ABSTRACT
Aim
This methodological study aimed to evaluate the validity and reliability of the Turkish version of the Stoma-Specific Quality of Life (SQOL-TR) questionnaire, developed to assess the Quality of Life in individuals with enteral and urinary ostomies.
Method
The study was conducted with 125 patients with ostomies at the stoma therapy unit of a university hospital in Ankara. Data were collected using a demographic information form, the Quality-of-Life Scale for Individuals with an Ostomy (O-QOL), and the SQOL-TR. In the first stage, linguistic validation and a pilot test were conducted. In the second stage, construct validity was assessed using confirmatory factor analysis, and concurrent validity was evaluated through comparison with the O-QOL. Reliability was tested via Cronbach’s alpha, composite reliability, and item analysis.
Results
Participants had a mean age of 59.66±12.70 years and an average ostomy duration of 16.47±21.86 months. Of these, 40.0% had colostomies, 29.6% ileostomies, and 26.4% urostomies. Psychometric analyses revealed a content validity index of 1.00. The questionnaire consisted of four subdimensions: elimination concerns, psychological impact, daily activities, and social relationships. It showed a strong positive correlation with the O-QOL (r=0.78, p<0.001) and a reliability coefficient of 0.964. All items demonstrated high discriminative power.
Conclusion
The SQOL-TR is a valid and reliable instrument for individuals with colostomies, ileostomies, or urostomies. Adapted into six cultures, it is suitable for use in multicenter and multinational research as well as clinical follow-up.
Introduction
Cancers of the colon, rectum, small intestine, and bladder are major contributors to global cancer-related morbidity and mortality.1, 2 According to data from the International Agency for Research on Cancer, colorectal cancer ranks as the fourth most frequently diagnosed malignancy worldwide, whereas bladder cancer ranks eleventh.3 Although cancers of the small intestine occur less frequently, they still represent a critical clinical concern. In Türkiye, according to 2019 data published in 2023 by the Ministry of Health, gastrointestinal cancers rank eighth among all malignancies.4 The standard treatment modalities for these cancers include surgery, radiotherapy, and chemotherapy. Depending on the tumor site and extent, surgical resection may lead to the formation of either a temporary or permanent ostomy.5, 6 In colorectal and small bowel cancers, anastomosis or ostomy formation is often required. In cases of muscle-invasive or high-risk non-muscle-invasive bladder carcinoma unresponsive to intravesical Bacillus Calmette-Guérin therapy, radical cystectomy followed by continent or incontinent urinary diversion is employed to ensure urinary excretion.7 An estimated 700,000 individuals in Europe live with an ostomy, including colostomy, ileostomy, and urostomy, with prevalences of 0.12%, 0.07%, and 0.02%, respectively.8, 9 In Italy, over 70,000 individuals live with an ostomy,10 whereas in the United States, this number reaches nearly one million.11 In Türkiye, Yılmaz et al.12 reported that 22,557 new ostomies were created nationally between 2017 and 2019.
Living with an ostomy can considerably impact a patient’s Quality of Life (QoL) across physical, psychological, and social dimensions.5, 13, 14 Patients frequently experience defecation or urinary control issues, odor, and skin irritation, along with psychological symptoms such as anxiety, depression, and social withdrawal.13, 14 These complications can lead to challenges in personal relationships, decreased intimacy, isolation, increased familial or social rejection, and even financial stress due to job loss or career changes.5, 13, 14 Although QoL assessment tools have evolved over the years,15, 16 many studies continue to rely on general QoL instruments that are not tailored to ostomy-specific concerns.7, 17, 18 A growing body of research has supported the use of ostomy-specific tools in recent years;15, 16 however, these often focus narrowly on selected QoL dimensions such as sexuality or social interactions.19, 20 Furthermore, most tools are validated only in individuals with enteral ostomies (colostomy, ileostomy)13, 16, 19, 21 or solely in urostomy populations.7, 17, 20 This highlights the need for an inclusive, culturally validated tool capable of evaluating QoL in individuals with both enteral and urinary ostomies. In Türkiye, the only existing adapted instrument is the Quality-of-Life Scale for Individuals with an Ostomy (O-QOL), developed by Karadağ et al. in 2011.22 Although the O-QOL has been accepted as a reliable measure, its scoring procedure is complex due to reverse-coded items and formula-based subscales. Furthermore, some items are irrelevant for patients without school or employment responsibilities, those without sexual partners, or individuals with urostomies.22
In response to these limitations, the Stoma-specific Quality of Life (SQOL) questionnaire was developed to comprehensively evaluate QoL in patients with ostomies. Unlike the O-QOL, it assesses sleep, sexual activity, family and social relationships, and broader psychosocial dimensions. Validated across multiple cultural contexts, including Italy, Spain, Brazil, Canada, and China, the SQOL has been shown to be appropriate for use in individuals with colostomy, ileostomy, and urostomy.8, 23-26 Although the original version did not include patients with urostomies, later studies emphasized the need to evaluate its reliability and validity in this group.27
Aim of the Study
There is a need for a culturally valid and reliable instrument tailored to the Turkish population to identify ostomy-related challenges, guide care practices, and assess the impact of clinical interventions aimed at improving QoL following ostomy surgery. Therefore, this study aims to examine the validity and reliability of the Turkish version of the SQOL (SQOL-TR) in individuals with enteral or urinary ostomies.
