Risk Factors and Coping Style Affect Health Outcomes in Adults With Type 2 Diabetes
Biological Research for Nursing 1-8 ª The Author(s) 2015 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1099800415569845 brn.sagepub.com
Chiung-Yu Huang, PhD, RN1, Hui-Ling Lai, PhD, RN2,3, Yung-Chuan Lu, MD4,5, Wen-Kuei Chen, PhD6, Shu-Ching Chi, MSN, RN5,7, Chu-Yun Lu, PhD, RN1, and Chun-I Chen, PhD6
Abstract Objective: Most psychosocial interventions among individuals with Type 2 diabetes mellitus (T2DM) target depressive symptoms (DSs) rather than causal antecedents that lead to DSs or affect health-related quality of life (HrQoL). This research investigated a conceptual model of the effects of risk factors and coping styles on HrQoL and DSs in patients with T2DM. Method: A descriptive, correlational design was used with a convenience sample of 241 adults with T2DM aged ≥ 20 years recruited from a hospital metabolic outpatient department. Data were collected using a demographic questionnaire, the modified Ways of Coping Checklist, the Center for Epidemiological Studies Depression Scale, the Short Form 36 Health Survey, and physiological examination. HbA1C was collected from participants’ medical records. Structural equation modeling techniques were used to analyze relationships among risk factors, mediators, and HrQoL. Results: Younger age, more education, and longer duration of diabetes predicted better physical quality of life. Duration of diabetes and three coping styles predicted DSs. Longer duration of diabetes and lower fasting glucose predicted better mental quality of life. Three coping styles acted as mediators between risk factors and health, that is, active and minimizing styles promoted positive outcomes, while avoidance promoted negative outcomes. Conclusions: This integrated model provides a holistic picture of how risk factors and coping style influence HrQoL and DSs in individuals with T2DM. Nurses could use active coping strategies in cognitive behavioral therapy to enhance glycemic control in patients with T2DM. Keywords coping, mediators, depressive symptoms, glycemic control, health-related quality of life.
Type 2 diabetes mellitus (T2DM) is a highly prevalent disease associated with long-term comorbidity that includes both physical illness and psychological effects (Luijks et al., 2012). An estimated 366.2 million adults aged 20–79 years had diabetes in 2011 and 551.9 million are predicted to have the disease by 2030; the 185.7 million increase is attributed primarily to the aging population will occur primarily in lowto middle-income countries (Whiting, Guariguata, Weil, & Shaw, 2011). In Taiwan, diabetes is the fourth leading cause of death, at a rate of 44.6 per 100,000, and 10% of the people over age 40 suffered from diabetes (Department of Health Executive Yuan, 2008). With lack of treatment or poor compliance, patients with T2DM may suffer from lower healthrelated quality of life (HrQoL), which may also increase the financial burden to society (Grandy & Fox, 2012). The annual economic cost of diabetes rose to an estimated US$245 billion in the United States from US$174 billion in 2007 (American Diabetes Association, 2012). A great part of this cost was attributable to the treatment of comorbidities, which were thought to be related to poor glycemic control and eventually
may result in complications and diminished HrQoL (Debono & Cachia, 2007; Huang, Perng, Chen, & Lai, 2008). A glycated hemoglobin (HbA1C) level of less than 7% represents good control of fasting blood sugar (Goldstein et al., 2004). Lack of blood-sugar control (higher levels of HbA1C) is associated with decreased HrQoL and increased depressive symptoms (DSs; Akinci et al., 2008; Bourdel-Marchasson et al., 2013). Higher levels of HbA1C are also associated with 1
Department of Nursing, I-Shou University, Kaohsiung, Taiwan Department of Nursing, Tzu Chi University, Hualien, Taiwan 3 Buddhist Tzu Chi General Hospital, Hualien, Taiwan 4 Department of Endocrinology, E-Da Hospital, Kaohsiung, Taiwan 5 I-Shou University, Kaohsiung, Taiwan 6 College of Management, I-Shou University, Kaohsiung, Taiwan 7 Department of Nursing, E-Da Hospital, Kaohsiung, Taiwan 2
