Interstitial cystitis (IC) is a chronic pelvic condition in the absence of other pathology leading to significant morbidity with limited available treatment options. Cystoscopic hydrodistension (HD) remains an offered intervention for diagnosis and management, providing temporary relief in some patients. There is no overall consensus regarding the optimal duration of HD. This systematic review aims to comprehensively assess the existing literature to identify if there is a relationship between HD time and treatment efficacy.

A systematic search in MEDLINE, Embase, and PubMed between January 1969 to April 2024 was performed to identify relevant articles investigating the efficacy of HD as a sole treatment for IC. Two independent reviewers screened abstracts and full texts, and a third resolved conflicts. Quality assessment was performed by two independent blinded authors using The Risk Of Bias In Non-randomized Studies – of Interventions (ROBINS-I) assessment tool. Data regarding population characteristics, duration of HD, treatment number and method, outcome measurements and values were extracted. Included articles were subcategorised into standard (<15mins) and prolonged (>15mins) HD durations.

A total of 1327 patients in 14 studies were included. Ten studies were prospective or retrospective cohort studies, and four were randomised controlled trials. Nine trials investigated the effect of HD for 15 minutes or less. Of these, four demonstrated no statistically significant differences in pre-operative and post operative symptoms and voiding function between 1 month and 6 months. Four trials found significant improvement in subjective patient symptom scores. Of these, one study investigated two groups of different HD times via different surgeons, and found significant improvements in pain scores for patients in those undergoing HD for 2 minutes (Pre: 2.4 vs Post: 5.5) and over 5 minutes (Pre: 1.3 vs Post: 3.6). A final study found a time to therapeutic failure post 3 minute HD of 25.2 months. Five trials performed prolonged HD between 30 minutes to 2 hours in a total of 152 patients. All were older studies (1977-2003) and performed HD under spinal or local anaesthetic. These studies demonstrated long term symptomatic improvement in included participants (32.3 - 67.3%) with follow up durations of 7 months to 3.2 years. Overall risk of bias across domains was assessed as high between included studies.

HD remains a contentious treatment option for IC, with limited long-term results in the literature. Our study suggests longer HD times may result in improved efficacy and duration of symptom relief. However, risk of bias, observational study designs, heterogeneity, and lack direct comparisons in durations of HD limits our conclusions. This review underscores the need for larger, prospective trials in determining the effects of HD duration on treatment efficacy.