Copyright B 2015 Wolters Kluwer Health | Lippincott Williams & Wilkins

Changrong Yuan, PhD, RN Huijuan Qian, MSN, RN Jichuan Wang, PhD Elise L. Lev, EdD, RN Avery Yuan, BS Pamela S. Hinds, PhD, RN, FAAN

Factorial Structure of a Scale Strategies Used by People to Promote HealthYChinese Version

K E Y

W O R D S

Background: The Strategies Used by People to Promote Health (SUPPH) is

Cancer patient

an instrument used to measure self-reported self-efficacy in patient populations.

Chinese version of the Strategies Used by People to Promote Health

Self-efficacy has a major impact on quality of life and psychological well-being.

Confirmatory factor analysis (CFA)

Previous findings of dimensionality of the SUPPH vary, and cultural differences exist suggesting the need for further investigation and psychometric testing to establish construct validity of the SUPPH in different cultures. Objective: The purpose of this

Higher-order CFA

study was to examine the factorial structure of the Chinese version of the SUPPH

Self-efficacy

(C-SUPPH). Methods: Using reports from 764 oncology patients in China, the

Strategies Used by People to Promote Health

factorial structure of the C-SUPPH was assessed via 2 analytical strategies. First-order confirmatory factor analysis (CFA) models were used to examine the dimensionality of the C-SUPPH; a second-order CFA was used to determine the existence of a factorial structure hierarchy of the C-SUPPH. Results: Compared with the 2- and 4-factor solutions, the 3-factor CFA of the C-SUPPH had a better fit with the data (comparative fit index = 0.94, Tucker-Lewis index = 0.94, root-mean-square error of approximation = 0.05, the close-fit test P = .565, and standardized root-mean-square residual = 0.04). Our findings confirmed the 3-scale structure: Positive Attitude, Stress Reduction, and Making Decisions; together, the

Author Affiliations: School of Nursing, Second Military Medical University, Shanghai, China (Dr Yuan); Orthopedics Department, Shanghai Jiaotong University Affiliated Sixth People’s Hospital, China (Ms Qian); Department of Nursing Research and Quality Outcomes and the Center for Translational Science, Children’s National Medical Center, School of Medicine, the George Washington University, Washington, DC (Drs Wang and Hinds); College of Nursing, Rutgers University, Newark, New Jersey (Dr Lev); and Chemistry and Biochemistry Department, Suffolk University, Boston, Massachusetts (Ms Yuan). Dr Yuan and Ms Qian contributed equally to this study; therefore, they are both first authors. Dr Yuan was the principal investigator and mentor of this research project who was responsible for the entire study design and the drafting of the manuscript. Ms Qian performed the data collection and manuscript drafting. Dr Wang

Factorial Structure of C-SUPPH in Chinese Cancer Patients

helped with data analysis and performed the critical revisions of the manuscript. Dr Lev was the author of the original instruction and performed the critical revisions of the manuscript. Ms Yuan assisted in the manuscript drafting. Dr Hinds supervised the study design and performed critical revisions of the article. This research was supported by the Science and Technology Commission of Shanghai Municipality, China (project 12410707900). The authors have no conflicts of interest to disclose. Correspondence: Changrong Yuan, PhD, RN, School of Nursing, Second Military Medical University, 800 XiangYin Rd, Shanghai 200433, China ([email protected]). Accepted for publication February 17, 2014. DOI: 10.1097/NCC.0000000000000151

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3 factors represent an underlying higher-order factor, that of general self-care self-efficacy. Conclusions: The C-SUPPH has a valid factorial structure and can be readily applied to studying self-efficacy in Chinese patients who are diagnosed with cancers. Implications for Practice: Our findings provide support for a culturally sensitive, reliable, and valid self-efficacy measure (the C-SUPPH) of Chinese adult cancer patients’ self-care self-efficacy.

