A Relevant Midterm (12 Months) Placebo Effect on Lower Urinary Tract Symptoms and Maximum Flow Rate in Male Lower Urinary Tract Symptom and Benign Prostatic Hyperplasia—A Meta-analysis

Abstract

To assess the mid- to long-term placebo effect of the medical and instrumental management of male lower urinary tract symptoms. This is generally a long-term treatment strategy. Therefore, knowledge on the mid- to long-term placebo effect is of considerable interest. The paucity of data on this topic prompted us to investigate this issue in a meta-analysis. All randomized controlled trials (RCTs) with the indication of benign prostatic hyperplasia and lower urinary tract symptoms containing a placebo- or sham treatment arm and with a follow-up of 12 months were eligible. The 12-month effect of placebo or sham treatment on the International Prostate Symptom Score (the quality-of-life question was not analyzed herein) and the American Urological Association Symptom Score and on the maximum flow rate was quantified. A total of 25 RCTs with 10.587 patients were eligible. Twenty-three studies were placebo controlled (plant extracts: n = 4, 5α-reductase inhibitors [5ARIs]: n = 9, α-blocker: n = 5, combination therapy of 5ARI and α-blocker: n = 3, and intraprostatic botulinum toxin A injection: n = 2), and 2 RCTs with transurethral microwave thermotherapy (TUMT) had a sham treatment arm. At 12 months, the mean International Prostate Symptom Score improved by a mean of 4.4 points under placebo or sham treatment with a range of 0.7-6.8 points: plant extracts, -3.6; 5ARI, -3.4; α-blocker, -4.3; combination therapy, -4.3; botulinum toxin A, -3.9; and TUMT, -6.8. The mean maximum flow rate improvement at 12 months under placebo or sham was not relevant (+0.8 mL/s), yet there were remarkable differences between trials: plant extracts, -0.3 mL/s; 5ARI, +0.8 mL/s; α-blocker, +1.1 mL/s; combination therapy, +1.4 mL/s; and TUMT, +1.0 mL/s. This meta-analysis demonstrates the mid-term placebo effect on lower urinary tract function, particularly concerning subjective improvement. The degree of the placebo effect varies considerable between studies even at 12 months.