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Corresponding author: Shiow-Li Hwang, RN, DNSc, Professor and President, Chang Gung Institute of Technology, Taoyuan, Taiwan, 261, Wen-hwa 1st Rd, Kwei-shan, Taoyuan, Taiwan 333 (e-mail: tyhuang{at}gw.cgit.edu.tw).
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Abstract |
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Objective To validate the Chinese version of the Modified Pulmonary Functional Status and Dyspnea Questionnaire.
Methods The Chinese version was developed by using translation and back translation and was tested in Taiwan in 88 patients who had heart failure but no pulmonary disease or comorbid conditions limiting physical function. Data on a Taiwanese subsample (n=30) were compared with data on 30 patients in the United States matched by sex, age, and severity of disease to determine the equivalence of the Chinese and English versions. Construct validity was assessed by testing the hypothesis that health-related quality of life measured by using the Minnesota Living With Heart Failure Questionnaire is associated with the score on the dyspnea questionnaire. Reliability was assessed by using the Cronbach 
and item-total correlations.
Results Equivalence between the US and Taiwanese samples was high, from 0.67 to 0.91 for each item of the questionnaire and for the total score. Satisfactory correlations between the Chinese dyspnea and the Minnesota questionnaires, especially in the physical dimension (r=0.71, P<.001), provided support for the construct validity of the Chinese questionnaire. Reliability of the Chinese questionnaire was adequate (=0.94).
Conclusions The Chinese Modified Pulmonary Functional Status and Dyspnea Questionnaire is a reliable and valid measure for dyspnea that can be used in Taiwanese patients with heart failure.
Dyspnea can be conceptualized as multidimensional, with components that include frequency, severity, and distress related to experiencing it.9 Furthermore, dyspnea is correlated with health-related quality of life (HRQOL), which is a person’s perception of the overall effect of a health condition on daily life.3,10 Effective symptom management requires assessment of the multiple dimensions of a symptom, not merely the presence or absence of the symptom.
Approximately 5.2 million persons in the United States have heart failure, and 550000 new cases are diagnosed annually.11 The estimated direct and indirect cost of heart failure in the United States for 2007 was $33.2 billion.11 Although no similar information on the prevalence, incidence, or cost of heart failure in Taiwan is available, vital statistics data12 indicate that cardiac disease has been the second most common cause of death in Taiwan since 2004. Because every cardiovascular problem can lead to cardiac failure, this chronic condition results in substantial use of medical resources. This trend suggests that heart failure could become the most costly chronic illness in Taiwan.
Effective treatment goals for patients with heart failure include symptom management. Thus, symptom evaluation is fundamental to improving outcomes. A valid, reliable, sensitive, and cross-cultural measure of dyspnea is important to facilitate comparisons of this symptom between patients of different cultures. The most efficient method of developing a cross-cultural measure is translating an existing reliable, valid, sensitive English measure of dyspnea. Several instruments include dyspnea, but none measures the multidimensionality of dyspnea in heart failure or focuses solely on dyspnea in heart failure.
The purpose of this research project was to translate the Modified Pulmonary Function Status and Dyspnea Questionnaire (PFSDQ-M) from English into Chinese and to test the psychometric properties of the Chinese version in patients in Taiwan who have heart failure. The specific aims of the study were to develop the Chinese translation of the PFSDQ-M and show equivalence between 2 monolingual samples, test the reliability of the Chinese PFSDQ-M, and test the validity of the Chinese version, including content validity and construct validity.
| Dyspnea is the most common and distressing symptom for patients with heart failure.
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Methods |
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Measurements
Dyspnea was measured by using the PFSDQ-M. This instrument was developed in 1994 for use with patients with chronic obstructive pulmonary disease (COPD) and was modified in 1998.13,14 Although the instrument was developed for use in COPD, it is not specific to patients with this disease and can be used in other populations in whom dyspnea occurs. Caroci and Lareau15 used the PFSDQ-M to compare patients with heart failure (n = 30) and COPD (n = 30) and found that the 2 groups did not differ in the frequency of dyspnea but did differ in the intensity of the symptom and in some of the terms used to describe dyspnea.
| To measure dyspnea among cultures, a valid, reliable, sensitive, and cross-cultural measure is required.
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The PFSDQ-M measures dyspnea on the basis of patients’ subjective perception of the symptom and consists of assessment of the main components of the symptom. The PFSDQ-M reflects the frequency, severity, and distress associated with dyspnea. The instrument consists of 5 general questions on the experience of dyspnea, the frequency of its occurrence during the preceding month, and the overall intensity of shortness of breath (ie, on most days, today, and with usual activity levels). Ten other questions are related to the intensity of dyspnea, rated on a scale from 0 to 10, when different activities are performed. Higher scores indicate more severe dyspnea.
