Overactive bladder (OAB) is defined as "urgency, with or without urge incontinence, usually with frequency and nocturia" whereas mixed urinary incontinence (MUI) is the involuntary loss of urine during exertion, sneezing, or coughing, as well as leakage associated with urgency. Questionnaires like the Overactive Bladder Symptom Score (OABSS) can be used in objective diagnosis  of those conditions. The Blaivas OABSS is self-administered questionnaire consisting of 7 questions on a 5-point Likert scale. The questions relate to all symptoms of OAB, including one each for urinary frequency and nocturia, 3 for urgency, 1 for urge incontinence and 1 generic question concerning bladder control. The total score range is 0-28. The higher the score, the worse are the symptoms. The objective of this study was to validate the effectiveness of the 7 question- OABSS for Polish use by ascertaining the validity, test-retest reliability and internal consistency of a professional translation in order to provide a useful diagnostic tool for  women who are suffering from urinary incontinence (UI) and to correlate it with urodynamic study and UDI-6, IIQ-7 questionnaires. For both UDI-6 and IIQ-7, higher score = higher disability – (completely compromised by urinary symptoms = 100)

The inclusion criteria selected out a total of 824 women with UI, aged between 18-75 years. Patients were recruited from women attending the Outpatient Clinic between June 2017 and December 2018. From these individuals, socio-demographic data (including age, gravidity, parity, BMI and menstrual status) were collected.  All individuals within the study population spoke Polish as their native language. Of the experimental group, recruitment medical examination/case history showed that SUI was observed in 290 cases; OAB in 285 patients and 249 had MUI (confirmed by medical history and urodynamic investigation performed during visit week 0). All patients completed the OABSS questionnaire at baseline (visit week 0). Moreover, 821 women repeated the OABSS and 824 completed the UDI-6 and IIQ-7 self-assessment again after 14 days. 23 patients who did not reappear on visit week 2 were excluded from evaluation. No patient received treatment during that time. In this part of the study, only the answers of patients who fully completed the questionnaires were taken into account. The internal consistency of the 7 questions in OABSS was tested by calculating Cronbach's alpha by way of  employing baseline scores. The high reliability of the scale indicates a value greater than 0.7. The reliability was calculated with the Intraclass Correlation (ICC), and was considered acceptable when ICC was ≥0.7. 
Statistical analysis was performed using  Statistica v. 12.0 software (StatSoft, Poland).P values less than 0.05 were considered significant. Significance of  differences of means between studied groups  was assessed  using one-way ANOVA and the Tukey post hoc test.
All patients gave informed consent to participate in the study and to complete the questionnaires.

Demographic parameters of the patients are given in Table 1
Mean scores +/-SD of patients responses are shown in Table 2. 
The Cronbach's alpha values for the OABSS  questionnaire in the SUI group was 0.89, OAB-0.9 and MUI-0.82.
In all study groups, ICC was >0.99. 
Table 2 shows mean+/-SD  UDI-6 and IIQ-7 Questionnaire scores among patients from study groups.

There was statistically significant difference (p<0.0005) between mean  scores among patients from study groups (OAB-SUI and MUI-SUI) measured by OABSS questionnaire. There was no statistically significant difference between patients from MUI and OAB group (p<0.11). Analysis did not show statistical significance between visits.
UDI-6 and IIQ-7 results show statistically significant difference among patients from all study groups- OAB, SUI and MUI.

The OABSS is condition-specific quality of life instruments that is easy to distribute and understand. Our study shows that it is reliable, widely used  but, unfortunately, until our study, has never been used in Poland or translated into Polish. Moreover, in none of the publications where OABSS was used, authors assessed patients from MUI group. Our study show similar answers between patients from OAB and MUI group (p>0.05) so OABSS cannot distinguish this two groups Given the presented data, the use of the Polish version of OABSS is adequate for the Polish population of patients but it cannot distinguish OAB and MUI type of UI. We think that adding UDI-6 and IIQ-7 to the OABSS will not help in distinguishing between OAB and MUI because as previously confirmed UDI-6 is not the best test in MUI diagnosis and IIQ-7 assess the psychosocial impact of urinary incontinence in women.