Psychometric Properties of the Traditional Chinese Version of the Venous Leg Ulcer Quality of Life Questionnaire

INTRODUCTION

Patients with venous leg ulcers (VLUs) experience various concurrent psychoneurological symptoms including leg swelling, skin irritation, itchiness, pain, depression, fatigue, anxiety, and sleep disturbance. These symptoms and the long-term continuing presence of the VLU not only affect patients’ quality of life (QoL) but also limit disease self-management, functional status, and work patterns.1 In Western countries, the QoL of patients with VLUs is often prioritized and has been measured using the following tools: the Medical Outcomes Study 36-item Short-Form Health Survey (SF-36), Skindex-29, Charing Cross Venous Ulcer Questionnaire, and Chronic Venous Insufficiency Quality of Life Questionnaire.2–5 However, in Taiwan, most medical professionals concentrate on treating VLU wounds in isolation rather than examining the multiple factors related to poor QoL among patients with VLU. There is no QoL tool for these patients that considers the linguistic and cultural specificities of Taiwan.

The Venous Leg Ulcer Quality of Life Questionnaire (VLU-QoL)6 has shown good reliability and validity and been translated into Brazilian Portuguese (Cronbach α = .94; test-retest reliability = 0.78)7 and simple Chinese (Cronbach α = .94; interexpert reliability = 0.84; test-retest reliability = 0.83).8 A systematic review conducted by Liu et al9 on QoL tools for patients with VLUs describes the provisional recommendation of using the VLU-QoL in clinical practice and research. However, the aforementioned simplified Chinese version of the VLU-QoL is not suitable for the Taiwanese context, in which the common language is traditional Chinese. Whereas simplified Chinese often uses a single character to represent words with different meanings but the same pronunciation, traditional Chinese has separate characters for each word, and each character represents a particular concept or cultural foundation and style.

Considering these linguistic and cultural differences and the need to improve QoL in patients with VLU, this study aimed to translate the original English version of the VLU-QoL into traditional Chinese and evaluate the psychometric properties of this translated version among Taiwanese patients with VLU. The final goal of this study was to deliver a valid and reliable questionnaire for use by healthcare professionals to inform the development of QoL interventions for these patients.

METHODS

Patients were included if they were 20 years or older, conscious, could communicate in Mandarin or Taiwanese, and indicated willingness to participate by signing an informed consent form. Detailed information pertaining to the inclusion and exclusion criteria, sample size, data collection process, and institutional review board approval (no. IRB 2019048) is reported elsewhere.10 The processes of translation, cultural adaptation, and validation of the psychometric properties of the traditional Chinese version of the VLU-QoL followed the methods outlined in prior research11 and are described below.

Scale-Translation Process Original VLU-QoL

The VLU-QoL, developed in the UK by Hareendran et al,6 is a scale based on qualitative interviews and group discussions with outpatients with VLUs. The tool uses Skindex-29, a skin-related QoL questionnaire, as a template. The VLU-QoL is a 15-minute, 34-item questionnaire that measures the patient’s QoL via three constructs: Activities, Psychological, and Symptom Distress. Measures include wound condition, pain duration, social impact, activity impact, appearance impact, and emotional status over the most recent 4 weeks. Items are scored on a 5-point Likert-type scale, where 0 = never, 1 = rarely, 2 = sometimes, 3 = often, and 4 = all the time. The subtotal score for the Activities construct is calculated by multiplying the sum of the scores for items 1 through 12 by 100/48. Similarly, the subtotal scores for the Psychological and Symptom Distress constructs are calculated by multiplying the sum of the scores for items 13 through 24 by 100/48 and items 25 through 34 by 100/40, respectively. The subtotal score for each construct ranges from 0 to 100, with a higher score indicating lower QoL. Cronbach α values for the three constructs are .85, .83, and .86, respectively.

