Bladder pain syndrome/interstitial cystitis research takes new directions

In the most rigorous epidemiologic study of prevalence to date, the NIDDK-funded RAND Corp. population-based survey reveals a prevalence of symptoms compatible with BPS in 2.7% (high-specificity definition) to 6.7% (high-sensitivity definition) of American women (see "Up to 6% of U.S. women meet IC/PBS symptom criteria").

While no random subset of responders was subjected to urologic evaluation to confirm or refute the diagnosis, we are almost certainly faced with a much higher prevalence than heretofore considered. How many of the women who met the criteria outlined for the survey had symptoms severe or constant enough to warrant therapy is unknown.

A study from the University of Pittsburgh adds nerve growth factor to a growing list of putative markers for the syndrome (see, "Nerve growth may be marker for neurogenic OAB, IC"). This information may not only help identify these patients, but may also provide a basis for therapeutic intervention. Use of anti-nerve growth factor antibody for the treatment of pain is already a reality in phase II studies (Journal of Pain 2009; 10:s42).

Botulinum toxin is the subject of reports from Michigan and Taiwan as well as Portugal (see "New tacks in botulinum toxin show promise in IC"). The essence of these studies is that lower doses of intramural botulinum toxin may be just as efficacious as higher doses, with less morbidity and at less cost. If additional studies confirm that the intratrigonal injection procedure of Dr. Pinto further decreases morbidity while efficacy remains unchanged, the current injection procedure may well need to be modified.

Physicians would do well to keep current with this fast-moving field.

Dr. Hanno, a Urology Times editorial consultant, is professor of urology at the University of Pennsylvania, Philadelphia.