These items also indirectly reflect distress related to dyspnea. The psychometric reliability of the PFSDQ-M has been established in English-speaking populations; the scale internal consistencies were moderate to high. The PFSDQ-M has acceptable internal consistency and stability.14,16–18
With the agreement of the original developer of the measure, the Chinese version of the PFSDQ-M was developed via translation and back translation. Chinese is not a single language. The Chinese written language can be categorized as traditional or simplified. In Taiwan and Hong Kong, the Chinese used is traditional Chinese. In mainland China, simplified Chinese is used. Even among these groups, the type of Chinese spoken varies. The Chinese version of the PFSDQ-M was translated for use by persons who read traditional Mandarin Chinese, as do persons living in Taiwan. Ultimately, however, language is not the only issue that must be considered. The cultural context relevant to those who will be using the instrument must be reflected in the translation.
| Both semantic and cultural equivalence should be considered in the translation process.
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In order to secure adequate, equivalent, and culturally relevant meaning of words and expressions, development of the Chinese version of the PFSDQ-M included the following stages. Stage 1 consisted of forward translation performed by 2 bilingual translators. One translator was an experienced cardiac nurse and an expert in nursing research on cardiovascular disease; the other was an expert in English and had no medical background. Stage 2 consisted of a synthesis of the 2 translations (by T.-Y.H.). Stage 3 was a back translation performed by 2 bilingual native Taiwanese translators who have resided in the United States and Australia for more than 15 years. Both bilingual translators were experienced nurse specialists familiar with patients with dyspnea. Stage 4 consisted of expert review by a committee composed of 3 members: 2 nurse specialists and 1 cardiologist. In stage 5, the back-translated PFSDQ-M was sent to the developer of the original measure to obtain her opinion. After completion of these stages, the Chinese version of the PFSDQ-M was established.
Establishing reliability and validity included demonstrating internal consistency, conceptual equivalence, content validity, and construct validity. Internal consistency was estimated by using the Cronbach and item-total correlations. Conceptual equivalence was established by correlating the PFSDQ-M scores of the Taiwanese patients with the scores of the US patients.
Content validity was based on the opinions of a review by an expert panel of cardiac clinical experts (2 nurses and 1 cardiologist). Each expert reviewed each item of the Chinese PFSDQ-M and evaluated the appropriateness or the item as part of the scale by using scores from 1 (very inappropriate) to 5 (very appropriate). The percentage of acceptance of and mean score for each item were calculated.
Construct validity was established by testing the hypothesis that HRQOL measured with the Minnesota Living With Heart Failure Questionnaire (MLHFQ) is at least modestly associated with PFSDQ-M scores. The MLHFQ is a 21-item, disease-specific measure of the quality of life for patients with heart failure. Each item is scored on a scale ranging from 0 to 5; the total score ranges from 0 to 105. Higher scores indicate poorer HRQOL. Psychometric properties were excellent in previous studies.19,20 The Chinese MLHFQ, which has excellent psychometric properties,21 was used in this study.
Procedures
Approval for the study was obtained from the appropriate institutional review boards of National Taiwan University Hospital, Taipei. Informed consent was obtained from each patient after exhaustive explanation of the study by the data collector. Some patients filled out questionnaires by themselves, and some were assisted by the investigator (T.-Y.H.). Patients required 5 to 10 minutes to finish the entire questionnaire packet.
Secondary data from 30 US patients with heart failure15 were compared with data from a subsample of the Taiwanese patients (n=30) to determine equivalence. These 30 patients were matched with the US patients on the basis of sex, age, ejection fraction, and New York Heart Association class of heart failure.
Data Analysis
After data entry, the data file was checked for accuracy and was analyzed by using SAS software (SAS Institute Inc, Cary, North Carolina). Reliability was tested by using the Cronbach and corrected item-total correlations. In a reliable instrument, the majority of the item-total correlations are greater than 0.30, meaning that the item contributes to the scale,22 and the Cronbach should be greater than 0.7 to reflect satisfactory internal consistency.
Equivalence is a form of validity that refers to the agreement between 2 measures of the same construct. Equivalence can be considered operational and cultural. Operational equivalence consists of content, semantic, and technical equivalence and ensures that the original measurement of the construct in question is maintained. Cultural equivalence ensures that the items in the instrument are not biased toward one of the cultures in a study that includes participants from more than one culture.23,24 Operational and cultural equivalence were considered during each phase of the translation and data analysis to maintain the integrity of the instrument.
Pearson correlations for continuous data and Yule’s Q for nominal data were used to examine conceptual equivalence between the 30 US patients and the 30 matched Taiwanese patients. For validity, the results of hypothesis testing were examined by using Pearson correlations to determine the relationship between PFSDQ-M scores and MLHFQ scores. An instrument with construct validity should yield the expected results from testing a hypothesis that has been supported in other studies.
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Results |
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). Most of the patients were male, were retired, and lived with and were cared for by family. The 30 US patients were matched with the 30 Taiwanese patients for age, sex, ejection fraction, and New York Heart Association class of heart failure. Descriptive statistics for the PFSDQ-M are displayed in Table 2. The mean total score for the MLHFQ in the Taiwanese sample was 43.8 (SD, 25.1; range, 0–105), the mean for the physical subscale was 17.7 (SD, 10.8; range, 0–40), and the mean for the emotional subscale was 11.4 (SD, 7.4; range 0–25).
