A Review of Prostatitis

To the Editor A recent Review on prostatitis correctly noted that important chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) clinical trials were powered using at least a 4-point decrease in the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI) total score. A meta-analysis estimated the placebo response in CP/CPPS at −4.2 (95% CI, −6.31 to −2.09). This information should be communicated to patients and clinicians because it might be useful in the shared decision-making process about potential treatments. A systematic review and meta-analysis that included 35 randomized clinical trials of patients with CP/CPPS demonstrated that for every additional week of any given treatment for CP/CPPS, the total NIH-CPSI score decreased by a mean of 0.19 points. These findings imply that 32 weeks of treatment would be required to achieve an NIH-CPSI score reduction of 6 points, which constitutes the conventionally accepted minimum clinically important difference. Although the exact magnitude and duration of the placebo response in CP/CPPS are unknown, the placebo effect does not appear to change over time.