Forward and back translation

After obtaining consent from Hareendran et al,6 one of the authors who was knowledgeable about VLUs translated the English version into traditional Chinese. Next, two professors of nursing, both of whom had overseas-study experience and high English proficiency, were independently invited to discuss and revise the translation to ensure both consistency with the meaning in the original tool and ease of comprehension. The product of this forward translation process was the preliminary version of the traditional Chinese VLU-QoL.

Following this, the researchers asked two professional experts with medical and health-related backgrounds who were not familiar with the original version of the VLU-QoL to independently translate the preliminary version of the traditional Chinese VLU-QoL back into English. The principal investigator compared the format, wording, sentence structure, meaning, and relevance of the two back-translated versions with those of the original VLU-QoL.

In the final step, three bilingual nursing professors and one expert in back translations discussed the contents of the available versions to ensure linguistic consistency, identify any discrepancies regarding the cultural meaning and idioms in the phrasings, confirm the accuracy of wording and grammatical structure of the sentences, and define the response format;11 this process led to a prefinal version of the traditional Chinese VLU-QoL.

The content validity index (CVI) was used to confirm whether the items in the prefinal version appropriately reflected the constructs to be measured (Activities, Psychological, and Symptom Distress).12 Five healthcare professionals (three attending plastic surgeons, one attending cardiovascular surgeon, and one plastic surgery nurse specialist) with an average of more than 15 years of experience independently examined the fitness of the scale items for its purpose and the clarity and completeness of the scale regarding the study objectives. Item-level CVI (I-CVI) and scale-level CVI (S-CVI) were evaluated separately on Likert-type scales as follows: a score of 4 was very appropriate, 3 was strong consensus in favor of making a small adjustment, 2 was the need to make a significant adjustment, and 1 was inappropriate. Items scored 3 or higher were considered appropriate, whereas items scored 1 or 2 were flagged for modification or deletion based on the experts’ evaluations and suggestions.

The I-CVI and S-CVI were calculated based on the proportions of the items that were scored 3 or higher. For the prefinal version of the traditional Chinese VLU-QoL, the I-CVI ranged from 0.8 to 1.0 (except for item 12; I-CVI = 0.7), and the S-CVI was 0.98, indicating good content validity. Based on expert feedback, item 12 was revised from “My leg ulcer/s disrupts my everyday life” to “Treatment for my leg ulcer/s disrupts my everyday life.” In this step, the final version of the traditional Chinese version of the VLU-QoL was confirmed.

Psychometric testing of the final version

The psychometric tests used in this study included internal consistency reliability, test-retest reliability, convergent and discriminant validity, and criterion-related validity. Qualified participants independently completed the final version of the traditional Chinese version of the VLU-QoL. For participants who were illiterate, an author provided assistance by reading the questions and filling out their answers.

To determine test-retest reliability, the first 36 recruited participants completed the same questionnaire again 21 days after the first round. The test-retest reliability period for the traditional Chinese version of the VLU-QoL was set at 21 days; in contrast, the test-retest reliability period for the Brazilian version of the VLU-QoL7 was set at 60 days and at 48 to 72 hours for the simplified Chinese version.8 This was because the enrolled patients underwent follow-up examinations every 3 weeks, a timeframe in which their VLU wounds healed slowly with little change.

The criterion-related validity was measured by the simultaneous administration of the Taiwanese version of the Medical Outcomes Study SF-36. The SF-36 has been widely used to assess patient QoL as a prognostic indicator of health and is available in many languages.13 Its Taiwanese version, developed by Prof Ju-Fen Rachel Lu,14 comprises eight dimensions: physical functioning, role limitations due to physical health problems, bodily pain, general health, vitality, social functioning, role limitations due to emotional problems, and mental health. In this study, item 2, which explores the relationship between QoL and health a year ago, was not used for scoring. The remaining 35 items were aggregated into two summary measurements: physical component summary (PCS) and mental component summary (MCS). The PCS score was calculated from the dimensions of physical functioning, role limitations due to physical health problems, bodily pain, and general health, and the MCS score was calculated from vitality, social functioning, role limitations due to emotional problems, and mental health. Scores for the eight dimensions range from 0 (worst) to 100 (best) following the formula provided by Stewart and Ware.15 After formula conversion, the higher the score, the higher the QoL. The Cronbach α values for the eight dimensions of the Taiwanese version of the SF-36 ranged from .8 to .9 in the general population,14 with a 2-week test-retest reliability of 0.89 for the PCS and 0.76 for the MCS.16

