. No uniform standards define differences in diagnostic accuracy, so we arbitrarily chose a 10 percent difference in sensitivity or specificity for reference standards, such as gastric scintigraphy, and device concordance for non-reference standards, such as radiopaque markers (ROM).
Most of the “normal” subjects upon which the tests were validated were college-age men, while most of the patients with suspected gastroparesis or constipation were women over the age of 50 years. Since the population of interest comprised motility patients, we excluded studies that included only nondiseased participants.
The major strength of the review was its comprehensiveness. We reviewed abstracts, queried industry sources for unpublished studies, and contacted study authors for missing data.
WMC is comparable to other modalities in use for detecting delayed gastric emptying and slow-transit constipation. Data are insufficient to determine the optimal timing of WMC in diagnostic algorithms.
The objectives of the Future Research Needs (FRN) project were to identify the evidence gaps highlighted by the results of the systematic review and to create a set of prioritized FRN to guide stakeholders in future decisions.