Patients
Data retrospectively derived from 151 patients that underwent therapy for the treatment of rUTIs at Diaconessen Hospital Leiden (The Netherlands) were analyzed. Patients were chronologically selected from the hospital’s database based on start of treatment and the selection process was stopped, as soon as 50 patients per group were identified that met all in- and none of the exclusion criteria. 50 patients had been treated with 0.2% CS (CS), 50 patients with a combination of CS and low-dose long-term antibiotics (LDLTABCS), and 51 patients had received low-dose long-term antibiotics (LDLTAB). According to EAU guidelines [28], inclusion criteria focused on patients that experienced at least 3 episodes of uncomplicated cystitis in the last 12 months prior to the start of treatment, or 2 episodes in the last 6 months prior to the start of treatment as well as a positive culture of uropathogens at ≥ 103 CFU/ml. Data from patients younger than 18 years, pregnant patients, patients with a positive urine culture of uropathogens ≤ 103 CFU/ml, patients with urogenital defects/abnormalities, or a post voiding residual volume of > 50 ml were excluded from this retrospective data analysis. Medical histories of the patients were documented prior to the start of treatment with CS and/or LDLTAB. Data recorded for baseline, after 6 months, and 12 months of treatment were evaluated for efficacy and safety of treatment.
Study design and treatment regime
Within hospital’s routine patients were asked, whether they would agree to evaluation and publication of data obtained during their treatment for research purpose and gave informed consent electronically. This retrospective analysis has been approved by the Ethics Committee at Diaconessen Hospital Leiden, in accordance with the provisions of the Declaration of Helsinki. Data of patients were not included within this analysis, if the in- and exclusion criteria were not met.
Prior to the start of treatment, the medical history of the past 12 month was documented. Additionally, the parameters defined were documented prior to start of the treatment, after 6 months, and after 12 months of treatment.
Patients received either CS and/or LDLTAB. According to the instructions for use and the treatment regime established at Diaconessen Hospital Leiden, patients receiving CS or LDLTABCS were treated with 40 ml of 0.2% CS solution (Gepan® instill) per instillation. The treatment was applied by a trained nurse under the supervision of the attending urologist, or by the urologist (see Additional file 1 for further details on the protocol for instillation). Following the first instillation, patients underwent the following protocol: weekly instillations for a duration of 6 weeks, followed by instillations every 2 weeks for 2 months, which were followed by instillations every 3 weeks for approximately 2 months, with subsequent instillations every 6 weeks up to a total duration of 1 year. For treatment with LDLTAB alone or in combination with CS patients received one of the following antibiotics decided by the physician in charge based on the treatment regimens valid at the hospital in accordance with respective treatment guidelines and based on the patient’s individual characteristics and anamnesis on the individual antibiotic treatment: Furadantine® (Nitrofurantoin, 50 mg, 1 × day, 6 months), Noroxin® (Norfloxacin, 400 mg, 2 × day, 3 months), Augmentin® (Amoxicillin/clavulanic acid, 625 mg, 1 × day, 3 months), Monotrim® (Trimethoprim, 100 mg, 1 × day, 6 months) or Ciproxin® (Ciprofloxacin, 500 mg 1 × day, 3 months). Prior to the start of treatment, after 6 months of treatment, and after 12 months of treatment, patients filled in a standardized quality of life questionnaire (EQ-5D) according to the hospitals’s treatment routine.
Study parameters
Patient number, date of birth, gender and body mass index were noted to demographically describe the patients. The following documented parameters have been collected and evaluated: date of visits/start of treatment, confirmed dates of infections, positive urine culture for uropathogens (≥ 103 CFU/ml), identification of uropathogens, antibiotic sensitivity, prescribed antibiotic treatment, cystoscopy, QoL (EQ-5D), visits to the specialist.
Data management and evaluation
Pseudonymized data were obtained from Diaconessen Hospital Leiden. Patient identities were substituted by an identification code that was recorded on any form submitted to the sponsor of this data evaluation.
Data entry, check for quality and plausibility (double-checked each) and evaluation took place from March to July 2015. The following descriptive statistics were calculated: N (number of non-missing observations), mean (arithmetic mean), standard deviation (SD), standard error of the mean (SEM). For categorical data (nominal and ordinal variables) absolute and relative frequencies were calculated. Exploratory comparisons between groups and within groups were performed by using one-tailed and paired or unpaired t-tests.
The determination of the sample size was not based on biometric considerations. However, the sample size was considered to be sufficient to meet the objectives of this retrospective study.