C

ancer is the leading cause of death in urban China and the second leading cause in rural China.1 The 2012 China cancer registry report indicates that the incidence and mortality of cancer have increased in China in the past 20 years. There are approximately 312 million new cases of cancer each year in China and an estimated 6 Chinese citizens are diagnosed with cancer every minute.2 Cancer survivorship is increasingly being recognized as a chronic condition, which makes quality of life (QOL) an important consideration for clinicians and researchers.3 Self-care selfefficacy has been shown to be 1 of the factors that influence the QOL and psychological well-being of cancer survivors as well as survivors of other chronic conditions.4Y9 Self-efficacy beliefs refer to people’s appraisal of a specific situation, their perception of self-management tasks, and their sense of efficacy to use their self-care skills effectively and consistently under difficult circumstances.10 Bandura11 described 3 classes of determinants in triadic reciprocal causation as behavioral, environmental, and personal factors. In most instances, the development and activation of the 3 sets of interacting factors are all highly interdependent. Thus, individuals’ behaviors, environmental offerings, and personal preferences all affect each other. Bandura noted that these factors work their mutual effects sequentially over variable courses of time. When adversities are combined with a sense of personal efficacy, paths to success are provided that can promote an individual’s personal control and resilience.12 Beliefs about coping efficacy have been shown to transform situations from threatening to safe by decreasing patients’ anxiety.12 Studies have provided evidence of a positive relationship between the level of self-efficacy and the QOL of patients with cancer.10,13,14 Thus, self-care self-efficacy indicates an individual’s confidence in his/her ability to perform relevant self-care behaviors. To maintain positive QOL and psychological well-being after the diagnosis of cancer, it is important for a patient to sustain and improve his/her self-efficacy of self-care strategies. Bandura’s social cognitive theory12 posits that the individual person simultaneously acts as an agent (acts on the environment to create change) and an object (reflects and acts on self to create change). This means that the conceptual definition of self-efficacy involves peoples’ analysis of the situation that confronts them, their consideration of alternative actions, and their judgment of their abilities to successfully carry out the actions as they act on their judgments. The operational definition of self-care self-efficacy contained within the Strategies Used by People to Promote Health (SUPPH) includes measures of an individual’s perceived confidence in carrying out self-care behaviors as well as doing the actual self-care activities. E14 n Cancer NursingTM, Vol. 38, No. 1, 2015

According to Bandura’s theory,11 self-efficacy is affected by cancer patients’ diverse cultural backgrounds (an environmental factor). Traditional Chinese culture gives great attention to health maintenance through the balance of yin and yang and keeping harmony between the spirit and physical body. A central idea is that the qi (both essential substances that make up the human body and the functions of certain body organs) is important in maintaining a healthy body. For example, some Chinese people have tried qigong (a form of exercise) as 1 strategy to combat disease and practice qigong early in the mornings because they believe that qi is stronger in the morning.15 Other traditional Chinese medicine strategies and beliefs used to help in the struggle against advanced cancer include feng shui (which involves paying attention to spatial organization) and the worship of ancestors and gods. Given the importance of self-care self-efficacy, a reliable and valid instrument of self-care self-efficacy is critical for studying and developing efficacy-enhancing interventions to improve the QOL of patients with cancer. Although a number of instruments are available for measuring self-care self-efficacy,16 instruments specific to patients with cancer are limited. According to a report of a structured review of self-efficacy measures in 2009 from Macmillan Cancer Support, the instrument Strategies Used by People to Promote Health (SUPPH) is the only scale available for assessing self-care self-efficacy in patients with cancer.17 The SUPPH, developed by Lev and Owen,18 is a self-report measure of confidence in and performance of specific self-care strategies. The 29 items of the SUPPH were initially tested in patients receiving cancer chemotherapy for any type of cancer diagnosis or with end-stage renal disease (ESRD). Validity evidence revealed that the SUPPH was positively correlated with QOL and negatively correlated with symptom distress.5,18 The instrument was further refined based on testing results and expert panel review. Moore19 noted that belief in one’s competence (self-efficacy) to perform self-care typically occurs before self-care can be attempted. Tsay and Hung20 demonstrated that the empowerment levels of patients with ESRD correlated positively with self-care self-efficacy and negatively correlated with depression. Patients with positive attitudes toward self-care selfefficacy were more likely to carry out self-care activities.20 Selfcare activities have been used to manage cancer adverse effects and have been shown to decrease stress and to control or avoid symptoms.18,21Y23 Each item of the SUPPH is rated on a 5-point scale of confidence from 1 = very little to 5 = quite a lot. The subscale scores are calculated as corresponding item mean scores, whereas the total score is the mean of all item scores. Higher scores indicate more positive perceptions of self-efficacy. Although the SUPPH

