BERKELEY, CA (UroToday Inc.) - Interstitial cystitis (IC) is an enigmatic disease. The true prevalence of the disease is not known. As interest in studying IC has increased, new validated instruments have been created which may better estimate the true number of people with IC. Drs. Parsons and Tatsis from the University of California San Diego Medical Center in San Diego, California have suggested that up to 22% of women from the general population may have IC. This judgment was based on the use of the validated Pelvic Pain and Urgency/Frequency Patient Symptom (PUF) scale that they developed. This questionnaire screens for frequency, urgency, pelvic pain, and sexually associated flare of symptoms.

They subsequently hypothesize that the use of the PUF scale and potassium sensitivity test (PST) for IC screening in a random sample of the female general population will lead to discovery of a comparable prevalence. Their results were published in the November 2004 edition of Urology.

They studied all females in the third-year medical student class at the University of California San Diego by asking them to complete the PUF scale. 94% (49/52) completed the questionnaire. The median age was 26. 41% (20/49) had a score of less than 2, which was considered evidence that IC symptoms are not present, while 31% (15/49) scored 7 or greater, which could indicate the presence of IC These latter persons were asked to undergo further clinical evaluation including a urinalysis, urine culture, and PST. All were sexually active. Five of the 15 women scoring higher than 7 consented to have PST, and all tested positive. These women met the NIDDK criteria for IC, excluding urodynamics and cystoscopy. Therefore, overall 5/52 (10%) of the women had documented IC.

The authors conclude that using the PUF scale as a screening instrument, even in this small group of medical students, reveals that 31% of women probably have IC and that a minimum of 10% has documented IC. Therefore, the worldwide IC prevalence is likely to be higher than previously estimated and may affect upwards of 25 to 30 million women. They suggest that screening with the PUF scale may help to identify women with undiagnosed IC.

Urology 2004;64:866-870