Statistical Analysis

Data analysis was performed using statistical software SPSS 21.0 and AMOS 21.0 (IBM). The participants’ demographic attributes were expressed as mean and SD or as percentages. The scale’s test-retest reliability and criterion-related validity were measured using the Pearson product-moment correlation coefficient. The scale’s internal consistency and reliability were measured with Cronbach α, and convergent validity and discriminant validity were assessed via confirmatory factor analysis.

RESULTS

In total, 167 patients with VLU were enrolled in this study. Participants’ mean age was 67.08 (SD, 14.25; range, 31–99) years. Of the 167 participants, 86 (51.5%) were women, 108 (64.7%) were unemployed, 107 (64.1%) were married, 61 (36.5%) had an elementary school education, 35 (21%) were illiterate, 124 (73.4%) had no history of venous surgery, 94 (56.3%) had one ulcer, 49 (29.3%) had an ulcer duration of more than 1 year, and 49 (29.3%) had ulcers greater than 6 cm2 in size.

Reliability Internal consistency reliability

The overall internal consistency reliability of the traditional Chinese version of the VLU-QoL measured by Cronbach α was .95. The Cronbach αs for the Activity, Psychology, and Symptom Distress constructs were .94, .92, and .94, respectively, indicating that the consistency requirement was met.

Test-retest reliability

The overall test-retest reliability was 0.98. The test-retest reliability values for the Activity, Psychology, and Symptom Distress constructs were 0.99, 0.96, and 0.98, respectively, indicating high stability reliability.

Validity Confirmatory factor analysis

In assessing the convergent and discriminant validity of the traditional Chinese version of the VLU-QoL, confirmatory factor analysis showed that the standardized factor loadings of all items ranged from 0.12 to 0.96. The composite reliability values of the Activity, Psychology, and Symptom Distress constructs were 0.93, 0.92, and 0.85, respectively. Their average variances extracted were 0.56, 0.50, and 0.41, respectively, indicating that the items within the Activity and Psychology constructs were well aggregated on the underlying factors. However, the average variance extracted for the Symptom Distress construct was low (0.41), and the items within this construct failed to aggregate well on the underlying factors. Items 30 through 34 showed especially low standardized factor loadings, as follows: “The itching around my leg ulcers bothers me” (item 30; factor loading, 0.21); “The skin around my leg ulcers annoys me very much” (item 31; factor loading, 0.32); “The skin around my leg ulcers is very sensitive” (item 32; factor loading, 0.23); “The smell from my leg ulcers bothers me” (item 33; factor loading, 0.43); and “The oozing blood or exudate from my leg ulcers bothers me” (item 34; factor loading, 0.41; Table 1 and Figure).

