Comparison of GI Transit Parameters in Functional/Idiopathic Versus Constipation Predominant Irritable Bowel Syndrome (IBS) Patients Assessed by Wireless pH/Pressure Recording Capsule

Abstract

Purpose: The SmartPill (SP) wireless pH/pressure recording capsule is utilized to assess gastric emptying (GET) small bowel transit time (SBTT) and colon transit time (CTT) in various GI motility disorders such as gastroparesis or chronic constipation (CC). Therefore, the aim of the study was to compare GET, SBTT, and CTT and whole gut transit time (WGTT) between two groups with chronic constipation: one group is diagnosed with functional (idiopathic) (FC) and another presents with IBS-C predominant symptoms, whereas a group of 39 healthy females served as the controls. Methods: In a multicenter CC study 63 constipated subjects (55 F, 8 M mean age 49 (range 21–79) were enrolled based on their Rome II criteria. 45 (73%) were identified with functional constipation (FC) and 18 (27%) had IBS-C as an etiological factor. Fasting subjects swallowed the SP capsule immediately after eating a caloric breakfast (Smart Bar, 260 kcal). They were then equipped with a recording system and diary pages were given to capture meal and symptoms status for the duration of the study. The WGTT was measured from the time of ingestion of the SP until an abrupt loss of recording signal was observed. The time from ingestion to rise of pH exceeding pH 4.0 was defined as GET and a sudden drop of 1 pH unit >5 min was regarded as ileo-cecal (I-C) arrival time. By subtracting GET from I-C time, SBTT and subsequently CTT were calculated. Based on statistical analysis with Mann-Whitney Test results are presented as median and 25–75% range. Results: The median WGTT in both CC groups was similar with 66 h (43–97 h) in FC group versus 65 h (29–119) IBS-C population (P= 0.958), which was significantly prolonged vs. normal female controls (P < 0.05) The CTT was numerically but not statistically different between FC and IBS-C patients 45 h (26–99 h) versus 58 h (20–108 h) (P= 0.802) respectively, but significantly slower then for female normal subjects (P < 0.05) The SBTT in these 2 groups of constipated patients was 4.3 h (3–5) vs. 4.0 h (3–4) (P= 0.465) and similar to results in healthy female volunteers where SBTT is <5 h. The GET in FC group 3.5 hours (3–4 h) was similar to and in IBS-C 3.4 hours (2–4 h) (P= 0.394) also within the normal limit for female controls (<5 hours. Conclusion: 1. From this study on chronic constipation in a female dominant population of patients, we conclude that WGTT and CTT are abnormally prolonged in both FC and IBS-C sub-groups of CC while GET and SBTT remain normal and are similar in both groups. 2. Although pathophysiological concepts may be different regarding the two entities, the GI transit parameters, specifically WGTT and CTT findings do not separate these two etiologies of constipation.