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| The Chinese version of the Modified Pulmonary Functional Status and Dyspnea Questionnaire is a reliable and valid instrument for patients with heart failure.
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Translation and Equivalence
The original PFSDQ-M items and the back-translated items were reviewed by experts and the developer of the PFSDQ-M. Instead of similarity of wording, the experts considered content equivalence in their review. The new back-translated English version of the PFSDQ-M showed no significant deviation from the original English version. Only a few small language changes had to be made for the 2 versions to have a high degree of correspondence.
All but 1 item in these 2 versions of the questionnaire had cultural equivalence. In field testing, male Taiwanese patients responded to the item "preparing snack" with "no such experience." This response was quite different from that of male US patients, who were able to provide a rating of the activity. This finding reflects cultural differences in performing this activity. Cultural equivalence on the PFSDQ-M between the 30 Taiwanese patients and the 30 US patients was excellent (Table 3). Therefore, both operational and cultural equivalence were established.
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for the PFSDQ-M was 0.94. This finding indicates the internal consistency of the scale. The corrected item-total correlations (Table 2
) ranged from 0.453 to 0.886. This finding indicates that all items contributed to the scale (because their correlations were greater than 0.30) but were not redundant (because their correlations were less than 0.886).22
Validity
After review and discussion, the 5 experts rated all items in the PFSDQ-M for the expert validity index analysis. All questions yielded 100% agreement, including ratings of 5 for very acceptable and 4 for acceptable on all questions. Thus, content validity was excellent.
Moderately high correlations between MLHFQ scores and PFSDQ-M scores, especially in the physical dimension (r = 0.71, P < .001), provided support for the construct validity of the Chinese PFSDQ-M (Table 4). Patients with more severe dyspnea had worse HRQOL, as indicated by higher total MLHFQ scores, and higher physical and emotional dimension scores. The lower correlation of the PFSDQ-M scores with the emotional dimension scores of the MLHFQ compared with the physical dimension scores attests further to the construct validity of the PFSDQ-M.
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Discussion |
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Measurement of patient-centered outcomes is a central issue in nursing research, but cultural and linguistic variations between English and Mandarin make translating instruments difficult. Not only semantic but also cultural equivalence must be considered in the translation process. Therefore, using an ideal procedure to translate an instrument into another (target) language is essential. The most widely used and accepted method for developing equivalence between the original language and the target language is back translation. The material in the original language is first translated into the target language, then the material in the target language is translated back to the original language and the 2 original-language versions are compared.23 The Chinese version of the PFSDQ-M was developed by conscientious application of this process.
Except for the item on preparing a snack, all items of the dyspnea scale of the PFSDQ-M had excellent linguistic similarity and cultural equivalence. Half of the male Taiwanese patients answered this item with "have no experience doing that." In Taiwan, especially among the elderly, men seldom prepare food for their family or even for themselves. In translating an instrument to be used by both sexes, all of the items should be applicable to both.
Perspectives differ on using bilingual or monolingual participants to test translated questionnaires. In our study, use of monolingual participants was a valuable way to assess the equivalence of the Chinese PFSDQ-M. Candell and Hulin26 asserted that use of bilingual participants in checking for equivalence is not appropriate because the participants may be using both languages when responding to the translated questionnaire. The bilingual participants’ understanding of both languages and the contexts for use of these languages could result in no detection of item biases that would be more evident to monolingual participants. We used comparison between 2 monolingual groups and confirmed strong correlations. Thus, symptom comparison among groups from different cultures and with different diseases is possible.
Reliability
Our evaluation was the first one of the Chinese PFSDQ-M in Taiwanese patients with heart failure. Our findings are similar to those of previous studies in patients with COPD. The item-total correlations and the coefficients support good internal consistency of the Chinese PFSDQ-M.
Validity
The correlation between the Chinese PFSDQ-M scores and the MLHFQ scores provides strong support for the construct validity of this PFSDQ-M. Patients with heart failure can have marked impairments in functional status, multiple hospital admissions, high mortality, multiple physical and psychological signs and symptoms, and a poor HRQOL.2,3 The prevalence and impact of signs and symptoms may be the most important predictors of impaired HRQOL; the relationship between signs and symptoms and quality of life in patients with heart failure has been confirmed in previous studies.1,2 The relationship between dyspnea and HRQOL in our study supports these previous findings.
In the original validation study14 for the PFSDQ-M, construct validity was established by determining the relationship between PFSDQ-M scores and the results of pulmonary function testing. As would be expected on the basis of previous studies, we found that the relationship between PFSDQ-M scores and scores on the physical dimension of the MLHFQ was stronger than the relationship between PFSDQ-M scores and scores on the emotional dimension of the MLHFQ. Although dyspnea is distressing and negatively affects the emotional aspects of HRQOL, its greatest impact appears to be on patients’ abilities to engage in desired physical activities.
| Patients awaiting revascularization procedures report that uncertainty and fear were more disturbing than chest pain.
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ACKNOWLEDGMENTS |
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FINANCIAL DISCLOSURES
None reported.
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