To determine what proportion of patients with recent-onset interstitial cystitis (IC)/painful bladder syndrome (PBS) met the International Continence Society (ICS) definition and how those who met the definition differed from those who did not.

We recruited women who had recent-onset IC/PBS for an ongoing case-control study to identify its risk factors and studied our first 138 eligible patients to identify those who met the ICS definition. We then compared those who met the definition with those who did not by variables acquired from interviews and medical records.

The 138 participants had intensities of pain, urgency, frequency, and nocturia, as well as O’Leary-Sant Symptom Index scores, similar to those of previously reported patients with IC/PBS. Six percent of cystoscopies demonstrated Hunner’s ulcers, and 89% of hydrodistensions under anesthesia revealed glomerulations. The most liberal interpretation of the ICS definition did not include 47 (34%) of our patients. Comparing these with the 91 (66%) who did meet the ICS criteria, we found that 96 of 97 clinical variables, including many generally thought to be characteristic of IC/PBS, were not significantly different between the two groups.

The ICS definition identified only 91 (66%) of the 138 patients whom study investigators and caregivers diagnosed as having IC/PBS. Furthermore, those who met the ICS definition did not differ in important ways from those who did not. These observations taken together suggest that the ICS definition may not be sufficiently sensitive. Minor modifications of the definition appeared to increase its sensitivity. Validation of a case definition (ie, assessing its sensitivity and specificity) would require testing it in patients with IC/PBS, as well as in patients with other diseases with similar symptoms.