The role of placebo and nocebo effects in randomized trials concerning pharmacological treatment of benign prostatic hyperplasia
Article published in Urologia Polska 2004/57/4.
Jakub Dobruch 1, Andrzej Borówka 1, Piotr Chłosta 2, Artur A. Antoniewicz 1
- 1 Klinika Urologii Centrum Medycznego Kształcenia Podyplomowego, I Zespół Dydaktyki Urologicznej – Oddział Urologii Centralnego Szpitala Kolejowego w Warszawie
Kierownik kliniki i ordynator oddziału: prof. dr hab. Andrzej Borówka
2 Dział Urologii ¦więtokrzyskiego Centrum Onkologii w Kielcach
Kierownik działu: dr med. Stefan Olszewski
prostate, benign prostatic hyperplasia (BPH), placebo effect, nocebo effect, randomized trials (RCT)
- introduction and objectives
- Nonspecific effects not associated with drugs characteristics are always involved in obtaining positive and also negative outcomes of pharmacological treatment. These, are known as placebo and nocebo effects respectively. Every new method of therapy including drugs used in the treatment of men with benign prostatic hyperplasia (BPH) needs to be evaluated as far as its clinical usefulness is concerned. To this end randomized, placebo controlled trials (RCT) are designed and performed. Their results are used to compare efficacy and safety of analyzed drug with placebo.
- materials and methods
- The purpose of the study was to evaluate the role of placebo and nocebo effects in randomized trials concerning pharmacological treatment of benign prostate hyperplasia. Results of randomized, placebo controlled trials concerning efficacy and safety of a-adrenergic blocking drugs and finasteride in the treatment of BPH were analyzed. The placebo effect was estimated based on lower urinary tract symptoms (LUTS – lower urinary tract symptoms) severity, maximal urinary flow (Qmax – peak urinary flow), residual volume of urine (Rv – residual volume) and prostate volume (Pv – prostate volume). Lower urinary tract symptoms severity was assessed using well known questionnaires (Madsen-Iversen, Boyarsky, American Urological Association Symptom Index – AUA-SI, International Prostate Symptom Score – I-PSS). Placebo effect was presented as percent change of mentioned above parameters comparing final and initial values. Nature and frequency of observed side effects and percentage of men who discontinued the study were also evaluated.
- Results of trials concerning the role of a-adrenergic blocking drugs in the treatment of BPH revealed that LUTS severity declined about 1-58%, Qmax increased about 4-46% and changes of Rv ranged between -13,4% and +8,4% in the placebo group. Placebo effects intensity was slightly less expressed in finasteride trials: LUTS severity declined about 4-19%, Qmax increased about 0-14%, Pv increased about few percent (from -8.2% to 28%), and data regarding Rv were usually unavailable. Placebo usage was not free from adverse effects. They were demonstrated by 6-81% of men. 5-10% of men discontinued the study because of adverse effects.
- Placebo effect was observed in every study but its intensity varried a lot. It was best expressed in referrence to LUTS severity and observed particularly in the first three months of treatment. Improvement of Qmax was present for shorter period of time, whereas decrease of Rv as a result of placebo therapy was negligible similarly to prostate volume. Side effects were presented by 6.8-81% of men in both with active and inactive drug groups of treatment.
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