Phenotypic differentiation of patients with interstitial cystitis/bladder pain syndrome (IC/BPS) may improve our understanding of the condition, as well as the development of patient-specific treatment strategies. We identified a distinct subgroup of IC/BPS patients with a multiple sensitivity phenotype.
We defined patients with this IC/BPS associated multiple sensitivity syndrome as having at least 3 confirmed allergies/sensitivities to medications and/or environmental factors and a diagnosis of IC/BPS. These IC/BPS patients identified with a multiple sensitivity phenotype (cases) were compared to age-matched IC/BPS patients with few or no allergies (controls) at a 1:2 ratio. Comparisons were undertaken using standardized case assessment parameters (age, duration of symptoms, medical history, Interstitial Cystitis Symptoms Index [ICSI] and pelvic pain and urinary urgency/frequency [PUF] symptom scores, and urinary, psychosocial, organ specific, infection, neurologic/systemic, tenderness [UPOINT] categorization).
The study consisted of 17 cases and 34 age-matched controls; the mean age was 55 and 56 years, respectively. There was statistically more medication and environmental allergies in the cases versus controls. Cases reported more concomitant illnesses (9.6 vs. 6.2, p < 0.001) and number of bodily systems affected (6.0 vs. 3.8, p ≤ 0.001). The prevalence of irritable bowel syndrome and fibromyalgia was higher in the case group (p = 0.028, p ≤ 0.001, respectively). Additionally, there were more reported psychiatric diseases (p = 0.019), allergic/immune diseases (p = 0.003), and pulmonary diseases (p < 0.001) in the case group. UPOINT classification differed with more patients in the case group being categorized in the psychosocial and neuropathic/systemic domains (p = 0.045, p = 0.007, respectively). Total UPOINT classification (out of 6) was also higher in cases than controls (4.6 vs. 3.2, p = 0.001, respectively).
We have characterized a distinct phenotypic group of patients with IC/BPS and multiple sensitivities. The limitations of our study include the retrospective case-control matching design, biases in phenotype definition, single centre patient recruitment, and the lack of follow-up. Nonetheless, the observation of this specific phenotype suggests that further research in this group may help develop targeted therapeutic strategies for patients with a concomitant multiple sensitivity syndrome and IC/BPS.