Design and study sample
A cross-sectional study design was used. Women with SUI were recruited from the obstetrics and gynecology outpatient department and urodynamics examination room of a hospital through convenience sampling from August 2021 to March 2022. During the study period, potential participants were referred by an obstetrician. In addition, flyers used to advertise the study were placed in the outpatient department to recruit participants from the hospital. Women who were willing to participate in the study could contact the investigator. The investigator ensured that women met the inclusion criteria by interviewing them and checking their medical records. The research methodology, content, and study purpose were explained to eligible women. After obtaining verbal and written consent, a structured questionnaire was given to participants. The inclusion criteria were as follows: women with SUI confirmed by a physician; over 20 years old; and agreed to participate in the study and sign a consent form. Exclusion criteria were as follows: women with a Barthel Index score below 90; those who had urinary catheters; those who were unable to communicate; those with urinary incontinence due to cancer or severe illness; and those with psychiatric disorders, such as major depression and dementia.
Estimated sample size
A correlation coefficient (r) of 0.70 between the score on the Geriatric Self-efficacy Index for Urinary Incontinence (GSE-UI) and the score on the Incontinence QOL questionnaire previously reported in patients in an incontinence study was used as the basis for sample size estimation [16]. The sample size was estimated using G*Power Version 3.1.9.2 [21] with the following parameters: for linear regression statistical analysis, α = 0.05, power = 80%, and independent variables = 14. This resulted in a required sample size of at least 33 participants. Of 174 potential participants, 32 did not meet the inclusion criteria, and seven declined to participate due to the time commitment required. A total of 135 participants completed the questionnaire.
Measurements
Sociodemographic and health information list
The data collected on this scale consisted of basic demographic properties and disease treatment characteristics. The items included age, education level, religious beliefs, marital status, occupation, self-reported financial status, chronic disease, self-reported health status, menopausal status (e.g., perimenopausal, post-menopausal), and SUI treatment. In addition, we recorded the numbers of newly diagnosed COVID-19 cases reported by the Central Epidemic Command Center in Taiwan [22] on the dates when participants completed the questionnaire.
Distress caused by symptoms of urinary incontinence
A short version of the Urogenital Distress Inventory (UDI) included a total of six questions, which were part of the three subscales of obstruction, stress, and irritation. A 4-point scoring method was adopted, with a score range of 0–3, and the score was linearly scaled to 0–100. A higher score indicates greater distress [23, 24]. The scale has acceptable reliability and validity [23]. A UDI-6 score of 33.33 has a specificity of 83.3% and a sensitivity of 97.0% for detecting greater distress caused by urinary incontinence [25]. The Chinese version scale has acceptable criterion, convergent, and discriminant validity [6, 26] as well as acceptable reliability, with a Cronbach’s α of 0.80 [26]. The Cronbach’s α in this study was 0.75.
Self-efficacy index for urinary incontinence
A total of 12 questions in the GSE-UI were administered, using a 10-point scoring method. The total score ranged from 0 to 120. A higher score indicates better self-efficacy for urinary incontinence [16, 27]. This original English scale has a specificity of 78.2% and a sensitivity of 75.1% for detecting clinically significant changes in patients with urinary incontinence. The Cronbach’s α of the internal consistency of the scale was 0.90 [27]. With the consent of the original scale developers, this study used the forward-backward method to translate the English version scale into a traditional Chinese version scale [28]. Then, expert validity and face validity were verified, and the contents of the scale were adjusted according to expert opinion to construct a scale that could be used with women with SUI in Taiwan. The content validity index was 1.0 [29], and the Cronbach’s α was 0.92.
Positive thinking
The Positive Thinking Scale comprises personal satisfaction and goal pursuit. The scale includes a total of 18 questions and uses a 5-point scoring method. The total score ranges from 18 to 90. A higher score indicates a greater perception of positive thinking [18, 30, 31]. The Korean version of the original scale has acceptable discriminant and convergence validity. The Cronbach’s α of the total scale internal consistency was 0.88 [18, 19]. The Chinese version scale has acceptable concurrent, predictive, and construct validity, and the Cronbach’s α of the internal consistency ranged from 0.88 to 0.98 [30, 31]. In this study, the Cronbach’s α was 0.93.
General quality of life
The Chinese version of the 12-Item Short-Form Health Survey (SF-12) was used to assess general QOL in the study participants. The SF-12 is a short version of the SF-36, easy to complete, and less burdensome [32]. The SF-12 consists of eight domains, namely, general health, physical functioning, bodily pain, vitality, role physical, role emotional, social functioning, and mental health. The scores are converted into a physical component summary (PCS) score and mental component summary (MCS) score by using PRO CoRE software. A higher score reflects better physical and mental QOL. The SF-12 can explain more than 90% of the score variation of the SF-36 with acceptable reliability [33, 34]. The Chinese version of the SF-12 has acceptable reliability and validity [32].
Urinary incontinence-specific quality of life
The Chinese version of the Incontinence Impact Questionnaire short form (IIQ-7) has been used widely to assess urinary incontinence-specific QOL [26]. This study used the IIQ-7 to assess urinary incontinence-specific QOL in women with SUI. The scale contains seven questions that cover four subscales, namely, travel, physical activity, emotional health, and social/relationships. Using a 4-point scoring method, the score was linearly scaled to 0–100. A higher score indicates a greater impact caused by urinary incontinence and worse urinary incontinence-specific QOL [24, 26]. The Chinese version of IIQ-7 has criterion, convergent, and discriminant validity. The Cronbach’s α of the total scale reliability was 0.93 [26]. The Cronbach’s α in this study was 0.89.
Ethical considerations
This study was approved by the Institutional Review Board of the hospital (No. 20210107R) and was performed in accordance with the Declaration of Helsinki. The researchers explained the content and purpose of the study to women who met the inclusion criteria and gave them time to reflect on their willingness to participate in the study. Questionnaires were completed only after women had agreed and signed the research consent form. Participants were allowed to discontinue or withdraw from this study at any time without prejudice to their therapeutic rights. The questionnaire information was coded in lieu of participant names and was locked in a steel cabinet in the investigator’s office to protect the data and ensure subject privacy.
Statistical analysis
Statistical analysis was performed using IBM SPSS Statistics version 20.0. Descriptive statistical methods included mean, standard deviation (SD), frequency, percentage, percentile, and range. Inferential statistics consisted of independent sample t-tests, one-way analysis of variance, Pearson product-difference correlations, and multiple linear regressions. When using stepwise regression for multivariate analysis, the variants were included in the analysis along with the statistically significant variables of univariate analysis, which included urinary incontinence symptom distress, urinary incontinence self-efficacy, and positive thinking. A two-tailed test was used, and a p-value of less than 0.05 indicated statistical significance.
