PRACTICE CHANGER
Advise men with benign prostatic hyperplasia (BPH) not to take saw palmetto for urinary symptoms. Explain that it has not been found to alleviate symptoms, even at triple the standard dose.1
A: Based on evidence from a high-quality randomized controlled trial (RCT)1 and a 2009 meta-analysis.2
1. Barry MJ, Meleth S, Lee JY, et al. Effect of increasing doses of saw palmetto extract on lower urinary tract symptoms: a randomized trial. JAMA. 2011;306:1344-1351.
ILLUSTRATIVE CASE
A 66-year-old man comes to your office complaining of urinary frequency and straining to begin urination. He was recently diagnosed with BPh by a urologist, but is hesitant to begin taking a prescription drug. The patient, who is on a fixed income, asks you if saw palmetto extract might relieve his urinary symptoms. What should you tell him?
Roughly 40% of American men older than 60 years and nearly 90% of men older than 80 suffer from BPH and the troublesome lower urinary tract symptoms (LUTS) that it causes.3 Established medical and surgical options, as well as over-the-counter (OTC) plant-based products, are used for symptom relief. The OTC remedy most commonly used for BPH is Serenoa repens, derived from the saw palmetto dwarf palm tree. In a 2007 survey, 1.6 million US adults reported using saw palmetto extract, often as a treatment for BPH, in the 30 days prior to the survey.4
Until now, more questions than answers
As a family physician, you undoubtedly have many patients who are taking or considering taking saw palmetto for relief of BPH symptoms. The significant adverse effects of alpha-blockers and 5-alpha-reductase inhibitors, which are typically prescribed for LUTS—including decreased libido and dizziness—may help account for their interest in this alternative treatment.5,6
Until recently, evidence of saw palmetto’s efficacy has been limited and conflicting, despite widespread use of the extract. That has left many of us wondering whether we should recommend that men with BPH try saw palmetto despite the limited evidence; whether it is effective for some, but not all, BPH symptoms; and whether an increase in dose would increase its efficacy.
A 2002 Cochrane meta-analysis of 21 trials of saw palmetto extract for LUTS reported reduced nocturia, improved self-reported symptoms, and increased peak uroflow compared with placebo, without significant adverse effects.7 An updated Cochrane review published in 2009 included several more rigorous trials—and had very different results: This meta-analysis, which was based on 30 trials, found a reduction in nocturia, but failed to show improvement in other self-reported symptoms or peak uroflow.2
The largest trial included in the 2009 review was the Saw Palmetto Treatment for Enlarged Prostates (STEP) study,8 a one-year study with 225 participants. Its findings: no improvement in the treatment group compared with the placebo group in symptom scores or any secondary endpoints, and no important toxicity.8 Of note, the STEP study and most trials included in the 2009 Cochrane review used the standard saw palmetto extract dose of 160 mg twice daily.1,2
STUDY SUMMARY: Saw palmetto is ineffective, even at triple the dose
Barry et al conducted a 72-week double-blind, multicenter placebo-controlled trial to assess the effect of double (640 mg/d) and triple (960 mg/d) the standard dose of saw palmetto extract on BPH symptoms.1 The study included 369 men with moderate LUTS who had not recently received treatment for BPH. Exclusion criteria included a history of invasive BPH treatment, recent treatment with either an alpha-blocker or a 5-alpha-reductase inhibitor; recent phytotherapy, including saw palmetto; and a history of prostate or bladder cancer. Participants were randomized to receive either saw palmetto extract or an identical-looking placebo gel cap. Doses started at 320 mg/d and were increased to 640 mg/d at 24 weeks and 960 mg/d at 48 weeks.
The primary outcome was the change in the American Urological Association Symptom Index (AUASI) score from baseline to 72 weeks. AUASI, a scale of 0 to 35 in which higher numbers represent increased symptoms, is the same scoring tool used in both the Cochrane review and the STEP trial. Secondary measures included other symptom scales, peak uroflow, and poststudy satisfaction. The treatment and placebo groups had statistically identical baseline characteristics, and the sample size was large enough to detect clinically significant differences.
The AUASI score decreased by a mean of 2.20 points (95% confidence interval [CI], -3.04 to -0.36) in the group that received saw palmetto and by 2.99 points (95% CI, -3.81 to -2.17) in the placebo group—a mean difference of 0.79 in favor of the placebo group (P=.91). The proportion of participants achieving a 3-point reduction in AUASI score was statistically similar between the 2 groups (P=0.66). There was no significant dose response difference between the 2 groups, and saw palmetto proved to be no better than placebo for any of the secondary outcomes.