Hi Dave:

According to this page on the incontinencenetwork site, about 75% of men with BPH will experience detrusor instability, which causes overactive bladder (OAB), a condition that causes you to feel a frequent, sudden, and sometimes intense urge to urinate. Many people have OAB without incontinence - they feel a frequent urge, but don't actually leak urine. However, in some cases people will experience leakage in conjunction with the overactive bladder. This is called urge incontinence. The treatments for BPH can also cause urge incontinence, along with stress incontinence or mixed incontinence (both stress and urge).

Unfortunately I couldn't find any very solid data about just how many men with BPH have incontinence - either before or after treatment (there may be data out there, but I couldn't find it). I do know that it is more common right after treatment, but as you heal, continence is usually regained and it is a smaller number of men who remain incontinence long-term. I also know that the rates of incontinence differ depending on the type of treatment used.

Hope this information helps! Best of luck!