U.S. Department of Health and Human Services pdf Wireless Motility Capsule Versus Other Diagnostic Technologies for Evaluating Gastroparesis and Constipation: Future Research Needs: Future Research Needs Paper Number 27

Gastroparesis delays gastric emptying without a physical blockage. Its symptoms are nausea, vomiting, early satiety, bloating, abdominal pain, and postprandial fullness. Its prevalence is estimated to be 9.6 per 100,000 among men and 37.8 per 100,000 among women. Between 1.5 and 3 million Americans are affected. Related hospitalizations increased by 158% between 1995 and 2004. Evaluation may employ gastric emptying scintigraphy, antroduodenal manometry, and the wireless motility capsule (WMC) – and it guides nutritional, medical, and surgical therapies. Constipation is common, occurring in 15 to 20% of the population. It is defined as fewer than two bowel movements per week, or a decrease in a person’s normal frequency accompanied by straining, difficulty defecating, or passage of hard stools. Patients with slow transit constipation often have severe symptoms, with prolonged intervals between bowel movements, and may be refractory to standard therapies. Prevalence of slow-transit constipation is 0.03–0.17%. For patients with refractory symptoms, colonic physiology testing may include radiopaque markers (ROM), colonic scintigraphy, manometry, and the WMC. The 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-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% difference in sensitivity or specificity for reference standards, such as gastric scintigraphy, and device concordance for non-reference standards, such as 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. Evidence gaps were identified in the review writing process based on the strength of evidence, applicability, and limitations of the review. Individuals who contributed to review writing met multiple times and circulated by email lists of potential questions to identify gaps. This process developed a list of research gaps to be presented to the stakeholders.