Corresponding Author: Chiung-Yu Huang, Department of Nursing, I-Shou University, No. 8 Yida Rd, Kaohsiung 82445, Taiwan. Email: [email protected]
Downloaded from brn.sagepub.com at Bobst Library, New York University on April 20, 2015
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Biological Research for Nursing
diabetic complications, such as cardiovascular and cerebrovascular complications, neuropathy, nephropathy, and gastrointestinal problems (Tseng et al., 2012). These complications can increase disease-related stress and care burden, which are significant positive predictors of DSs (Shah, Gupchup, Borrego, Raisch, & Knapp, 2012). DSs are common in patients with T2DM, that is, in one community-based study in China about 44% of the participating patients with T2DM had experienced elevated DSs (Liu et al., 2013). In a meta-analysis, Rotella and Mannucci (2012) estimated that there was a 30% increase in the incidence of depression in diabetic adults compared to nondiabetic individuals (odds ratio ¼ 1.30, 95% confidence interval [1.11–1.53], p ¼ .001), controlling for variables such as age and gender. In a survey of diabetes care, Debono and Cachia (2007) found that more than 65% of the patients with Type I and Type II diabetes had psychological problems. However, less than 4% of these patients had received psychological treatment within the 5 years prior to the survey. Maintaining good glycemic control is an effective way of managing DSs among patients with diabetes (Chiu, Wray, Beverly, & Dominic, 2010; Nicolau, Rivera, Frances, Chacartegui, & Masmiquel, 2013). Yet most psychosocial interventions among individuals with T2DM target DSs directly rather than causal antecedents that lead to DSs or affect HrQoL. Research has revealed a number of demographic, physical, and psychosocial factors that impact health conditions and HrQoL in people with T2DM. For example, older T2DM patients had worse physical HrQoL than younger patients and women with T2DM tended to have lower HrQoL than men with the disease (Bourdel-Marchasson et al., 2013; Huang et al., 2008). Duration of diabetes can also significantly impact diabetes-related outcomes, with longer duration associated with worse health outcomes (Barnett, Ogston, McMurdo, Morris, & Evans, 2010). Psychological factors such as stressful life events, burden of diabetes symptoms, and distress may negatively affect HrQoL in people with T2DM. T2DM patients who had no complications reported better HrQoL than those who had complications (Akinci et al., 2008). Garcia (2008) reported that there was a negative correlation between number of diabetic symptoms and quality of life among T2DM patients. In a meta-analysis, Lung, Hayes, Hayen, Farmer, and Clarke (2011) reported that patients with diabetes with no complications had longer quality-adjusted life years compared to those with diabetes in general (0.81 vs. 0.76, respectively; Lung, Hayes, Hayen, Farmer, & Clarke, 2011). Research suggests that coping style might play a key role in glycemic control and overall health in patients with T2DM (Collins, Bradley, O’sullivan, & Perry, 2009). Clarke and Goosen (2009) found that coping style, especially in problem solving, was a mediator between glycemic control and DSs. In order to help patients more effectively manage diabetes, it is essential to understand the personal factors and psychosocial context associated with glycemic control and HrQoL. Patients with T2DM who have acceptable glycemic levels may have better ways of coping, which, in
turn, positively affect their HrQoL. However, to date, there remains limited knowledge about the relationship between coping style and HrQoL in patients with T2DM in Taiwan. In this study, we examined a conceptual model of the effects of risk factors and coping style on HrQoL and DSs in patients with T2DM.
