Randomized controlled trial of probiotics after colonoscopy

Up to 20% of patients have ongoing abdominal symptoms at day 2 and beyond following colonoscopy. It was hypothesized that some of these symptoms are related to alterations in gut microbiota secondary to bowel preparation and would improve with probiotics compared with placebo.

Patients were given either a probiotic or placebo capsule in the days following colonoscopy. Colonoscopy was performed with air insufflation. The probiotic capsule contained the strains Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07. Patients recorded their symptoms at 1 h, 1, 2, 4, 7 and 14 days post colonoscopy and returned results once their symptoms had resolved. The primary outcomes used were the length of days to resolution of bloating, abdominal pain and altered bowel function post colonoscopy.

A total of 320 patients were randomized. After loss to follow-up and withdrawal, 133 patients were analysed in the probiotic group and 126 in the placebo group. Patients having probiotic had a lower number of pain days following colonoscopy, 1.99 versus 2.78 days (P < 0.033). There was no significant difference in bloating or return to normal bowel habit days (P = 0.139 and 0.265 respectively). Subgroup analysis revealed that patients with pre-existing abdominal pain benefited from probiotics in number of pain days, 2.16 versus 4.08 (P = 0.0498).

Our study has shown a significant reduction in the duration of pain days post colonoscopy in patients taking probiotic compared with placebo. No significant effect was seen in terms of return to normal bowel function or bloating post colonoscopy.