Lower urinary tract symptoms, benign prostatic obstruction and the overactive bladder.

Lower urinary tract symptoms (LUTS), benign prostatic obstruction (BPO), and the overactive bladder have increasing prevalence with age in both men and women (with the obvious exception). The question is, are they interrelated or independently related to age? The specific issue is whether BPO causes the overactive bladder. There are two pieces of evidence that might appear to suggest such a cause and effect. First, the overactive bladder is more common in men than in women of the same age, although physiologically, men are 5-10 years older at the same biological age. Second, the overactive bladder resolves in two-thirds of individuals after surgical interventions such as transurethral prostatectomy. The symptoms suggestive of an overactive bladder are the most troublesome, even though they may not be the most prevalent. Long-term follow-up studies with repeated urodynamic investigations have shown that the incidence of the overactive bladder and its attendant symptoms increases despite there being no deterioration in outlet obstruction over follow-up periods of 10 and 20 years. These data, and others, indicate that the situation is not as straightforward as some believe. The statement that 'the overactive bladder is secondary to BPO' cannot be made, as there are too many unanswered questions and pieces of the puzzle that do not fit. The overactive bladder is undoubtedly associated with BPO, and it leads to the most troublesome LUTS in older men. Epidemiological research, coupled with urodynamic evaluation, may provide further evidence. We also need better and more relevant models (e.g. ageing animals), together with further histological and other biological data before the waters become crystal clear.