Theoretical Framework Lazarus and Folkman’s (1984) model of stress, appraisal, and coping served as the conceptual framework for this study. According to this model, coping is derived from how people appraise stressors as they experience a threatening or challenging situation. The evaluation of potential stressors guides the coping response and determines the need for better coping skills (Lazarus & Folkman, 1984; Smyth & Yarandi, 1996). In the case of this study, the stressor involved is living with T2DM. Researchers have previously proposed that coping style moderates or mediates stress and health outcomes or wellbeing. Huang, Musil, Zauszniewski, and Wykle (2006) proposed a model that included three coping styles as mediators between demographic variables and health and DSs. In this study, we employ a structural equation modeling (SEM) approach to examine the specific causal antecedents of HrQoL and DSs in patients with T2DM and explore the mediation effects of coping styles between stressors associated with T2DM and health and DSs. Our purpose was to determine whether a particular coping style (active coping, minimizing coping, or avoidance coping) would better minimize the effects of T2DM-related stressors (duration of diabetes, number of complications, and glycemic control [fasting sugar and HbA1C]) on HrQoL and DSs.
Materials and Methods Design We used a cross-sectional and descriptive correlational design to examine the direct and indirect relationships among demographic variables, disease characteristics, coping style, HrQoL, and DSs among Taiwanese individuals with T2DM.
Participants We recruited a convenience sample of 241 adults (21–78 years old) with T2DM from an outpatient department in a major urban hospital in southern Taiwan. We determined sample size using Cohen and Cohen’s (1983) recommendation for correlation and regression analyses to achieve a power of .80 with a medium effect size of .15 and an a level of .05. The calculated sample size was 110 participants. To ensure accurate analysis of the SEM, we recruited 241 participants. Inclusion criteria were age above 20 years, diagnosis of T2DM for at least 6 months, absence of any other major medical conditions influencing metabolic status, and ability to communicate in Taiwanese or Chinese.
Downloaded from brn.sagepub.com at Bobst Library, New York University on April 20, 2015
Huang et al.
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Data Collection
Table 1. Participant Characteristics.
We collected demographic variables (including weight and height for calculation of body mass index [BMI]) and disease characteristics (duration of diabetes, numbers of complications of diabetes, fasting sugar, and HbA1C) using a demographic information sheet that one of the authors developed for this study. Participants’ self-reported age, gender, household monthly income reported in New Taiwan currency (NT dollar; 25,000 NT is approximately equal to US$830; categories included < 25,000, 25,001–50,000, 50,001–75,000, 75,001– 100,000, and >100,000), marital status, and education (lower than junior high school, junior high school, senior high school, and above senior high school). In addition, we acquired participants’ recent (within 3 months) HbA1C directly from the medical record. HbA1C tests served as a bio-physiological indicator of participants’ sugar-control outcome. We also acquired participants’ fasting glucose from the records. We measured coping style using modified Ways of Coping Checklist (M-WOC; Smyth & Yarandi, 1996). The original Ways of Coping checklist included 66 items. The modified checklist includes 35 items with subscales that assess for three types of coping, namely, active coping (15 items), avoidance coping (10 items), and minimizing the situation (10 items). For this checklist, active coping is defined as making efforts to change the original situation, avoidance coping is defined as wishful thinking and making efforts to escape from an unpleasant situation, and minimizing the situation is defined as making efforts to remove oneself from a stressful situation (Lazarus & Folkman, 1984). Items are rated on a 4-point Likert-type summative scale (0 ¼ does not apply, 1 ¼ used somewhat, 2 ¼ used quite a bit, and 3 ¼ used a great deal) regarding the ways the respondent coped with a wide variety of stressful situations during the previous week. The range of scores is 0–45 for the active coping subscale, 0–30 for the avoidance coping subscale, and 0–30 for the minimizing the situation subscale. A higher score indicates greater use of the specific coping