Research question: Is the SQOL questionnaire a valid and reliable tool for use among Turkish patients with ostomies?
Materials and Methods
Study Design and Sample
This methodological study followed standard cultural adaptation procedures and was conducted between February 2022 and February 2023 at the Stoma and Wound Care Unit of the Department of General Surgery, Hacettepe University Hospital. The study population included patients who had received ostomies at least 1 month prior and were being followed up in the same unit. In 2022, the unit monitored 132 patients with ostomies.
As stated by İlhan et al.28, in methodological research, sample size calculations should consider the ratio of the sample size to the number of scale items. Various scholars made the following suggestions: Everitt (1975) proposed a minimum ratio of 5:1, Cattell (1978) recommended at least 6:1, and Nunnally (1978) suggested a ratio of at least 10:1.28 Based on this data, the minimum sample size for the SQOL-TR, which consists of 20 items, was determined to be 100. The study was completed with 125 participants.
The inclusion criteria were as follows: voluntary participation, age 18 or older, having an ostomy for at least 1 month, literacy, and fluency in Turkish.
The exclusion criterion was as follows: any condition impairing communication (e.g., cognitive or neuropsychiatric disorders).
Data Collection Tools
Introductory Information Form
This form comprised 18 items designed to collect demographic information (e.g., age, gender, marital status, education level) and clinical characteristics related to the ostomy.
SQOL Questionnaire
Originally developed in English, the SQOL includes 20 items that evaluate the QoL in individuals living with an ostomy.27 Its Cronbach’s alpha (α) was reported as 0.92. The questionnaire targets four key domains: Sleep, Sexual Activity, Relations to Family and Close Friends, and Social Relations Outside Family and Close Friends. The original study confirmed a unidimensional structure for the questionnaire.
Although adaptations in Canada, Italy, Brazil, and Spain also recognized these four domains as sub-dimensions, no consensus was reached on item-to-domain mapping.23, 29-31 In contrast, Shao et al.32 restructured the Chinese version into four factors. Factor I, Social Relationship, merged items regarding both close and extended social relations. Factor II, Psychological Impact, included items addressing discomfort, embarrassment, concealment, body image, and sexual attractiveness, and the original Sexual Activity dimension was incorporated here. Factor III, Defecation Concerns, included items related to leakage, odor, and toilet access. Factor IV, Daily Function, reflected core tasks such as sleep and dressing, largely aligning with the original Sleep domain.32
Shao et al.32 reported Cronbach’s α coefficients of 0.93 for the total questionnaire and 0.73-0.83 for the sub-dimensions. The Turkish version adopted this factor structure:
Elimination concerns: Items 1-4
Psychological impact: Items 5, 9, and 11-14
Daily activities: Items 6-8 and 10
Social relationships: Items 15-20
Each item is rated on a 4-point Likert scale (1= always, 4= never). The total score ranges from 20 to 80, with higher scores indicating better QoL.
QoL Scale for O-QOL
To evaluate norm-referenced reliability, the O-QOL developed by Baxter et al.33 and validated in Turkish by Karadağ et al.22 was used. It contains 21 items and has an overall Cronbach’s α of 0.87. Subscales include Work/Social Life (6 items, α=0.77), Sexuality/Body Image (5 items, α=0.72), and Stoma Function (6 items, α=0.76). The first 2 items assess general satisfaction. The first part is scored 0-100, and the second part uses a 5-point Likert scale. The instrument also includes 2 single items addressing financial concerns and skin irritation. Subscale scores are calculated using specific formulas and range from 0 to 100, with higher scores reflecting greater QoL.22
Implementation of the Study
Linguistic Validation
To ensure linguistic validity, the original questionnaire was translated into Turkish by five bilingual experts with experience in ostomy care. These translations were synthesized into a single version and reviewed by another expert for accuracy. This Turkish version was then back-translated into English by a native-level speaker unfamiliar with the original questionnaire. The back-translation was compared with the original for semantic consistency, and necessary revisions were made. Finally, another bilingual expert evaluated both versions for conceptual equivalence, after which the final Turkish version was confirmed.