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has high internal consistency (eg, high Cronbach’s ! values), findings of its dimensionality vary by studies; as such, the factorial structure of the SUPPH needs to be further examined.17 The SUPPH dimensionality was tested by Lev and Owen18 using an exploratory factor analysis with a sample of 275 patients who were receiving either chemotherapy or hemodialysis for ESRD.18 Four factors were extracted and 81% of data variance was explained. The 4 factors were named Coping, Stress Reduction, Making Decisions, and Enjoying Life. Correlations among the factors ranged from 0.27 (between Enjoying Life and Making Decisions) to 0.56 (between Stress Reduction and Coping). Factor internal consistency estimates were high, ranging from 0.76 to 0.92.18 Lev and colleagues5,13 subsequently used factor analysis to determine the dimensionality or factorial structure of the SUPPH. Data sets from patients receiving treatment for various forms of cancer were combined for an exploratory factor analysis of the 4-factor model. Two highly related factors (coping and optimism) were combined to form ‘‘positive attitude.’’ Parsimony favored the 3-factor model. However, a 2-factor solution was reported by Lev and colleagues21 in their study with 265 prostate cancer patients (Physiological Efficacy Information and Performance Efficacy Information) that explained 81.3% of the total variance. Because of the inconsistent findings in the dimensionality/ factorial structure of the SUPPH, questions exist about the structural validity of the scale although it has been widely used in English-speaking countries as well as in nonYEnglish-speaking countries.6,23,24 However, some researchers in countries other than the United States reported that respondents had difficulty in understanding certain items.24 Testing the dimensionality and structural validity of the SUPPH in different populations is needed.17,20,25 More than a decade ago, Schwarzer and colleagues26 reported low mean levels of perceived self-efficacy in Chinese university students and suggested that the Chinese may be regarded as less individualistic than Westerners. More recently, Leung and Leung27 reported higher general self-efficacy scores among Chinese young adults (n = 695) in 28 nongovernment organizations in Hong Kong. This kind of change over time could influence a change in the underlying factor structure of a self-efficacy instrument. The purpose of the present study was to assess the factorial structure of the Chinese version of the SUPPH (C- SUPPH) in adult cancer patients in China.

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Methods

the study of Lev and Owen22 in which the SUPPH was used to measure self-care self-efficacy in 181 patients with any cancer diagnosis. Results from that study indicated that self-care selfefficacy significantly influenced patients’ QOL.22 Exclusion criteria were the presence of significant mental disease and/or cognitive impairment. A total of 970 eligible participants were invited to participate in this study. The aims of the study and the research rights were explained to each eligible participant. Upon obtaining the engaged participants’ signature on the written consent form, questionnaires were given to them by hand or by mail. Thirty-one individuals refused to participate because of a lack of interest and 175 individuals did not return the instrument. A total of 764 (79%) participants were included in the study sample.

Instruments With permission of Lev, the SUPPH was translated into Chinese using a standard procedure that included forward translation, backward translation, and cultural adaptation to develop the C-SUPPH. During the development of the C-SUPPH, the items were independently translated into Chinese by 2 Chinese bilingual oncology experts (1 with a master’s degree and the other with a doctoral degree). When discrepancies occurred in the translation, the lead author of the present study was invited to discuss and find appropriate solutions. The author of the study understood the theoretical construct of self-efficacy and sought to find meaningful adaptations rather than using literal translations of each item. Following the same procedure, 2 other oncology experts conducted the back-translation. Finally, a meeting was held with 14 clinical nurses and 5 patients with cancer to review the survey questions one by one corresponding to each of the C-SUPPH items in terms of suitability to Chinese patients with cancer. The suitability review focused on cultural sensitivity and language understanding. As a result, items of ‘‘finding ways of alleviating my stress’’ (item 3) and ‘‘using a specific technique to manage my stress’’ (item 4) were identified to have a very similar meaning in Chinese. These 2 items were therefore combined into 1 item, ‘‘finding ways to manage my stress’’; as such, the C-SUPPH includes 28 items. The same response format, a 5-point Likert scale used in the English version of the SUPPH, was used for the C-SUPPH. Factor definitions for different dimensionality solutions (eg, 2, 3, and 4 factors) derived from previous studies5,18,20 remain unchanged in the C-SUPPH. Additional information about the methods and procedure used to develop the C-SUPPH is available elsewhere.28,29

