National Institute of Diabetes & Digestive & Kidney Diseases

1. Interstitial cystitis is a symptomatic diagnosis based on the presence of three key symptoms: pain, urgency, and frequency, as well as exclusion of a short list of other conditions that cause the same symptoms.
   1. Pain is the most consistent and disabling symptom for IC patients. Some will not use the term pain, but will rather describe a sense of pressure or discomfort. Typically, but not always, the pain is worse with filling of the bladder and is relieved by emptying the bladder.
   2. Urgency in IC patients differs from that experienced by patients with urinary incontinence. In IC patients, the urgency is driven by pain; in patients with incontinence, it is driven by their fear of losing control.
   3. Not enough information is available on normal variability of urinary frequency to establish a number that can help diagnose IC.


2. NIDDK criteria for IC were developed to select a set of patients for clinical trials. Many patients whom experienced clinicians would agree have IC do not meet these criteria; therefore; they are too selective and not useful for epidemiological studies. There is no “gold standard” for diagnosis, and criteria used by experienced clinicians will need standardization for use in epidemiology studies.



3. Questions to subjects about whether or not they have ever been given the diagnosis of IC are not useful because subjects frequently confuse the term interstitial cystitis with acute bacterial cystitis.



4. The prevalence of symptoms consistent with diagnosis is much higher than the rate of clinician diagnosis. Subjects identified through clinician offices will differ from subjects identified through population sampling strategies.

1. Use a population-based sampling strategy to identify persons who are symptomatic. An example of this type of strategy is the one used by the Chronic Fatigue Syndrome Research Program of the Centers for Disease Control and Prevention. The scope of research should include persons with symptoms consistent with either interstitial cystitis or painful bladder syndrome (PBS).



2. Perform more intensive evaluation on a sample of symptomatic subjects and on control subjects.



3. Draw a sample for intensive study from a region in the United States with proximity to one or more clinical evaluation sites.




4. Consider a national strategy for telephone surveys if cost permits.



5. Include persons with early symptoms of the illness in the study. For example, rather than restricting enrollment to persons whose symptoms have existed for six to nine months—as was done in previous IC trials—include subjects whose symptoms have persisted for four weeks or more and who do not have a bacterial infection. Enrollment targets should insure an adequate number of short-term patients.



6. Limit the survey to persons with bladder symptoms rather than persons who have vulvodynia or chronic pelvic pain.



7. Perform prospective studies to identify the risk factors for development of IC/PBS.



8. Perform a longitudinal study of symptomatic subjects and controls as resources permit. Although the case literature and the Interstitial Cystitis Data Base provide some valuable information on the natural history of established IC, the natural history of early symptoms is unclear.



9. Perform studies to validate the sensitivity and specificity of antiproliferative factor for diagnosis of interstitial cystitis. Assess the value of measuring antiproliferative factor in a sub-group of symptomatic persons to predict progression of IC and to monitor their responses to therapy.



10. Collect biosamples from subjects and perform microarray and proteomics analyses to develop other markers of IC that might contribute to an understanding of disease pathogenesis. Samples suitable for such studies should be stored in a repository, and access should be arranged for qualified investigators.

E. Darracott Vaughan, M.D. (Co-Chair)
James J. Colt Professor of Urology
Department of Urology
Cornell University Medical College
525 E-68th Street
Room Starr 900, Box 94
New York, NY 10021
Phone: 212-746-5480
Fax: 212-746-8344
evaughan@med.cornell.edu

Timothy Wilt, M.D.(Co-Chair)
Professor of Medicine
C/O VA Medical Center
General Internal Medicine 1110
1 Veterans Drive
Minneapolis, MN 55417
Phone: 612-725-2158
Fax: 612-725-2118
Wiltx001@umn.edu

Gary C. Curhan, M.D.
Associate Professor
Channing Laboratory
Brigham & Women’s Hospital
181 Longwood Avenue
Boston, MA 02115
Gary.curhan@channing.harvard.edu
Phone: 617-525-2683
Fax: 617-525-2008

Philip Hanno, M.D.
Hospital of University of Pennsylvania
Division of Urology
3400 Spruce Street
Philadelphia, PA 19104
Phone: 215-662-7722
Fax: 215-662-3955
phil.hanno@uphs.upenn.edu