The efficacy of purified pollen extract for reducing vasomotor symptoms in women: a systematic review and meta-analysis

Importance: Menopause impacts the quality of life for women, with symptoms varying from hot flashes to night disturbances. When menopausal hormonal therapy is contraindicated or women refuse menopausal hormonal therapy, many consider alternatives such as pollen extract for treating vasomotor symptoms. Objective: This meta-analysis focuses on the impact of using purified pollen extract as a treatment option to reduce vasomotor symptoms in women, specifically focusing on symptoms such as hot flashes, night disturbances, myalgias, and depression. Evidence review: A comprehensive literature search was conducted using the following Boolean search string "women OR females" AND "purified pollen OR pollen extract OR cytoplasmic pollen OR Bonafide OR Femal OR Estroven OR Serelys" AND "menopausal symptoms OR vasomotor symptoms OR hot flashes OR night sweats OR sleep disturbance." Publications in English from 2003 to the present were included. To assess the risk of bias, authors used the Cochrane Risk-of-Bias 2 for a randomized controlled trial and Risk-of-Bias in Non-Randomized Studies of Interventions (ROBINS-I) for observational studies. Using ReviewManager, a Der Simonian-Laird random-effects model meta-analysis was conducted to determine the standardized mean differences (SMDs) in the outcomes for each study. Findings: Five articles were retained: one randomized controlled trial and four observational studies ( N = 420). An overall decrease in scores from the baseline of studies compared with a 3-month follow-up after purified cytoplasm of pollen (PCP) treatment was recognized when compiling the data. Overall, there was significant improvement across all outcomes at 3 months: hot flashes demonstrated an overall improvement in SMD of -1.66 ( P < 0.00001), night disturbance scores were improved with an SMD of -1.10 ( P < 0.0001), depression scores were improved with an SMD of -1.31 ( P < 0.0001), and myalgia had an improvement in SMD of -0.40 ( P < 0.00001). When controlled studies were pooled for meta-analysis, outcomes, however, were no longer statistically significant. Conclusions and relevance: Evaluating the risk-to-benefit ratio of alternative therapies, such as PCP extract, is important to care for women who cannot take traditional vasomotor symptom therapies. Pooled data from controlled studies evaluating PCP extract suggest that vasomotor symptom improvements seen in noncontrolled studies may have been due to the placebo effect; however, its use was not associated with significant adverse effects.