The Placebo Effect in the Pharmacologic Treatment of Patients with Lower Urinary Tract Symptoms

ObjectivesWe reviewed placebo responses in randomised controlled trials (RCTs) for pharmacologic treatment of lower urinary tract symptoms (LUTS), including urinary incontinence (UI), overactive bladder, and benign prostatic hyperplasia. Review papers on placebo effects in non-urologic disorders were assessed to compare the magnitude of placebo responses in drugs for LUTS with those reported for other diseases.MethodsData were retrieved from registration trials for LUTS drugs on the Web sites of the Food and Drugs Administration and the European Medicines Agency. Reviews were retrieved from Medline using the MeSH term “placebo effect” (English language; published between 1990 and 2005).ResultsPlacebo treatment of LUTS yields reductions in incontinence episodes (IEs) ranging from 32% to 65%, whereas prostate or UI symptom scores are reduced by 9–34%. Genuine drugs decrease IEs by 45–77% and symptom scores by 22–45%. Placebo responses are much lower when objective changes in voided volume or peak flow rate are assessed.ConclusionsThe placebo effect in LUTS has a strong behavioural component as patients become aware of their voiding habits and potential risk factors. Symptom severity, treatment naivety, study duration, and interaction with health care providers may also influence it. Proper patient selection, study duration, and objective and subjective outcome measures may better separate genuine treatment effects from artefacts. Observational studies with patients representative for real-life situations and covering a sufficient period of time could allow for better understanding of RCT results and their applicability in clinical practice.