Table 2.
Summary of findings.
| Estimates of Effects, Confidence Intervals, and Certainty of the Evidence for Probiotics in IBS-C Patients | ||||||
|---|---|---|---|---|---|---|
| Patient or Population: IBS-C Patients Interventions: Probiotics Comparator: Placebo Setting: Hospital or No Hospital | ||||||
| Outcomes | Anticipated Absolute Effects * (95% CI) | Relative Effect (95% CI) | No. of Patients (Studies) | Certainty Of Evidence (GRADE) | Comments | |
| Risk with Placebo | Risk with Probiotics | |||||
| Abdominal pain | - | SMD 0.28 lower (0.60 lower to 0.05 higher) |
- | 488 (4 RCTs) |
⨁⨁◯◯ Low a |
There was no difference in abdominal pain in IBS-C patients treated with probiotics compared with placebo. The evidence is uncertain because randomization, allocation concealment, and blinding were inadequately reported in most of the trials; some heterogeneity (I2 was 53%). |
| Stool consistency | - | MD 0.72 higher (0.18 higher to 1.26 higher) |
- | 71 (3 RCTs) |
⨁⨁◯◯ Low b |
Probiotics could improve stool consistency scores of IBS-C patients despite study limitations (lacked sufficient details on random sequence generation and allocation concealment), and sample sizes were small (imprecision). |
| Quality of life | - | SMD 3.92 lower (8.09 lower to 0.25 higher) |
- | 487 (3 RCTs) |
⨁◯◯◯ Very Low c |
There was no difference in QoL in IBS-C patients treated with probiotics compared with placebo. The evidence is very uncertain because randomization and allocation concealment were inadequately reported; blinding was unclear; significant heterogeneity was found (I2 was 99%); and wide confidence intervals existed (lack of precision). |
| Bloating | - | SMD 0.14 lower (0.46 lower to 0.18 higher) |
- | 447 (2 RCTs) |
⨁⨁◯◯ Low a |
There was no difference in bloating in IBS-C patients treated with probiotics compared with placebo. The evidence is uncertain because there was no adequate explanation for random sequence generation, allocation concealment, or blinding; significant heterogeneity(I2 was 64%). |
| The number of Bifidobacteria in feces | - | MD 1.75 higher (1.51 higher to 2.00 higher) |
- | 38 (2 RCTs) |
⨁⨁◯◯ Low b |
Probiotics significantly increased the number of fecal Bifidobacteria despite study limitations (lacked sufficient details on random sequence generation and allocation concealment), and sample sizes were small(imprecision). |
| The number of Lactobacilli in feces | - | MD 1.69 higher (1.48 higher to 1.89 higher) |
- | 36 (2 RCTs) |
⨁⨁◯◯ Low b |
Probiotics significantly increased the number of fecal Lactobacilli despite study limitations (lacked sufficient details on random sequence generation and allocation concealment), and sample sizes were small(imprecision). |
| Adverse events | 50 per 1000 |
76 per 1000 (43 to128) |
OR 1.57 (0.87 to 2.82) |
859 (4 RCTs) |
⨁⨁◯◯ Low b |
There was no difference in adverse events in IBS-C patients treated with probiotics compared with placebo. The evidence is uncertain due to study limitations (randomization, allocation concealment, and blinding were inadequately reported), and sample sizes were small (imprecision) in most trials. |
CI: confidence interval; RCT: randomized controlled trial; SMD: standardized mean difference; MD: standardized mean difference; *: The corresponding risk (and its 95% confidence interval) is based on the relative effect of the intervention (and its 95% CI). GRADE Working Group grades of evidence: high certainty (⨁⨁⨁⨁): we are very confident that the true effect lies close to that of the estimate of the effect. Moderate certainty (⨁⨁⨁◯): we are moderately confident in the effect estimate; the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different. Low certainty (⨁⨁◯◯): our confidence in the effect estimate is limited; the true effect may be substantially different from the estimate of the effect. Very low certainty (⨁◯◯◯): we have very little confidence in the effect estimate; the true effect is likely to be substantially different from the estimate of effect. a We downgraded the quality to very low due to: serious study limitations and inconsistency. b We downgraded the quality to very low due to: serious study limitations and imprecision. c We downgraded the quality to very low due to: serious study limitations, imprecision, and heterogeneity. Certainty of the evidence expressed in the table by means of “⨁”and “◯” figures (⨁◯◯◯very low; ⨁⨁◯◯Low).