Importance of the natural history of benign prostatic hyperplasia in the evaluation of pharmacologic intervention

The variable natural history of untreated symptomatic benign prostatic hyperplasia (BPH) and the fact that therapeutic intervention is based more on subjective than objective criteria of progressive disease have important consequences for appropriately evaluating the effects of pharmacologic intervention on clinical BPH. To evaluate accurately the success of drug therapy for symptomatic BPH, any trial must include a placebo treatment arm for comparison. However, for such a placebo control to be legitimate, it must not affect the natural history of BPH. To evaluate the effect of placebo treatment on BPH, a large body of data following the natural history of untreated clinical BPH from a variety of independent studies was combined and compared to those from a large variety of independent studies in which a placebo‐treated group of patients with clinical BPH also followed. These comparisons demonstrate that (1) placebo treatment does not affect the natural history of the disease; (2) spontaneous improvement usually occurs within the first 6 months of initial presentation of symptoms, if it is to occur at all; and (3) 3–6 months of follow‐up are needed to determine if a patient is going to get worse. Thus, to evaluate accurately the potential benefit of any medical intervention for symptomatic BPH, placebo‐controlled clinical trials will be required and should be of at least 6 month's duration.