Do Stool Consistency and Frequency Correlate With Total Gastrointestinal Transit Time? Results From an Italian Study in Constipated and Healthy Children

Background: Bloating and objective abdominal distention are considered gas-related symptoms and while they are related, they may represent expressions of different underlying pathophysiological process and have different response to treatment.1-2 Therefore, the efficacy of 100 mg pinaverium bromide + 300 mg simethicone (PB+S) over these symptoms, was studied in a 12-week randomized placebo-controlled trial. Methods: We studied 285 IBS-Rome III patients. They all filled-out a 12-week questionnaire that included 10-cm visual analog scales (VAS) for evaluating the intensity abdominal pain and bloating, and registered their girth circumference (objective distension) early in the morning and before bedtime during weeks 1, 6 and 12 of treatment. Data was analyzed with ANOVA for repeated measurements, using as covariate the linear combination of the girth measurements during all the weeks (explained 78% to 80% of the total variance). Finally, the abdominal volume was calculated with a mathematical model: (circumference cm)3/[6π2]. Results: Patients were 37±9 years old, F: 83%, BMI: 27±5, and were classified as IBS-C: 44%, IBS-D: 23%, IBS: 31%, and IBS-U: 2%. They reported a significant decrease in abdominal pain and bloating favoring PB+S vs. placebo (Size effect: 23% and 21% respectively, p<0.05 for both). Abdominal girth increased at night vs. morning with a mean difference of 1.8±0.2 cm, and between basal and the other weeks: 0.9±0.3 cm (Both: p<0.05). However, there were no differences in PB+S vs. placebo. Themathematical model showed difference betweenmorning and night for women: 800 mL and men: 1000 mL. The calculated abdominal volume between the basal measurement and the combination of weeks 4th and 6th were 400 mL for women and 500 mL for men. Conclusions: PB+S is effective for improving abdominal pain and bloating with no differences on objective distention. These findings suggest that BP+S may improve the gas-related symptoms through an effect on visceral perception or that measuring waist circumference is not sensitive enough to detect subtle changes in the volume of intestinal gas. Future studies should explore if distension triggers abdominal pain. 1. Chang L, et al. Am J Gastroenterol. 2001;96:3341-7. 2. Azpiroz F, Malagelada JR. Gastroenterology. 2005;129:1060-78.