Comparison of an interstitial cystitis/bladder pain syndrome clinical cohort with symptomatic community women from the RAND Interstitial Cystitis Epidemiology study

The RAND Interstitial Cystitis Epidemiology survey estimated that 2.7% to 6.5% of United States women have urinary symptoms consistent with a diagnosis of interstitial cystitis/bladder pain syndrome. We describe the demographic and clinical characteristics of the symptomatic community based RAND Interstitial Cystitis Epidemiology cohort, and compare them with those of a clinically based interstitial cystitis/bladder pain syndrome cohort.

Subjects included 3,397 community women who met the criteria for the RAND Interstitial Cystitis Epidemiology high sensitivity case definition, and 277 women with an interstitial cystitis/bladder pain syndrome diagnosis recruited from specialist practices across the United States (clinical cohort). Questions focused on demographic information, symptom severity, quality of life indicators, concomitant diagnoses and treatment.

Average symptom duration for both groups was approximately 14 years. Women in the clinical cohort reported worse baseline pain and maximum pain, although the absolute differences were small. Mean Interstitial Cystitis Symptom Index scores were approximately 11 for both groups, but mean Interstitial Cystitis Problem Index scores were 9.9 and 13.2 for the clinical cohort and the RAND Interstitial Cystitis Epidemiology cohort, respectively (p <0.001). The RAND Interstitial Cystitis Epidemiology subjects were more likely to be uninsured.

The RAND Interstitial Cystitis Epidemiology community cohort was remarkably similar to an interstitial cystitis/bladder pain syndrome clinical cohort with respect to demographics, symptoms and quality of life measures. In contrast to other chronic pain conditions for which clinical cohorts typically report worse symptoms and functional status than population based samples, our data suggest that many measures of symptom severity and functional impact are similar, and sometimes worse, in the RAND Interstitial Cystitis Epidemiology cohort. These findings suggest that interstitial cystitis/bladder pain syndrome is significantly burdensome, and likely to be underdiagnosed and undertreated in the United States.