A cross-sectional validation study was done to determine the structural validity and reliability of the Persian version of the PRAFAB questionnaire.

There were two phases. During the first phase, the translation process, the permission to translate PRAFAB into Persian was obtained from the developers. Forward Persian translation was done by two translators (a pelvic physiotherapist and a professional translator). The discrepancy between the two versions was solved through joint meetings and dialogs.

Another expert translator who is fluent in English translated the final Persian version into English. Expert panel consensus resolved discrepancies. Minor changes were made in the translated version. This group consisted of two urologists, three pelvic physiotherapists, two gynecologists, two English translators, and an epidemiologist.

The second phase concerned validity and reliability. The Persian version was studied for content validity, construct validity, internal consistency, and test–retest reliability.

The study was conducted in Al-Zahra hospital, Tabriz, Iran, from June to December 2021. Sixty women with UI participated in this study. All participating women filled out the final Persian version of the PRAFAB questionnaire, after the items were explained to them. They were asked to answer independently. For illiterate participants, an assistant filled out the questionnaire.

Women with involuntary leakage of urine, aged over 18, were included.

The patients with pregnancy, early postpartum, bladder cancer, diabetic nephropathy, previous central nervous system damage, congenital urological disorders, urinary tract infection, neurogenic bladder, severe cognitive impairment, and severe psychiatric illness were excluded [9,10,11,12]. The Ethics Committee of Tabriz University of Medical Sciences approved this validation study (code: IR.TBZMED.REC.1399.921).

The PRAFAB questionnaire includes five items graded on a Likert score from 1 to 4. The English and the Persian versions of the PRAFAB questionnaire are shown in Figs. 1 and 2.

The Protection, Amount, Frequency, Adjustment, Body image (PRAFAB) questionnaire score

The Persian version of Protection, Amount, Frequency, Adjustment, Body image questionnaire

The simplicity, comprehensibility, and accuracy of each item of the Persian version of PRAFAB was qualified by ten experts including urologists, gynecologists, and pelvic physiotherapists. The content validity was studied according to the content validity index (CVI) and the content validity ratio (CVR). The CVR was obtained by a three-point Likert scale including 1 (not necessary), 2 (useful but not necessary), and 3 (necessary). The CVI was determined by a four-point Likert scale for the simplicity, specificity, and clarity of each item.

Exploratory factor analysis (EFA) was conducted to measure the construct validity of the Persian version of PRAFAB. Based on the recommended sample size, there should be five to ten participants per measurement item [16]. According to the PRAFAB items, a minimum size of 25 to 50 subjects was required. Sixty women with UI symptoms were included to survey the EFA of the PRAFAB.

Internal consistency shows the complementary nature of items and is calculated using Cronbach’s alpha. To determine the PRAFAB’s internal consistency, a correlation between the questionnaire’s items was investigated (item to total).

A test–retest method was used to evaluate external reproducibility. Intra-class correlation coefficient (ICC) was used to analyze the data. The test–retest examination was performed on 20 women with UI. The interval between the two tests was 2 weeks. Participants did not change their lifestyles or receive any treatment during the test–retest period. All patients were visited after 2 weeks and received their treatment.

Descriptive statistics were used to calculate the central indicators and dispersion of demographic characteristics. The content validity of the Persian versions of PRAFAB was obtained by calculating the CVR and the CVI. Because of the number of experts participating in this study (n=10), CVR >0.591 and CVI values >0.79 were acceptable. Maximum likelihood with Promax rotation was used to examine the nature of the interrelationship of the PRAFAB measurements and the group-correlated measurements. Bartlett’s test of sphericity and the Kaiser–Meyer–Olkin (KMO) test were used to assess the appropriateness of the factor analysis model and the sampling adequacy respectively. Statistical analyses to test the reliability and the internal consistency of the questionnaire were assessed by Cronbach’s alpha coefficient (item to total). An instrument will have good reliability and be considered satisfactory when the alpha is equal to or greater than 0.70. Reproducibility was examined by the test–retest method, which suggested a time interval between two tests of 2 weeks to 1 month [3]. The ICCs were interpreted according to the Landis and Koch criteria (0–0.2 as poor, 0.21–0.4 as fair, 0.41–0.7 as moderate, 0.71–0.80 as substantial, and 0.81–1 as almost perfect) [16]. Alpha coefficients >0.7 were satisfactory for all domains.