The full study protocol was approved by the Research Ethics Committee from Yueyang Hospital of integrated traditional Chinese and Western Medicine. Informed consent was obtained from all patients involved in the study with no amendments (No. 2016LCSY030).
Cross-cultural adaptation and translation
Stage I: translation the IPSS, and BII into simplified Chinese language and synthesis
The forward translation was conducted by two native bilingual Chinese-speaking translators independently (T1 and T2), one was a urologist, and the other was a professional English translator, then the two translated versions (T1 and T2) were compared for any inconsistencies, and synthesized into T1-2. It was then back-translated into English by two independent native English-speaking professional translators (B1 and B2), who did not know the original English IPSS, and BII in advance. The translated versions (T1, T2, T1-2, B1 and B2) were compared with the original English version by all the translators and a bilingual expert committee, consisting of a senior English teacher, an urologist, and a cross-cultural translation expert. A pre-final simplified Chinese IPSS and BII was established by consensus from all the translators and the expert committee.
After all, 31 BPH patients with LUST who met the following inclusion criteria: (1) native simplified Chinese speakers; (2) men who were 45 years old or older, with LUTS due to BPH; and (3) had no reading difficulty in Chinese, were enrolled to complete the pre-final simplified Chinese IPSS, and BII. The patients finished the questionnaire, and they were asked if the items were clear and easy to understand. Suggestions and doubts were also collected from these patients. All the translators, and the expert committee discussed, and revised the pre-final simplified Chinese IPSS and BII according to these details as the final version.
Stage II: test of the final version
A booklet, covering the final simplified Chinese IPSS, BII, as well as the visual prostate symptom score (VPSS), 36 items Short Form Health Survey (SF-36), and Patients’ Global Evaluation (PGE) was used in the study. Meanwhile, participant demographic information was also included, including age, disease duration, and so on.
The study involved native simplified Chinese-speaking men at least 45 years of age, with LUTS due to BPH who consecutively consulted in Yueyang Hospital of integrated traditional Chinese and Western Medicine, Shanghai Seventh People’s Hospital, and Longhua Hospital, Shanghai University of Traditional Chinese Medicine.
The sample size of such a cross-cultural adaptation should meet two conditions; the sample size should be above 100, and over 7 times the number of items. The IPSS has eight items, and BII had 10 items, therefore, at least 100 patients needed to be enrolled .
International prostate symptom score
IPSS evaluated a combination of voiding symptoms (IPSS-symptom) and QoL related to voiding (IPSS-QoL). The IPSS-symptom allows the patient to choose 1 of 6 answers indicating increasing severity of the particular symptom. The answers are assigned points from 0 to 5. The total score of IPSS-symptom ranges from 0 to 35, higher scores indicating greater BPH symptom-related impact . The IPSS-QoL is a six-point Likert scale, higher score indicating lower QoL impacted by BPH symptom.
Benign prostatic hyperplasia impact index
The BII measures physical discomfort, worry, bother, and interference with usual activities, then the physical discomfort, worry, and bother items have a four-point Likert scale; and the interference with usual activities item has a five-point Likert scale. The total score ranges from 0 to 13, higher scores indicating greater BPH symptom-related impact .
Visual Prostate Symptom Score
VPSS is an alternative questionnaire used to avoid the aforementioned problems when using the IPSS. It can be used to assess urinary frequency during daytime and nighttime, the stream of urine, and the QoL by means of pictograms .
The Short Form Health Survey (SF-36)
The SF-36 is used to evaluate patients’ QoL with eight dimensions, ranging from 0 (poor health) to 100 (good health) . It was suggested that the simplified Chinese version of the SF-36 functioned in the general population of China quite similarly to the original American population tested .
Patients’ Global Evaluation
A 7-point Likert scale ranging from “completely recovered”, “much improved”, “slightly improved”, “slightly worsened”, “much worsened” to “worse than ever” was used to evaluate participants’ overall status .
Data were tabulated using Microsoft EXCEL, and rigorous statistical analyses were performed using IBM SPSS Statistics Version 21.0 (IBM Corp., Armonk, NY).
Exploratory factor analysis was performed by the principal-component analysis . Cronbach’ α was used to assess the internal consistency of the scales. Generally, a Cronbach’ α >0.7 is regarded as acceptable. All the completed baseline data of the Chinese IPSS and BII were included in the analysis .
The intraclass correlation coefficients (ICCs) were used to evaluate the test-retest reliability of Chinese IPSS and BII. An ICC above 0.7 is considered to show good reliability. As the patients did not wish to stop their treatment, only the patients reported “no changed” on the patients’ global evaluation were enrolled in the test-retest reliability evaluation.
In the absence of a gold standard for BPH, criterion validity could not be evaluated. To assess criterion-related validity, we examined construct validity. We evaluated the relationships between the Chinese IPSS, BII, as well as VPSS, and SF-36 using the Pearson correlation coefficients (r), where r > 0.40 was considered satisfactory (r > 0.80 is considered excellent, 0.61-0.80 very good, 0.41-0.60 good, 0.21-0.40 fair, and 0-0.20 poor). All the completed baseline simplified Chinese IPSS, BII questionnaires with VPSS, as well as SF-36 scores were included in the analysis.
Floor and Ceiling Effects
Distributions of the items in simplified Chinese IPSS, and BII were checked for floor and ceiling effects, and more than 15% of respondents achieve the lowest or highest possible total score were considered with floor and ceiling effects. All the completed baseline simplified Chinese IPSS, and BII questionnaires were included in the analysis.