Design, Setting, and Sample From February to October 2010, a cross-sectional survey was conducted using convenience sampling in Shanghai, Jiangsu, and Shandong Provinces of China. The study was approved by the ethics committee of the Second Military Medical University. The inclusion criteria were adults (1) diagnosed with cancer, (2) 18 years or older, (3) able to be interviewed and speak Chinese mandarin, (4) at least 6 months after a diagnosis of cancer, and (5) aware of their cancer diagnosis. The decision to include patients with all types of cancer was made based on

Factorial Structure of C-SUPPH in Chinese Cancer Patients

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Methods of Data Analysis

Different factor solutions have been proposed for the SUPPH4,15,30: 2 factors (ie, Physiological Efficacy Information and Performance Efficacy Information), 3 factors (ie, Positive Attitude, Stress Reduction, and Making Decision), and 4 factors (ie, Coping, Stress Reduction, Making Decisions, and Enjoying Life). The present study systematically examined the factorial structure of the C-SUPPH by comparing alternative factor solutions. Our analytic Cancer NursingTM, Vol. 38, No. 1, 2015

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plan was to determine the dimensionality of the C-SUPPH and then examine the hierarchical factorial structure of the scale, if any. First, the above 2-, 3-, and 4-factor confirmatory factor analysis (CFA) models were fit separately with no cross-factor loadings or error covariances specified for the purpose of model fit improvement. If 3 or more factors were identified, then a second-order CFA model was applied to determine a possible higher-order factor (ie, self-care self-efficacy) that accounted for the covariance between the first-order factors.31 The model depicted in Table 1 was established based on our data in this study and shows a second-order CFA, where there are 3 firstorder factors (Positive Attitude, Stress Reduction, and Making Decision) and 1 second-order factor (self-care self-efficacy). This model examines whether and how the covariance between the 3 first-order factors could be explained by a general construct of self-care self-efficacy (SS). The merit of such a model is that it facilitates understanding of the hierarchical structure of the studied phenomena.32 Mplus7.0 statistical software was used to estimate all the CFA models.33 The multivariate normality of the C-SUPPH items was examined using Mardia multivariate skewness and kurtosis tests before modeling.34,35 The robust maximum likelihood estimator (MLR) was used to deal with nonnormality for model estimation.33 The model fit indices included the comparative fit index (CFI), the Tucker-Lewis index (TLI), root-mean-square error of approximation (RMSEA), 90% confidence interval of RMSEA, the close-fit test, and the standardized root-mean-square residual (SRMR). All the model fit indices are based on the robust versions of these model fit indices and are computed on the basis of the MLR # 2, adjusting for the effect of nonnormality. The likelihood ratio statistics used for model comparisons were computed based on the model # 2 statistics and scaling correction factors obtained with the MLR estimator. The model fit indices that widely accepted are RMSEA 0.06 or less, CFI 0.90 or greater, TLI 0.90 or greater, and SRMR 0.08 or less. Detailed information about the formulas for such calculations can be found on the Mplus Web site (http://www.statmodel.com/chidiff.shtml).

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Results

Of the 764 participants in the sample, the mean (SD) age was 54.03 (5.13) years.

Most were married (n = 645, 84.4%); gender was approximately equally distributed (women accounted for 50.8% of the sample); 34.40% (n = 263) were diagnosed with stomach or colorectal cancer; 41.9% (n = 320) had stage 2 disease; 31.0% (n = 237) received chemotherapy and surgery; and about 58.6% (n = 448) had private medical insurance. Selected results of the different CFA models are shown in Table 1. The 2-factor CFA model had the poorest fit overall with the largest model # 2 statistic (1457.41, P G .001), TLI less than 0.90, and a significant P value of close-fit test although its RMSEA (e0.06) and SRMR (e0.04) were at acceptable levels. The 3-factor CFA fit the data much better with a smaller model # 2 statistic and stronger model fit indices (CFI = 0.94, TLI = 0.94, RMSEA = 0.05 [90% confidence interval, 0.046Y0.053], and SRMR = 0.03). In addition, the close-fit test was not statistically significant (P = .565) for the 3-class model, indicating that the null hypothesis of RMSEA 0.05 or less cannot be rejected. Compared with the 3-factor model, the 4-factor model has a larger model # 2 statistic, smaller CFI and TLI, and larger RMSEA, as well as a significant close-fit test P value (P G .001), indicating that the 3-factor model fit the data better than the 4-factor model did. In addition, the likelihood ratio test (P G 0.001) also favored the 3-factor model better than the 4-factor model did (see Table 1). Based on the results of model comparisons, the 3-factor CFA model was preferred and used for the further assessment of the properties of the C-SUPPH. The descriptive statistics of the 3-dimension C-SUPPH by item, subscale, and overall selfefficacy are shown in Table 2. Similar to the findings in other studies,5,18,20 the internal consistency measured by Cronbach’s ! is high for each factor and for the overall scale, ranging from 0.83 to 0.97 for the 3 factors and 0.98 for the overall selfefficacy scale. The model-based estimates of the scale reliability32,36,37 of the 3 subscales (ie, attitude, decision making, stress reduction) as well as the overall self-efficacy scale are 0.85, 0.82, 0.85, and 0.84, respectively. The first-order CFA results show that the 3 first-order factors (eg, Positive Attitude, Stress Reduction, and Making Decisions) were highly correlated with each other (correlations ranging from 0.77 to 0.90), indicating that they likely represent something in common. We then tested a second-order CFA model based on the 3-factor solution (see Table 1). The model results of the

