A systematic review with meta-analysis «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 compared peppermint oil with placebo and found a favorable effect on global IBS symptoms and abdominal pain with peppermint oil. However, the results were inconsistent, and dichotomized outcomes decreased the interpretability of clinical relevance.
According to the results from the most recently published two randomized, controlled trials «Weerts ZZRM, Masclee AAM, Witteman BJM, et al. Eff...»2, «Nee J, Ballou S, Kelley JM, et al. Peppermint Oil ...»3, no significant differences were seen in primary efficacy endpoints between peppermint oil and placebo.
| Reference | Study type | Population | Intervention and comparison | Outcomes | Risk of bias |
|---|---|---|---|---|---|
| RCT=randomized controlled trial; SR=systematic review; MA=meta-analysis | |||||
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 | SR/MA; 10 RCTs, 1030 patients |
Patients 18 years or older, with a diagnosis of IBS based on clinician's opinion or specific diagnostic criteria. Minimum duration of therapy 4 weeks. | Peppermint oil or placebo (525/505) | Primary: Proportion of patients failing to achieve an improvement in global IBS symptoms and/or abdominal pain | High |
| Reference | Comments |
|---|---|
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 | Individual studies had differing definitions of IBS, mostly small sample sizes, short
duration of treatment (4-12 weeks), different peppermint oil preparations used (small
intestine-relase peppermint oil, ileocolonic-release peppermint oil) High risk of bias due to high dropout rates and incomplete reporting of allocation concealment. Furthermore, unblinding likely due to smell/taste of peppermint oil. Secondary outcomes: number of people with any adverse event or gastro-oesophageal reflux symptoms |
Results
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) C | Relative effect (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: very low The quality of evidence it was limited by study limitations, imprecision and inconsistency. I=intervention; C=comparison; CI=confidence interval |
|||||
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 | 10 RCTs 1 030 patients (I525, C 505) |
4-12 weeks | 285 (54.3 %) | 365 (72.3 %) | RR 0.65 (0.47;0.88) |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) C | Relative effect (95% CI) |
|---|---|---|---|---|---|
| Level of evidence: very low The quality of evidence it was limited by study limitations, imprecision and inconsistency. I=intervention; C=comparison; CI=confidence interval |
|||||
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 | 7 RCTs 756 patients (I388, C 368) |
4-12 weeks | 217 (55.9 %) | 259 (70.4 %) | RR 0.65 (0.43;0.98) |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) C | Relative effect (95% CI) |
|---|---|---|---|---|---|
| I=intervention; C=comparison; CI=confidence interval | |||||
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 | 7 RCTs 748 patients (I383, C 365) |
4-8 weeks | 181 (47.3 %) | 218 (59.7 %) | RR 0.76 (0.62;0.93) |
| Reference | Number of studies and number of patients (I/C) | Follow-up time | Absolute number of events (%) I | Absolute number of events (%) CS | Relative effect (95% CI) |
|---|---|---|---|---|---|
| I=intervention; C=comparison; CI=confidence interval | |||||
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 Any adverse event |
7 RCTs 720 patients (I340, C 380) |
4-12 weeks | 58 (17.1 %) | 46 (12.1 %) | RR 1.57 (1.04;2.37) |
| «Ingrosso MR, Ianiro G, Nee J, et al. Systematic re...»1 Gastro-oesophageal reflux symptoms |
8 RCTs 973 patients (I465, C 444) |
4-12 weeks | 83 (17.9 %) | 34 (7.7 %) | RR 1.67 (1.18;2.38) |