Table 1 - CONFIRMATORY FACTOR ANALYSIS (N = 167) Construct Item Estimates of Model Parameters Convergent Validity Nonstandardized Factor Loading Standardized Estimates P Standardized Factor Loading R 2 Composite Reliability Average Variance Extracted Activity Q1 1.00 0.92 0.85 0.93 0.56 Q2 1.05 0.04 <.01 0.96 0.93 Q3 1.04 0.04 <.01 0.96 0.92 Q4 1.08 0.04 <.01 0.96 0.93 Q5 0.89 0.06 <.01 0.78 0.61 Q6 0.93 0.06 <.01 0.81 0.65 Q7 0.84 0.10 <.01 0.55 0.30 Q8 0.18 0.13 .14 0.12 0.01 Q9 0.92 0.08 <.01 0.70 0.49 Q10 0.95 0.07 <.01 0.75 0.57 Q11 0.45 0.13 <.01 0.26 0.07 Q12 0.73 0.08 <.01 0.63 0.39 Psychology Q13 1.00 0.79 0.62 0.92 0.50 Q14 1.04 0.09 <.01 0.81 0.66 Q15 1.02 0.08 <.01 0.84 0.71 Q16 0.54 0.08 <.01 0.49 0.24 Q17 1.03 0.09 <.01 0.80 0.64 Q18 0.84 0.09 <.01 0.66 0.44 Q19 1.04 0.09 <.01 0.79 0.63 Q20 0.89 0.10 <.01 0.63 0.40 Q21 0.76 0.10 <.01 0.58 0.33 Q22 1.00 0.09 <.01 0.78 0.61 Q23 1.06 0.10 <.01 0.77 0.59 Q24 0.63 0.10 <.01 0.49 0.24 Symptom distress Q25 1.00 0.82 0.67 0.85 0.41 Q26 0.80 0.07 <.01 0.74 0.55 Q27 0.71 0.07 <.01 0.72 0.52 Q28 1.10 0.07 <.01 0.96 0.93 Q29 1.12 0.07 <.01 0.96 0.92 Q30 0.25 0.10 <.05 0.21 0.04 Q31 0.37 0.09 <.01 0.32 0.10 Q32 0.24 0.08 <.001 0.23 0.05 Q33 0.53 0.09 <.01 0.43 0.19 Q34 0.54 0.10 <.01 0.41 0.17 Suggested values >0.6 0.5–0.95 >0.6 >0.5
F1Figure:

CONFIRMATORY FACTOR ANALYSIS

Regarding discriminant validity, the average variances extracted for the three constructs were 0.75, 0.71, and 0.64, respectively, indicating that the items in all constructs diverged well from the underlying factors. The model’s overall goodness of fit, measured by the χ2 value divided by the degrees of freedom, was 4.16 (P < .001), indicating a high goodness of fit and independence of the model’s explanatory power from model complexity (Table 2).

Table 2 - SUMMARY OF THE OVERALL MODEL GOODNESS OF FIT (N = 167) Test Statistics Fit Indicators χ 2 (df) χ 2 /df GFI RMR RMSEA AGFI NFI CFI RFI Goodness-of-fit criteria The smaller the better 1–5 >0.90 <0.05 0.05–0.08 >0.90 >0.90 >0.90 >0.90 Original scale 2,179.67 (524) 4.16 0.55 0.20 0.14 0.49 0.63 0.69 0.60

Abbreviations: AGFI, adjusted goodness-of-fit index; CFI, comparative fit index; GFI, goodness-of-fit index; NFI, normed fit index; RFI, relative fit index; RMR, root mean square residual; RMSEA, root mean square error of approximation.


Criterion-related validity

The traditional Chinese version of the VLU-QoL and the Taiwanese version of the SF-36 were administered simultaneously to facilitate correlation analysis. The correlation coefficient (r) ranged from −0.7 to −0.2 (P < .001), indicating good criterion-related validity for the traditional Chinese version of the VLU-QoL (Table 3).

Table 3 - CRITERION-RELATED VALIDITY OF THE TRADITIONAL CHINESE VERSION OF THE VLU-QOL COMPARED WITH THE TAIWANESE VERSION OF THE SF-36 (N = 167) Taiwanese Version of the SF-36 Traditional Chinese Version of the VLU-QoL Activities Psychological Symptom Distress Physical component summary −0.66a −0.31a −0.38a Mental component summary −0.37a −0.51a −0.37a  Physical functioning −0.59a −0.29a −0.25a  Role limitations because of physical health problems −0.60a −0.39a −0.31a  Bodily pain −0.42a −0.45a −0.70a  General health −0.56a −0.31a −0.20a  Vitality −0.54a −0.38a −0.37a  Social functioning −0.63a −0.50a −0.44a  Role limitations because of emotional problems −0.41a −0.50a −0.37a  Mental health −0.31a −0.37a −0.32a

Abbreviations: SF-36, 36-item Short-Form Health Survey; VLU-QoL, Venous Leg Ulcer Quality of Life Questionnaire.

aP < .001.


