Validation of Diagnostic and Performance Characteristics of the Wireless Motility Capsule in Patients With Suspected Gastroparesis

Abstract

Background & aims: It is a challenge to make a diagnosis of gastroparesis. There is good agreement in results from wireless motility capsule (WMC) analysis and gastric emptying scintigraphy (GES), but the diagnostic yield of WMC is unclear and the accuracy of this method has not been validated. We compared the performance characteristics of WMC vs GES in assessing gastric emptying in patients with suspected gastroparesis.

Methods: We performed a prospective study of 167 subjects with gastroparesis (53 with diabetes and 114 without) at 10 centers, from 2013 through 2016. Subjects were assessed simultaneously by GES and with a WMC to measure gastric emptying and regional transit. Delayed gastric emptying by GES was defined as more than 10% meal retention at 4 hrs whereas delayed gastric emptying by WMC was defined as more than 5 hrs for passage of the capsule into the duodenum; a severe delay in gastric emptying was defined as a gastric emptying time of more than 12 hrs by WMC or more than 35% retention at 4 hrs by GES. Rapid gastric emptying was defined as less than 38% meal retention at 1 hr based on by GES or gastric emptying times less than 1:45 hrs by WMC. We compared diagnostic and performance characteristics of GES vs WMC.

Results: Delayed gastric emptying was detected in a higher proportion of subjects by WMC (34.6%) than by GES (24.5%) (P=.009). Overall agreement in results between methods was 75.7% (kappa=0.42). In subjects without diabetes, the WMC detected a higher proportion of subjects with delayed gastric emptying (33.3%) than GES (17.1%) (P < .001). A higher proportion of subjects with diabetes had delayed gastric emptying detected by GES (41.7%) compared with non-diabetic subjects (17.1%) (P=.002). Severe delays in gastric emptying were observed in a higher proportion of subjects by WMC (13.8%) than by GES (6.9%) (P = .02). Rapid gastric emptying was detected in a higher proportion of subjects by GES (13.8%) than by WMC (3.3%) (P < .001). Regional and generalized transit abnormalities were observed in 61.8% subjects and only detected by WMC.

Conclusion: Although there is agreement in analysis of gastric emptying by GES vs WMC, WMC provides higher diagnostic yield than GES. WMC detects delayed gastric emptying more frequently than GES and identifies extra-gastric transit abnormalities. Diabetic vs non-diabetic subjects have different results from GES vs WMC. These findings could affect management of patients with suspected gastroparesis. ClinicalTrials.gov no: NCT02022826.

Keywords: Colonic Transit; Gastrointestinal Motility; Idiopathic; Small Bowel Transit.

Figure 1.

a) Overall, there was a significantly higher rate of delayed gastric emptying detected by GET (dark blue) when compared to GES (light blue) (34.6% vs. 24.5%, p=0.009). In non-diabetic subjects, WMC detected significantly more subjects with delayed gastric transit when compared to GES (33.3% vs. 17.1%, p<0.001). In diabetic subjects, there were no differences in rates of delayed gastric emptying by GES and GET (37.2% vs. 41.7%, p=0.48). b) Diabetic subjects (light green) were more likely to have delayed gastric emptying detected by GES when compared to non-diabetic subjects (dark green) (41.7% vs. 17.1%, p=0.002). However, there were no differences in rates of delayed gastric emptying by WMC between diabetic and non-diabetic subjects.

Figure 2.

There were significantly higher rates of rapid gastric emptying with GES (light blue) when compared to GET (dark blue) in all subjects (13.8% vs. 3.3%, p<0.001). In non-diabetic subjects, a higher number of subjects showed rapid gastric emptying with GES compared to WMC (11.7% vs. 0.9%, p<0.001). In diabetic subjects, there were no differences in detection of rapid gastric emptying by GES compared with GET (18.4% vs. 9.3%, p=0.16). WMC was more likely to detect rapid gastric emptying in diabetics compared with non-diabetic subjects (9.3% vs. 0.9%, p=0.02). However, there were no differences in rapid gastric emptying by GES in diabetics vs. non-diabetics.

Figure 3.

(A) Delayed SBTT was noted in 22.8% of all subjects (light blue) including 12.5% of diabetic (dark blue) and 26.6% of non-diabetic subjects (green) (p=0.07). Delayed CTT was seen in 31.5% of all subjects including 32.5% of diabetics and 31.2% of non-diabetic subjects. Generalized transit delays were found in 21.1% of subjects including 12.5% of diabetics and 24.8% of non-diabetic subjects (p=0.11). p-values are comparing diabetics with non-diabetics. (B) Delayed GES (light blue) was seen in 24.5% while delayed GET (dark blue) was detected in 34.6%. Delayed GET±SBTT (light green) was found in 45.8%, GET±CTT (dark green) in 52.9%, SBTT±CTT (pink) in 46.3% and overall any delay by WMC (red) was detected in 61.8%.