Content Validity
To evaluate the content validity of the linguistically adapted SQOL-TR, Davis’s34 technique was employed. In this method, each item in the questionnaire is assessed using a four-point structure: (a) appropriate, (b) needs revision, (c) needs major revision, and (d) not appropriate. The content validity index (CVI) for each item is calculated by dividing the number of experts selecting “a” or “b” by the total number of experts. A CVI greater than 0.80 indicates that the item is content-valid.34, 35 Accordingly, the evaluation form was reviewed by 10 doctoral-level experts in nursing with research experience in scale validation and ostomy care. Experts were also asked to provide suggestions regarding each item. Based on their feedback, items were scored on a 4-point scale: 4= very appropriate, 3= appropriate with minor revision, 2= requires modification, and 1= not appropriate. These evaluations were used to determine the appropriateness of each item.
Pilot Study of the Questionnaire
A pilot study was conducted with five participants to identify potential semantic or structural issues in the linguistically and content-validated the SQOL-TR. No modifications were required following the pilot phase. Participants involved in the pilot were excluded from the main data analysis.
Construct Validity
To assess the construct validity of the SQOL-TR, confirmatory factor analysis (CFA) was employed. The four-factor structure previously validated by Shao et al.32 was tested. Factor loadings and model-data fit indices were used to determine whether this model was validated. The fit indices included chi-square to degrees of freedom ratio (χ²/df), comparative fit index (CFI), non-normed fit index/Tucker-Lewis index (TLI), standardized root mean square residual (SRMR), and root mean square error of approximation (RMSEA).
Concurrent Validity
To assess concurrent validity, the SQOL-TR and the O-QOL were administered concurrently to 125 participants, and the correlation between the two instruments was calculated. Following the completion of validity analyses, reliability assessments were conducted.
Reliability Analyses
For the reliability assessment of the SQOL-TR, Cronbach’s α was calculated for the total questionnaire and all sub-dimensions. Additionally, the composite reliability coefficient was evaluated using McDonald’s omega, and item analysis was performed through a 27% sub-upper group comparison.
Statistical Analysis
Data were analyzed using the Statistical Package for the Social Sciences for Windows (version 23.0; IBM Corp., Armonk, NY, USA) and jamovi (version 2.6; the jamovi project, Sydney, Australia). Descriptive statistics (frequency, percentage, mean, and standard deviation) were applied. Pearson’s correlation measured relationships. CFA was conducted in jamovi. Normality was assessed via skewness and kurtosis, with ±1 considered acceptable.36 Statistical significance was set at p<0.05.
Ethical Considerations
Permission was obtained from the original authors of the SQOL to conduct a validity and reliability study. Ethical approval was granted by the Hacettepe University Ethics Committee (GO21/1034), along with institutional permission. (approval number: 2021/20-02, dated: 05.10.2021). Informed consent was obtained from all participants, and the study was conducted in accordance with the principles of the Declaration of Helsinki.
Results
Participants had a mean age of 59.66 (±12.70) years and had lived with ostomies for an average of 16.47 (±21.86) months. Of the sample, 48.8% were men, 50.4% had permanent ostomies, and 48.0% reported income below expenses. Nearly half (45.6%) experienced at least one ostomy-related complication. Most participants (76.8%) contributed financially to ostomy supplies, and 32.0% were receiving chemotherapy. Preoperative ostomy site marking was performed by stoma and wound care nurses in 78.6% of applicable cases. Further demographic and clinical data are presented in Table 1.
Validity Analyses
Content Validity
The CVI for all items of the linguistically validated questionnaire was 1.00, indicating high content validity; therefore, no modifications were made to the items.
Construct Validity
Factor loadings ranged from 0.76 to 0.85 for Elimination Concerns, 0.55 to 0.81 for Psychological Impact, 0.71 to 0.82 for Daily Activities, and 0.78 to 0.93 for Social Relationships. Overall loadings ranged from 0.55 to 0.93, all exceeding the recommended threshold of 0.32 for construct validity.37 The detailed factor structure and factor loadings of the SQOL-TR are given in Table 2.
CFA yielded acceptable fit indices: χ²/df =2.17, CFI =0.92, TLI =0.90, SRMR =0.05, and RMSEA =0.09. These results confirm the construct validity of the SQOL-TR.38 Details are presented in Table 3.
Concurrent Validity
Analysis revealed a significant positive correlation between the SQOL-TR and the O-QOL (r=0.78, p<0.001). This indicates that as QoL scores obtained from the SQOL-TR increased, O-QOL scores also increased, confirming the concurrent validity of the SQOL-TR. Following completion of the validity assessments, reliability analyses were conducted.
Reliability Analyses
The SQOL-TR demonstrated excellent reliability, with a Cronbach’s α of 0.964 and sub-dimension values ranging from 0.846 to 0.947. Composite reliability ranged from 0.852 to 0.949. Coefficients above 0.70 indicate strong reliability.38 The results are presented in Table 4.