DISCUSSION Reliability

The overall Cronbach α of the traditional Chinese version of the VLU-QoL was .95, and the Cronbach αs for the Activity, Psychology, and Symptom Distress constructs were .94, .92, and .94, respectively. These results are in line with those of the study by Hareendran et al,6 who used the original scale to survey 124 patients with VLU in the UK and observed that the scale had an overall Cronbach α > .8, whereas the three constructs had Cronbach α values of .85, .83, and .86, respectively. Further, Araújo et al7 translated the VLU-QoL into Portuguese and surveyed 82 patients with VLU, and a China-based study8 translated the VLU-QoL into simplified Chinese and surveyed 182 patients with VLU. Both studies found that the scale’s overall Cronbach α was .94, thus showing a value similar to that in the current study (.95) and indicating the good internal consistency reliability of the scale.

The overall test-retest reliability value was 0.98 and the values for the three constructs were greater than 0.96, indicating that they were highly stable. These results show values that were higher than those for the Brazilian version (0.78, P < .01)7 and the simplified Chinese version of the VLU-QoL (0.83).8 The high test-retest stability of the traditional Chinese version of the VLU-QoL, even as it was applied 21 days after the first survey round, may be explained by the fact that most patients’ disease conditions did not change significantly during the 21-day period.

Validity

The traditional Chinese version of the VLU-QoL demonstrated good content validity in terms of S-CVI (0.98) and I-CVI (0.70–1.00). These results are similar to those of the study by Gu et al8 (I-CVI = 0.83–1.00) pertaining to the simplified Chinese version of the VLU-QoL, which was tested on 182 patients with VLU. The traditional Chinese version of the VLU-QoL also demonstrated good criterion-related validity, which was similar to that of the original scale.6

The traditional Chinese version of the VLU-QoL demonstrated good discriminant validity for the overall scale and its three constructs, as well as a good convergent validity for the Activity and Psychology constructs. However, the Symptom Distress construct failed to aggregate well on the underlying factors, especially for items 30 through 34. The reasons for this finding may be attributed to the following: (1) the research site hospital has widely adopted advanced wound-care dressings for patients with VLU that absorb wound exudate and improve itching, allergies, and odor; and (2) Hareendran et al6 developed the original VLU-QoL in 2007 when not as many dressing options existed. The integration of these two descriptions implies that the factor explanatory power discrepancy is due to wound care innovations that were developed in the past 15 years. However, some studies have shown that VLU-induced phlebitis produces a large amount of wound exudate, leading to various symptoms in leg ulcers, thereby affecting QoL.3 Therefore, a clear decision on whether items 30 through 34 should be retained in the traditional Chinese version of the VLU-QoL requires more evidence.

Limitations

This was a cross-sectional study. Owing to time, workforce, and funding constraints, data were collected exclusively from patients with VLU at one hospital in southern Taiwan, hindering generalizations of these findings to the general population. The test results did not meet or approach the values predicted by structural equation modeling,17 indicating that room for improvement remains regarding sample size and the number of items in the traditional Chinese version of the VLU-QoL.

CONCLUSIONS

The present study was the first to translate the original English version of the VLU-QoL developed by Hareendran et al6 into traditional Chinese. The psychometric tests confirmed that the traditional Chinese version of the VLU-QoL had good reliability and validity and thus may serve as a reference instrument for assessing and studying the QoL of patients with VLU in Taiwan. Use of this version of the VLU-QOL in clinical settings may also help facilitate rapid interprofessional communication, lead to deeper insights into the impact of VLU on QoL, and enable the well-informed development of in-service education programs and appropriate clinical care measures for improving the QoL of patients with VLU. The scale could be administered at medical institutions of various levels or with varying care providers, such as plastic surgery and cardiovascular surgery clinics and wound care centers for the sake of comparison, and these related data may also help improve our understanding of the QoL of patients with VLU, increase the diversity of the study population, and provide a more objective means of verifying the scale’s fitness for its purposes before researchers revise the traditional Chinese version of the VLU-QoL.

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