Treatment of ulcerative compared to non-ulcerative interstitial cystitis with hyperbaric oxygen: a pilot study.

BACKGROUND: The etiology of interstitial cystitis (IC) is often idiopathic but can be due to Hunner's ulcers. Hyperbaric oxygen (HBO) is used to treat ulcerative disease of the superficial skin. We hypothesized that HBO can treat ulcerative IC (UIC) but would be less efficacious for non-ulcerative IC (NIC).

METHODS: Patients with NIC and UIC enrolled in this study. Following informed consent, demographic information was collected. A visual analog pain scale and validated questionnaires were collected; each patient underwent cystoscopy prior to treatment. Each subject met with a hyperbaric specialist and after clearance underwent 30 treatments over 6 weeks. Adverse events were monitored. Patients repeated questionnaires, visual analog pain scale and global response assessment (GRA) immediately, 2 weeks, 3, 6 and 12 months after treatment. Patients also underwent cystoscopy 6 months after treatment. Differences before and after treatment were compared.

RESULTS: Nine patients were recruited to this study. One was unable to participate, leaving two subjects with NIC and six with UIC. All patients completed HBO without adverse events. Three patients completed HBO but pursued other therapies 7, 8.5 and 11 months after treatment. On GRA, 83% of patients with UIC were improved. This treatment effect persisted, as 66% of UIC patients remained better at 6 months. In contrast, only one patient in the NIC group improved. Questionnaire scores improved in both groups. Pain scores improved by 2 points in the UIC group but worsened by 1.5 points in the NIC group. Two patients with ulcers resolved at 6-month cystoscopy.

CONCLUSION: HBO appeared beneficial for both UIC and NIC. Data shows slightly better benefit in patients with UIC compared to NIC; both groups showed improvement. Given the small sample size, it is difficult to draw definitive conclusions from these data. Larger studies with randomization would be beneficial to show treatment effect.