Table 1 & Goodness-of-Fit Indices for First-Order Confirmatory Factor Analysis (CFA) Modelsa (N = 764) Model 2 factors 3 factors 4 factors

# 2 (df, P)

SCF

CFI

TLI

RMSEA (90% CI)

Close-Fit Test P

SRMR

1457.41 (349, G.001) 999.34 (347, G.001) 1353.62 (344, G.001)

1.484 1.477 1.525

0.90 0.94 0.91

0.89 0.94 0.90

0.06 (0.061Y0.068) 0.05 (0.046Y0.053) 0.06 (0.059Y0.065)

G.001 .565 G.001

0.04 0.03 0.04

LR Test for Model Comparisons,b # 2 (df, P ) 3-factor CFA vs 2-factor CFA 3-factor CFA vs 4-factor CFA

169.66 (2, G.001) 88.13 (3, G.001)

Abbreviations: CFI, comparative fit index; CI, confidence interval; LR, likelihood ratio; RMSEA, root-mean-square error of approximation; SCF, scaling correction factor; SRMR, standardized root-mean-square residual; TLI, Tucker-Lewis index. a All models were estimated using MLR estimator and no error covariances were specified in the models. b As the robust estimator MLR was used for model estimation, the LR # 2 was computed for LR tests using the formulas described in the Mplus Web site (http://www.statmodel.com/chidiff.shtml).

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Table 2 & Descriptive Statistics of the Chinese Version of the Strategies Used by People to Promote Health by Item and Factors

Item Stress Reduction Excluding upsetting thoughts from my consciousness Using relaxation techniques to decrease my anxiety Finding ways of alleviating my stress Doing things that helped me to cope with previous emotional difficulties Practicing stress reduction techniques even when I’m feeling sick Managing to keep anxiety about illness from becoming overwhelming Thinking of myself as better off than people who became ill when they were younger than I am now Focusing on something not associated with my illness as a way of decreasing my anxiety Believing that using a technique to manage treatment stress will actually work Making Decisions Choosing among treatment alternatives recommended by my physician the one that seems right for me Making my own decision regarding treatment alternatives Deciding for myself whether or not to have treatment Positive Attitude Experiencing life’s pleasures since I became ill Doing special things for myself to make life better Convincing myself I can manage the treatment stress Helping other people going through illness and treatment Convincing myself the treatment is not so bad Keeping my stress within healthy limits Appreciating what is really important in life Believing I can find strength within myself for healing Convincing myself I’ll be OK Finding a way to help me get through this time Believing that I really have a positive attitude about my state of health Doing things that helped me to cope with previous physical difficulties Doing things to control my fatigue Finding ways of helping myself feel better if I am feeling blue Managing the side effects of treatment so that I can do things I enjoy doing Dealing with the frustration of illness and treatment Total score of self-care self-efficacy

second-order 3-factor CFA model are shown in Table 3. Whereas the items of the C-SUPPH were highly loaded onto the 3 first-order factors, the first-order factors were also highly loaded on the second-order factor (the factor loadings are 0.946, 0.822, and 0.950, respectively), and the corresponding R2 values (ie, the variance in each of the first-order factor explained by the second-order factor) were 0.894, 0.675, and 0.902, respectively (see Table 3).

