Effects of a standardised extract of Trifolium pratense (Promensil) at a dosage of 80mg in the treatment of menopausal hot flushes: A systematic review and meta-analysis

Objective: To critically assess the evidence for a specific standardised extract of Trifolium pratense isoflavones (Promensil) at a dosage of 80mg/day in the treatment of menopausal hot flushes.

Data sources: Systematic literature searches were performed in Medline, Scopus, CINAHL Plus, Cochrane, AMED and InforRMIT and citations obtained from 1996 to March 2016. Reference lists were checked; corresponding authors contacted and the grey literature searched for additional publications.

Review methods: Studies were selected according to predefined inclusion and exclusion criteria. All randomised clinical trials of a specific standardised extract of Trifolium pratense isoflavones (Promensil) used as a mono-component at 80mg/day and measuring vasomotor symptoms were included. The data extraction and quality assessment were performed independently by one reviewer and validated by a second with any disagreements being settled by discussion. Weighted mean differences and 95% confidence intervals were calculated for continuous data using the fixed-effects model.

Results: Twenty potentially relevant papers were identified, with only five studies meeting the inclusion criteria. The meta-analysis demonstrated a statistical and clinically relevant reduction in hot flush frequency in the active treatment group compared to placebo. Weighted mean difference 3.63 hot flushes per day: [95% CI 2.70-4.56]; p˂0.00001). Due to a lack of homogeneity a priori defined sub-group analyses were performed demonstrating a substantive difference between cross-over and parallel-arm clinical trial designs.

Conclusion: There is evidence for a statistical and clinically significant benefit for using a specific standardised extract of red clover isoflavones (Promensil) at 80mg/day for treating hot flushes in menopausal women across the 3 studies included in the meta-analysis. The preparation was safe over the short-term duration of the studies (3 months).