Objectives: To systematically review the evidence comparing wireless motility capsule (WMC) with other diagnostic tests used for the evaluation of gastroparesis and slow-transit constipation, in terms of diagnostic accuracy, accuracy of motility assessment, effect on treatment decisions, effect on patient-centered outcomes, harms, and effect on resource utilization.
Data sources: We searched Medline ® and Embase ® from inception through July 2012. Additionally, we scanned reference lists of relevant articles and queried experts.
Review methods: We included studies in any language that compared WMC with other diagnostic tests among patients with suspected gastroparesis or slow-transit constipation. Two reviewers independently assessed articles for eligibility, serially abstracted data from relevant articles, independently evaluated study quality, and graded the strength of the evidence (SOE). We summarized results qualitatively rather than quantitatively because of the heterogeneity of studies.
Results: We included 12 studies (18 publications). Seven studies evaluated diagnosis of gastric emptying delay; we found low SOE that WMC alone was comparable to scintigraphy for diagnostic accuracy, accuracy of motility assessment, effect on treatment decisions, and effect on resource utilization. Sensitivity of WMC compared with gastric scintigraphy ranged from 59 to 86 percent and specificity ranged from 64 to 81 percent. We found two studies evaluating WMC as an add-on to other testing. The SOE was low for diagnostic accuracy and for the accuracy of motility assessment by WMC in combination with other modalities. The addition of WMC increased diagnostic yield. Nine studies analyzed colon transit disorders and provided moderate SOE for diagnostic accuracy, accuracy of motility assessment, and harms. WMC was comparable to radiopaque markers (ROM), with concordance ranging between 64 percent and 87 percent. Few harms were reported. The evidence was insufficient to justify conclusions about effects of WMC on treatment decisions and resource utilization.
Conclusions: WMC is comparable in accuracy to current modalities in use for detection of slow-transit constipation and gastric emptying delay, and is therefore another viable diagnostic modality. Little data are available to determine the optimal timing of WMC for diagnostic algorithms.