style. Cronbach’s a coefficients in this study were .85, .75, and .73, respectively, for the three coping style subscales. We measured DSs with the Center for Epidemiological Studies Depression (CES-D) Scale (Radloff, 1977), a 20-item instrument designed to screen DSs in the general population. Respondents rate the frequency of specific depressive feelings and symptoms over the previous week on a 4-point Likert-type scale (0 ¼ rarely or none of the time, 1 ¼ some or little of the time, 2 ¼ occasionally or a moderate amount of time, and 3 ¼ most or all of the time). Scores range from 0 to 60; higher scores indicate more DSs. The CES-D was previously translated into Chinese and used with a sample of diabetic patients in Taiwan (Huang et al., 2007), and we used this Chineselanguage version in this study. In this study, Cronbach’s a coefficient was .89. We also administered the Short Form 36 (SF-36) Health Survey, which was developed by Ware and Sherbourne (1992) and is widely used to measure HrQoL. The construct of the SF-36 involves 36 items covering eight dimensions,
Variable Age Duration of diabetes (months) HbA1C (%) Fasting glucose (mg/dl) Gender, male Marital status Single Separated Divorced Married Education (school years) 0 ≤6
Biological Research for Nursing 1-8 ª The Author(s) 2015 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1099800415569845 brn.sagepub.com
Chiung-Yu Huang, PhD, RN1, Hui-Ling Lai, PhD, RN2,3, Yung-Chuan Lu, MD4,5, Wen-Kuei Chen, PhD6, Shu-Ching Chi, MSN, RN5,7, Chu-Yun Lu, PhD, RN1, and Chun-I Chen, PhD6
Abstract Objective: Most psychosocial interventions among individuals with Type 2 diabetes mellitus (T2DM) target depressive symptoms (DSs) rather than causal antecedents that lead to DSs or affect health-related quality of life (HrQoL). This research investigated a conceptual model of the effects of risk factors and coping styles on HrQoL and DSs in patients with T2DM. Method: A descriptive, correlational design was used with a convenience sample of 241 adults with T2DM aged ≥ 20 years recruited from a hospital metabolic outpatient department. Data were collected using a demographic questionnaire, the modified Ways of Coping Checklist, the Center for Epidemiological Studies Depression Scale, the Short Form 36 Health Survey, and physiological examination. HbA1C was collected from participants’ medical records. Structural equation modeling techniques were used to analyze relationships among risk factors, mediators, and HrQoL. Results: Younger age, more education, and longer duration of diabetes predicted better physical quality of life. Duration of diabetes and three coping styles predicted DSs. Longer duration of diabetes and lower fasting glucose predicted better mental quality of life. Three coping styles acted as mediators between risk factors and health, that is, active and minimizing styles promoted positive outcomes, while avoidance promoted negative outcomes. Conclusions: This integrated model provides a holistic picture of how risk factors and coping style influence HrQoL and DSs in individuals with T2DM. Nurses could use active coping strategies in cognitive behavioral therapy to enhance glycemic control in patients with T2DM. Keywords coping, mediators, depressive symptoms, glycemic control, health-related quality of life.
Type 2 diabetes mellitus (T2DM) is a highly prevalent disease associated with long-term comorbidity that includes both physical illness and psychological effects (Luijks et al., 2012). An estimated 366.2 million adults aged 20–79 years had diabetes in 2011 and 551.9 million are predicted to have the disease by 2030; the 185.7 million increase is attributed primarily to the aging population will occur primarily in lowto middle-income countries (Whiting, Guariguata, Weil, & Shaw, 2011). In Taiwan, diabetes is the fourth leading cause of death, at a rate of 44.6 per 100,000, and 10% of the people over age 40 suffered from diabetes (Department of Health Executive Yuan, 2008). With lack of treatment or poor compliance, patients with T2DM may suffer from lower healthrelated quality of life (HrQoL), which may also increase the financial burden to society (Grandy & Fox, 2012). The annual economic cost of diabetes rose to an estimated US$245 billion in the United States from US$174 billion in 2007 (American Diabetes Association, 2012). A great part of this cost was attributable to the treatment of comorbidities, which were thought to be related to poor glycemic control and eventually
