Of enrolled 50 patients, 49 (98%) patients were randomized to either probiotics or a placebo for 4 weeks. One patient refused to participate in this study; 49 patients (25 in the probiotics group and 24 in the placebo group) completed the study (Fig. 1).
Table 2 shows the baseline characteristics of the participants. Age, gender, IBS subtype, intensity of abdominal pain/discomfort, bloating, stool frequency, and consistency (according to the BSFS) were not different between the two groups.
Primary Efficacy End-points
The proportion of patients who received global relief of IBS symptoms at week 4 is shown in Figure 2. There was a significantly higher response rate in the probiotics group than in the placebo group: 68.0% (17/25) versus 37.5% (9/24) (P = 0.03).
Comparison of global relief of irritable bowel syndrome (IBS) symptoms in the probiotics and placebo groups after 4 weeks of treatment. More patients in the probiotics group experienced global relief of IBS symptoms than in the placebo group: 68.0% (17/25) versus 37.5% (9/24) (P = 0.03). *P < 0.05.
Secondary Efficacy End-points
Relative to baseline, the intensity of abdominal pain (0–10 rating scale) at week 4 was significantly reduced in the probiotics group (3.2 ± 1.7→2.0 ± 1.9, P < 0.01), but not in the placebo group (3.1 ± 1.7→2.6 ± 1.4, P = 0.13) (Table 3). The intensity of abdominal discomfort and bloating was also reduced in the probiotics group but not in the placebo group. However, there was no significant difference in stool frequency and consistency between baseline and week 4 in either group. The change of abdominal pain relative to baseline was greater in the probiotics group than the placebo group, but it does not satisfy the statistical significance (−37.1 ± 46.3% vs −9.2 ± 57.1%, P = 0.07) (Table 4).
Fecal microflora was analyzed by real-time quantitative PCR to identify any alterations in intestinal microbiota after treatment with multispecies probiotics. Fecal microflora counts for each group were evaluated immediately before the start of treatment and at the end of treatment. Fecal microflora were analyzed in the 34 patients (17 each in the probiotics and placebo groups) who agreed to the collection of stool samples. Changes in the composition of fecal bacteria over the 4-week period are summarized in Table 5.
Compared with baseline, counts of B. lactis, L. rhamnosus and S. thermophilus at week 4 had increased in the probiotics group (B. lactis : 6.09 ± 1.23→7.57 ± 1.22 log10 cells/g in feces, P < 0.01; L. rhamnosus : 2.80 ± 1.69→5.05 ± 1.43, P < 0.01; S. thermophilus : 4.81 ± 0.87→5.35 ± 1.28, P = 0.04). Meanwhile placebo group showed the increase of B. lactis counts (5.99 ± 0.52→6.54 ± 0.87 log10 cells/g in feces, P = 0.04). Counts of B. longum, B. bifidum, L. acidophilus, and Escherichia coli subgroup, and Clostridium perfringens and Bacteroides group were unchanged in both groups.
Compliance and Adverse Events
The mean percentage of drugs taken to drugs prescribed was 96% in the probiotics group and 94% in the placebo group (P > 0.05). No adverse events or serious adverse events occurred in either group.
J Gastroenterol Hepatol. 2014;29(1):52-59. © 2014 Blackwell Publishing