A prospective study of interstitial cystitis: results of longitudinal followup of the interstitial cystitis data base cohort. The Interstitial Cystitis Data Base Study Group.

Purpose: We present baseline characteristics and longitudinal profiles of symptoms in the Interstitial Cystitis Data Base study, a prospective cohort study of patients with interstitial cystitis.
Materials and Methods: A total of 637 eligible patients were entered into the study and followed for symptoms of pain, urgency and urinary frequency. Median followup was 31 months.
Results: More than 90% of patients were white women with a median age of 43 years. Using the overall pain-urgency-frequency score 7% of participants presented with mild, 44% with moderate and 49% with severe symptoms. Severe urgency in 41% of cases and severe 24-hour frequency in 41% were more common than severe pain in 29%. Of the patients 51% reported nighttime frequency of 2 or more voids. Median duration of interstitial cystitis symptoms was 8 years and 68% of participants were previously diagnosed with the condition. The 36% of patients who withdrew from study or were lost to followup were more likely to have had more severe symptoms at baseline. Patterns of change with time suggest initial symptom improvement due to regression to the mean, and an intervention effect associated with the increased followup and care of cohort participants. Although all symptoms fluctuated, there was no evidence of significant long-term change in overall disease severity.
Conclusions: Our observations support the clinical observation that interstitial cystitis is a chronic disease and no current treatments have a significant impact on symptoms with time. These results provide a foundation for the design and performance of future clinical trials in interstitial cystitis using these end points in a similar patient population.