may result in complications and diminished HrQoL (Debono & Cachia, 2007; Huang, Perng, Chen, & Lai, 2008). A glycated hemoglobin (HbA1C) level of less than 7% represents good control of fasting blood sugar (Goldstein et al., 2004). Lack of blood-sugar control (higher levels of HbA1C) is associated with decreased HrQoL and increased depressive symptoms (DSs; Akinci et al., 2008; Bourdel-Marchasson et al., 2013). Higher levels of HbA1C are also associated with 1
Department of Nursing, I-Shou University, Kaohsiung, Taiwan Department of Nursing, Tzu Chi University, Hualien, Taiwan 3 Buddhist Tzu Chi General Hospital, Hualien, Taiwan 4 Department of Endocrinology, E-Da Hospital, Kaohsiung, Taiwan 5 I-Shou University, Kaohsiung, Taiwan 6 College of Management, I-Shou University, Kaohsiung, Taiwan 7 Department of Nursing, E-Da Hospital, Kaohsiung, Taiwan 2
Corresponding Author: Chiung-Yu Huang, Department of Nursing, I-Shou University, No. 8 Yida Rd, Kaohsiung 82445, Taiwan. Email: [email protected]
Downloaded from brn.sagepub.com at Bobst Library, New York University on April 20, 2015
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Biological Research for Nursing
diabetic complications, such as cardiovascular and cerebrovascular complications, neuropathy, nephropathy, and gastrointestinal problems (Tseng et al., 2012). These complications can increase disease-related stress and care burden, which are significant positive predictors of DSs (Shah, Gupchup, Borrego, Raisch, & Knapp, 2012). DSs are common in patients with T2DM, that is, in one community-based study in China about 44% of the participating patients with T2DM had experienced elevated DSs (Liu et al., 2013). In a meta-analysis, Rotella and Mannucci (2012) estimated that there was a 30% increase in the incidence of depression in diabetic adults compared to nondiabetic individuals (odds ratio ¼ 1.30, 95% confidence interval [1.11–1.53], p ¼ .001), controlling for variables such as age and gender. In a survey of diabetes care, Debono and Cachia (2007) found that more than 65% of the patients with Type I and Type II diabetes had psychological problems. However, less than 4% of these patients had received psychological treatment within the 5 years prior to the survey. Maintaining good glycemic control is an effective way of managing DSs among patients with diabetes (Chiu, Wray, Beverly, & Dominic, 2010; Nicolau, Rivera, Frances, Chacartegui, & Masmiquel, 2013). Yet most psychosocial interventions among individuals with T2DM target DSs directly rather than causal antecedents that lead to DSs or affect HrQoL. Research has revealed a number of demographic, physical, and psychosocial factors that impact health conditions and HrQoL in people with T2DM. For example, older T2DM patients had worse physical HrQoL than younger patients and women with T2DM tended to have lower HrQoL than men with the disease (Bourdel-Marchasson et al., 2013; Huang et al., 2008). Duration of diabetes can also significantly impact diabetes-related outcomes, with longer duration associated with worse health outcomes (Barnett, Ogston, McMurdo, Morris, & Evans, 2010). Psychological factors such as stressful life events, burden of diabetes symptoms, and distress may negatively affect HrQoL in people with T2DM. T2DM patients who had no complications reported better HrQoL than those who had complications (Akinci et al., 2008). Garcia (2008) reported that there was a negative correlation between number of diabetic symptoms and quality of life among T2DM patients. In a meta-analysis, Lung, Hayes, Hayen, Farmer, and Clarke (2011) reported that patients with diabetes with no complications had longer quality-adjusted life years compared to those with diabetes in general (0.81 vs. 0.76, respectively; Lung, Hayes, Hayen, Farmer, & Clarke, 2011). Research suggests that coping style might play a key role in glycemic control and overall health in patients with T2DM (Collins, Bradley, O’sullivan, & Perry, 2009). Clarke and Goosen (2009) found that coping style, especially in problem solving, was a mediator between glycemic control and DSs. In order to help patients more effectively manage diabetes, it is essential to understand the personal factors and psychosocial context associated with glycemic control and HrQoL. Patients with T2DM who have acceptable glycemic levels may have better ways of coping, which, in
turn, positively affect their HrQoL. However, to date, there remains limited knowledge about the relationship between coping style and HrQoL in patients with T2DM in Taiwan. In this study, we examined a conceptual model of the effects of risk factors and coping style on HrQoL and DSs in patients with T2DM.