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Discussion

Self-efficacy facilitates adjustment in patients with cancer and plays an important role in promoting their QOL.38 In this study, we tested the factorial structure of the C-SUPPH by comparing different factor solutions (eg, 2, 3, and 4 factors) in an adult cancer population in China. Similar to the findings of Lev and colleagues,5 our results show that the 3-factor CFA (ie, Positive Attitude, Stress Reduction, and Making Decisions) was the strongest solution. The 3-factor solution supports Bandura’s theory of self-efficacy very well. Bandura12,25,39 defined self-efficacy as

Factorial Structure of C-SUPPH in Chinese Cancer Patients

Item No.

Mean (SD)

1 2 3 4 5 6 7

26.75 (8.02) (! = 0.94) 2.87 (1.11) 3.04 (1.04) 2.97 (1.06) 2.97 (1.06) 2.96 (1.06) 2.99 (1.11) 2.98 (1.08)

8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1Y28

2.97 (1.03) 3.00 (1.06) 9.22 (2.93) (! = 0.83) 3.14 (1.08) 3.02 (1.12) 3.06 (1.18) 48.15 (15.03) (! = 0.97) 3.02 (1.15) 3.12 (1.15) 2.92 (1.13) 2.97 (1.87) 3.09 (1.09) 3.00 (1.09) 3.03 (1.08) 3.02 (1.12) 3.05 (1.16) 3.00 (1.07) 3.09 (1.11) 2.97 (1.07) 2.86 (1.08) 2.99 (1.08) 2.98 (1.12) 3.03 (1.10) 84.11 (24.47) (! = 0.98)

a person’s confidence in being able to perform relevant behaviors in a particular situation. Bandura noted that self-efficacy involved people’s beliefs in their capabilities to produce designated levels of performance and that such beliefs would influence events that can directly affect their lives. For patients with cancer, the special task of ‘‘self-care’’ refers mainly to maintaining a positive attitude or hope, reducing stress, and making appropriate decisions during the long-term procedure of treatment. A strong sense of self-efficacy in cancer patients is likely to be positively associated with patients’ behavioral efforts to perform challenging self-care tasks related to their illness by finding a way to reduce stress, making appropriate decisions related to environmental treatment offerings, and doing so within their personal attitude of expecting positive outcomes. Our results show high internal consistency estimates, and the high correlations among the 3 factors indicate a hierarchy of the factorial structure in the C-SUPPH; that is, the instrument measures 3 specific domains/factors (ie, Positive Attitude, Stress Reduction, and Making Decisions) as well as an underlying general construct of self-care self-efficacy. The latter is treated as a higher-order factor in factor analysis. The finding of the

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Table 3 & Results of Baseline Second-Order 3-Factor Confirmatory Factor Analysis Modela Item

Item No.

Excluding upsetting thoughts from my consciousness Using relaxation techniques to decrease my anxiety Finding ways of alleviating my stress Doing things that helped me to cope with previous emotional difficulties Practicing stress reduction techniques even when I’m feeling sick Managing to keep anxiety about illness from becoming overwhelming Thinking of myself as better off than people who became ill when they were younger than I am now Focusing on something not associated with my illness as a way of decreasing my anxiety Believing that using a technique to manage treatment stress will actually work Choosing among treatment alternatives recommended by my physician the one that seems right for me Making my own decision regarding treatment alternatives Deciding for myself whether or not to have treatment Experiencing life’s pleasures since I became ill Doing special things for myself to make life better Convincing myself I can manage the treatment stress Helping other people going through illness and treatment Convincing myself the treatment is not so bad Keeping my stress within healthy limits Appreciating what is really important in life Believing I can find strength within myself for healing Convincing myself I’ll be OK Finding a way to help me get through this time Believing that I really have a positive attitude about my state of health Doing things that helped me to cope with previous physical difficulties Doing things to control my fatigue Finding ways of helping myself feel better if I am feeling blue Managing the side effects of treatment so that I can do things I enjoy doing Dealing with the frustration of illness and treatment

Positive Attitude

Stress Reduction

1 2 3 4 5 6 7

0.84 0.87 0.83 0.81 0.83 0.82 0.70

8

0.80

9 10

0.82

11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Making Decisions

0.82 0.83 0.73 0.76 0.79 0.83 0.52 0.81 0.85 0.83 0.83 0.84 0.85 0.87 0.87 0.82 0.85 0.82 0.86

Self-care Self-efficacy Positive attitude Stress reduction Making decisions

0.946 0.822 0.950 Explained Variance in First-Order Factor (R2) Positive Attitude