Item Analysis
To determine the discriminative power and total score prediction levels of the items, corrected item-total correlations and 27% sub-upper group comparisons were conducted. The t-values between the sub and upper groups ranged from 15.74 to 21.66 for Elimination Concerns, 9.02 to 25.53 for Psychological Impact, 10.73 to 13.29 for Daily Activities, and 17.04 to 30.52 for Social Relationships (p<0.001), indicating significant discriminative power.
Item-total correlations ranged from 0.72 to 0.85 for Elimination Concerns, 0.48 to 0.79 for Psychological Impact, 0.61 to 0.75 for Daily Activities, and 0.74 to 0.88 for Social Relationships. Correlations above 0.30 are considered adequate for discriminative power. These findings confirm that all SQOL-TR items are sufficiently capable of distinguishing the quality being measured. Detailed results are presented in Table 5.
Interpretation of the SQOL-TR Questionnaire Scores
The SQOL-TR consists of 20 items; each is rated on a 4-point Likert-type scale ranging from always (1) to never (4). The questionnaire includes four sub-dimensions: Elimination Concerns (4 items), Psychological Impact (6 items), Daily Activities (4 items), and Social Relationships (6 items). No items were excluded from the final version.
Scores range from 4 to 16 for sub-dimensions with 4 items and from 6 to 24 for those with 6 items. Higher scores on each sub-dimension and the total questionnaire indicate better QoL among individuals with ostomies.
Discussion
This study aimed to evaluate the validity and reliability of the SQOL-TR among individuals with ostomies living in Türkiye. The factor loadings obtained for both the total questionnaire and its sub-dimensions were high. In comparison, the Chinese adaptation of this questionnaire reported overall factor loadings ranging from 0.48 to 0.81.32 In the same study, factor loadings were 0.71-0.75 for Defecation Concerns, 0.52-0.71 for Psychological Impact, 0.48-0.78 for Daily Function, and 0.50-0.83 for Social Relationship.32 The present study demonstrated even higher factor loadings across all sub-dimensions and the total questionnaire, indicating that the SQOL-TR has strong construct validity.
A key condition for establishing construct validity is ensuring model-data fit. In this study, CFA demonstrated fit indices ranging from acceptable to excellent, indicating that the hypothesized four-factor structure fits the data well. These findings are consistent with those from the Spanish29, Canadian31, and Chinese32 adaptations of the questionnaire. Therefore, the structural model validated in the Turkish context is comparable with those observed in previous international adaptations.
Another essential step in cultural adaptation studies is to demonstrate concurrent validity by correlating the adapted scale with an instrument already accepted as valid and reliable within the same cultural context.31 In this regard, the O-QOL, adapted to Turkish by Karadağ et al.22, is a well-established tool for measuring QoL in Turkish patients with ostomies. The current study found a considerable positive correlation between the SQOL-TR and the O-QOL, supporting the claim that the SQOL-TR accurately measures QoL among patients with ostomies.
Internal consistency, measured through Cronbach’s α and composite reliability, is one of the most frequently used techniques in scale validation.22, 23, 37 In this study, the SQOL-TR demonstrated excellent reliability, with Cronbach’s α and composite reliability values exceeding conventional thresholds. The internal consistency of the original English version was reported as 0.9227, whereas the Italian23, Spanish29, Brazilian30, Canadian31, and Chinese32 adaptations reported coefficients of 0.90, 0.86, 0.87, 0.93, and 0.93, respectively. Based on these findings, the SQOL-TR appears to exhibit the highest internal consistency among the culturally adapted versions of the questionnaire.
Although item discriminative power analysis is a commonly used method to evaluate reliability,37, 38 it was not reported in the original development study or in most adaptation studies. However, the current study included item discriminative power analysis and found that all items in the SQOL-TR significantly differentiated between sub and upper scoring groups. These results support the instrument’s ability to detect variation across different levels of perceived QoL, indicating that the items are also reliable at the item level.
Limitations and Strengths of the Study
This research has some limitations. First, this was a single-center study. Second, the psychological state of the patients during the interviews may have influenced the data obtained. The sample consisted of 125 participants, drawn from the 132 patients with ostomies followed up at the study center within 1 year.
Although limited by low survival rates, this sample size is notable compared with previous studies: 182 participants across four European countries in the original development27, 251 from 73 centers in Italy23, 125 in Spain29, 111 in Brazil30, and 120 in Canada31. Reaching this number in a single center within 1 year reflects a strength of this study.
Conclusion
The SQOL-TR is a user-friendly, multidimensional, and objective tool for healthcare professionals working with patients with ostomies (Supplementary file). This adaptation confirmed its validity and reliability for individuals with colostomy, ileostomy, or urostomy. It is recommended for use in clinical and multinational studies as a standardized QoL assessment instrument.
