Understanding "Remains Statistically Significant" in the Context of Finasteride Sexual Side Effects
"Remains statistically significant" means that even though the sexual dysfunction associated with finasteride decreased in severity over time, the difference between the finasteride group and placebo group was still mathematically detectable and unlikely to be due to chance—but this does NOT mean the side effects persisted in individual patients after stopping the drug. 1
What This Actually Means
The phrase from the ASCO/AUA guideline is describing on-treatment data, not post-discontinuation persistence:
- Sexual dysfunction decreased over time while men continued taking finasteride
- The difference between finasteride and placebo groups remained detectable statistically throughout the study period
- The clinical magnitude was small: only 3.21 points difference on a 0-100 scale, compared to 1.26 points for each year of aging 1
Critical Distinction: During Treatment vs. After Stopping
During Treatment (What the Guidelines Address)
The FDA label and ASCO/AUA guidelines show that during active treatment:
- Year 1: Higher rates of sexual dysfunction (8.1% impotence vs 3.7% placebo)
- Years 2-4: Rates equalized between groups (5.1% vs 5.1%) 2
- This means the side effects largely resolved even while continuing the medication
After Discontinuation (Post-Finasteride Syndrome Claims)
The evidence here is dramatically weaker and conflicting:
Supporting persistence:
- Small observational studies report persistent dysfunction in self-selected populations 3, 4
- FDA label updated to include reports of "sexual dysfunction that continued after discontinuation" 2
- These are post-marketing reports with significant methodological limitations
Against persistence as a widespread phenomenon:
- The nocebo effect accounts for substantial reporting: 43.6% sexual dysfunction when informed of side effects vs 15.3% when not informed 5
- FAERS database analysis shows disproportionate reporting spike after 2012 when "post-finasteride syndrome" awareness campaigns began 6
- Most controlled trials show no persistent effects after discontinuation
Clinical Bottom Line
The phrase "remains statistically significant" refers to the mathematical detectability of a small difference between treatment groups during active therapy—NOT to individual patients having permanent side effects. The actual clinical picture shows:
- Most sexual side effects during treatment are mild and resolve even with continued use 1, 2
- The magnitude is clinically trivial (3.21 points vs 1.26 points per year of aging) 1
- Post-discontinuation persistence is reported but heavily confounded by nocebo effects, selection bias, and awareness campaigns 5, 6
Key Pitfall to Avoid
Do not conflate "statistically significant" with "clinically meaningful" or "persistent after stopping." Statistical significance only means the finding is unlikely due to chance—it says nothing about magnitude, clinical relevance, or duration after treatment cessation.