Self-care self-efficacy Model fit

0.89

Stress Reduction 0.90 CFI = 0.94, TLI = 0.94, RMSEA = 0.05 (90% CI, 0.044Y0.051), close-fit test P = 0.853, SRMR = 0.03

Making Decisions 0.67

Close-fit test H0: RMSEA e 0.05. Abbreviations: CFI, comparative fit index; CI, confidence interval; RMSEA, root-mean-square error of approximation; SRMR, standardized root-mean-square residual; TLI, Tucker-Lewis index (also called the Bentler-Bonett nonnormed fit index). a No crossfactor loadings and error covariance were specified for the purpose of model fit improvement.

hierarchical factorial structure in the C-SUPPH is consistent with the concept of a general sense of self-care self-efficacy, which refers to confidence in a broader or general sense of personal competence across a wide range of demanding or novel situations with regard to the issue of self-care.40,41 This finding supports using the total score of the C-SUPPH as a measure of the general construct of self-care self-efficacy in conventional statistical analyses. E18 n Cancer NursingTM, Vol. 38, No. 1, 2015

Traditionally, in China, all issues related to treatment and care issues for Chinese patients were addressed by professional care providers, most especially physicians and nurses. In recent years, self-care/self-management has gradually gained support in the field of public health.42 More and more patients are encouraged to be a part of the treatment team.43,44 Orem’s selfcare theory has been introduced into the curricula design of nursing schools, and this emphasis on self-care/self-management

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has significantly changed the working model of nursing in clinical settings.45 The results of the present study provide evidence of structural validity of the C-SUPPHVa Chinese version of the well-known instrument of SUPPHVin patients with cancer in China. We believe the C-SUPPH will be helpful for care providers in China who seek to develop appropriate interventions that could promote cancer patients’ self-care self-efficacy and could ultimately improve the QOL of cancer patients in China.

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Implications for Practice

Our study demonstrated that the C-SUPPH instrument is effective in measuring self-care self-efficacy in a Chinese population. Self-efficacy has been identified as a complex issue in patients with a chronic disorder, such as cancer. However, selfefficacy is a well-established construct that has been shown to have high explanatory power and is changeable by certain interventions.12 The C-SUPPH instrument was confirmed to be a brief and precise tool for health personnel to use in their research and practice settings to assess Chinese patients with cancer. However, further examination of the validity of C-SUPPH in a larger sample is still needed. The use of specific assessments in QOL outcomes is important to detect alterations in well-being. Targeted interventions can impact patients’ psychological problems and improve the QOL.10

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Limitations

Although the findings of this study support the structural validity of the C-SUPPH in patients with cancer in China, some limitations exist. First, because of language sensitivity, 2 items (ie, item 3, ‘‘finding ways of alleviating my stress,’’ and item 4, ‘‘using a specific technique to manage my stress’’) in the original English version of SUPPH were combined into 1 item (ie, ‘‘finding ways to manage my stress’’) in the C-SUPPH. Although this is unlikely to change the factorial structure of the SUPPH, further studies are needed to replicate our findings. Second, Lev and colleagues10 pointed out that it may be most appropriate to describe self-efficacy in a homogeneous population such as people coping with the same type of cancer or other chronic illness, to understand the structure of self-efficacy beliefs in specific populations. The sample in this study included different types of cancer, and it would be interesting to see in future studies whether the C-SUPPH will show measurement invariance across different subpopulations (eg, patients with different types of cancer). Finally, the results of the present study show very high Cronbach’s ! values for the attitude subscale (0.97) and the overall self-efficacy scale (0.98). These many indicate redundancy of items and the interpretation of redundancy in the C-SUPPH. We will reexamine the ! values of the C-SUPPH scales in our future studies when applying the instrument to other populations in China. Despite the limitations, our results demonstrate the structural validity of the C-SUPPH in Chinese cancer populations.

Factorial Structure of C-SUPPH in Chinese Cancer Patients

Future research using the SUPPH in different cultures may provide further evidence of similarities as well as differences in how people in various cultures perceive their ability to care for their own health within the constraints of chronic illnesses.

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Factorial structure of a scale: Strategies Used by People to Promote Health--Chinese version.

The Strategies Used by People to Promote Health (SUPPH) is an instrument used to measure self-reported self-efficacy in patient populations. Self-effi...
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