TABLE 11.
Anticipated absolute effects2 (95% CI) | ||||||
---|---|---|---|---|---|---|
Outcomes | Risk with placebo or usual treatment | Risk with butyrate | Relative effect (95% CI) | Number of participants (studies) | Certainty of the evidence (GRADE) | Comments |
Fasting blood glucose | — | MD = −1.20 (−2.91 to 0.51) | — | 30 (1 RCT) | 2 Very low3 | The evidence is very uncertain about the effect of butyrate on fasting blood glucose, as there is only 1 study on chronic butyrate that fit our criteria |
Fasting insulin | — | MD = 0.9 (0.57–1.31) | — | 30 (1 RCT) | 2 Very low3 | The evidence is very uncertain about the effect of butyrate on fasting insulin, as there was only 1 study investigating butyrate that fit our criteria |
In the GRADE working group grades of evidence, very low certainty indicates we have very little confidence in the effect estimate: the true effect is likely to be substantially different from the estimate of effect. Abbreviations: GRADE, Grading of Recommendations, Assessment, Development, and Evaluation; MD, mean difference; RCT, randomized controlled trial; T2D, type 2 diabetes.
The risk in the intervention group (and its 95% CI) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI).
The risk of bias was high due to a lack of blinding, incomplete accounting of patients and outcome events, and selective outcome reporting. Publication bias is suspected, as there is only 1 study investigating butyrate, which demonstrates butyrate has a significant effect.