The purpose of this study is to assess the effectiveness and costs associated with the intravesical administration of combined hyaluronic acid (HA) and chondroitin sulphate (CS) compared to the current standard management of recurrent urinary tract infections in adult women diagnosed with recurrent urinary tract infections (RUTI).

RUTI is defined as at least three episodes of uncomplicated urinary tract infections accompanied by clinical symptoms and documented by urine culture with the isolation of >103 colony forming units (CFU)/ml of an identified pathogen in the last year (M. Grabe, T.E. Bjerklund-Johansen, H. Botto, B. Wullt, M. Çek, K.G. Naber, R.S. Pickard, P. Tenke, F. Wagenlehner. Guidelines on Urological Infections. European Association of Urology 2012).

In order to do so, we will perform a retrospective analysis on prospectively collected patient data in nine European centres.

The treatment schedule for the intravesical administration of combined hyaluronic acid (HA) 1.6% and chondroitin sulphate (CS) 2.0% is one instillation per week for the first month, followed by one instillation every two weeks for the second month and one instillation per month until stable remission of the symptoms.

The current standard management of RUTI in Europe is represented by the antimicrobial prophylaxis (continuous or postcoital), as described in the Guidelines on Urological Infections of the European Association of Urology or Immunoactive prophylaxis or Prophylaxis with probiotics or Prophylaxis with cranberry, or combination of these.

We will collect patient characteristics as age, BMI, sexual activity, employment status, severity of the disease, comorbidities.

Our primary clinical outcome will be the occurrence of objective (bacteriologically confirmed) recurrence within 12 months after the start of the treatment. Other outcomes will be the occurrence of clinical or symptoms based recurrence; the time to objective or symptoms based recurrence, evaluated from the start of the treatment until the first occurrence of an objective or symptoms based urinary tract infection, and the overall number of objective or symptoms based urinary tract infections experienced within 12 months after treatment initiation for RUTI.

Information about health related quality of life at baseline and 12 months will be recorded if available.

In terms of resource utilization, we will record the number of medical visits, number and types of laboratory, imaging and instrumental exams, hospitalization, consumption of pharmaceuticals or instrumental therapies (other than intervention and comparator) used within 12 months since treatment initiation. Number of days absent from work due to RUTI will be recorded when available. Costs will be attributed according to the perspective of the National Healthcare System searching for relevant data sources in each country.

Standard descriptive statistics, such as mean, median, range, and proportions, will be used to summarize patient characteristics and other collected variables. The Chi-Square test will be used to compare differences in proportions and the Mann-Whitney U test to compare continuous variables, with or without logarithmic transformation. The Kaplan-Meier method will be used to estimate time to recurrence outcomes.

Inclusion Criteria:

• Women aged 18-75 years old.
• Women diagnosed with recurrent urinary tract infections, defined as at least three episodes of uncomplicated urinary tract infections accompanied by clinical symptoms and documented by urine culture with the isolation of >103 CFU/ml of an identified pathogen in the last year. Uncomplicated or 'simple' UTI is defined as an infection in a person with normal urinary tract and function.

Exclusion criteria:

- Women with complicated urinary tract infections. Complicated urinary tract infection occurs in individuals with functional or structural abnormalities of the genitourinary tract.

The study will consider women with recurrent urinary tract infections who started their treatments at the Urology Departments at the enrolling centres.