Theoretical Framework Lazarus and Folkman’s (1984) model of stress, appraisal, and coping served as the conceptual framework for this study. According to this model, coping is derived from how people appraise stressors as they experience a threatening or challenging situation. The evaluation of potential stressors guides the coping response and determines the need for better coping skills (Lazarus & Folkman, 1984; Smyth & Yarandi, 1996). In the case of this study, the stressor involved is living with T2DM. Researchers have previously proposed that coping style moderates or mediates stress and health outcomes or wellbeing. Huang, Musil, Zauszniewski, and Wykle (2006) proposed a model that included three coping styles as mediators between demographic variables and health and DSs. In this study, we employ a structural equation modeling (SEM) approach to examine the specific causal antecedents of HrQoL and DSs in patients with T2DM and explore the mediation effects of coping styles between stressors associated with T2DM and health and DSs. Our purpose was to determine whether a particular coping style (active coping, minimizing coping, or avoidance coping) would better minimize the effects of T2DM-related stressors (duration of diabetes, number of complications, and glycemic control [fasting sugar and HbA1C]) on HrQoL and DSs.
Materials and Methods Design We used a cross-sectional and descriptive correlational design to examine the direct and indirect relationships among demographic variables, disease characteristics, coping style, HrQoL, and DSs among Taiwanese individuals with T2DM.
Participants We recruited a convenience sample of 241 adults (21–78 years old) with T2DM from an outpatient department in a major urban hospital in southern Taiwan. We determined sample size using Cohen and Cohen’s (1983) recommendation for correlation and regression analyses to achieve a power of .80 with a medium effect size of .15 and an a level of .05. The calculated sample size was 110 participants. To ensure accurate analysis of the SEM, we recruited 241 participants. Inclusion criteria were age above 20 years, diagnosis of T2DM for at least 6 months, absence of any other major medical conditions influencing metabolic status, and ability to communicate in Taiwanese or Chinese.
Downloaded from brn.sagepub.com at Bobst Library, New York University on April 20, 2015
Huang et al.
3
Data Collection
Table 1. Participant Characteristics.
We collected demographic variables (including weight and height for calculation of body mass index [BMI]) and disease characteristics (duration of diabetes, numbers of complications of diabetes, fasting sugar, and HbA1C) using a demographic information sheet that one of the authors developed for this study. Participants’ self-reported age, gender, household monthly income reported in New Taiwan currency (NT dollar; 25,000 NT is approximately equal to US$830; categories included < 25,000, 25,001–50,000, 50,001–75,000, 75,001– 100,000, and >100,000), marital status, and education (lower than junior high school, junior high school, senior high school, and above senior high school). In addition, we acquired participants’ recent (within 3 months) HbA1C directly from the medical record. HbA1C tests served as a bio-physiological indicator of participants’ sugar-control outcome. We also acquired participants’ fasting glucose from the records. We measured coping style using modified Ways of Coping Checklist (M-WOC; Smyth & Yarandi, 1996). The original Ways of Coping checklist included 66 items. The modified checklist includes 35 items with subscales that assess for three types of coping, namely, active coping (15 items), avoidance coping (10 items), and minimizing the situation (10 items). For this checklist, active coping is defined as making efforts to change the original situation, avoidance coping is defined as wishful thinking and making efforts to escape from an unpleasant situation, and minimizing the situation is defined as making efforts to remove oneself from a stressful situation (Lazarus & Folkman, 1984). Items are rated on a 4-point Likert-type summative scale (0 ¼ does not apply, 1 ¼ used somewhat, 2 ¼ used quite a bit, and 3 ¼ used a great deal) regarding the ways the respondent coped with a wide variety of stressful situations during the previous week. The range of scores is 0–45 for the active coping subscale, 0–30 for the avoidance coping subscale, and 0–30 for the minimizing the situation subscale. A higher score indicates greater use of the specific coping style. Cronbach’s a coefficients in this study were .85, .75, and .73, respectively, for the three coping style subscales. We measured DSs with the Center for Epidemiological Studies Depression (CES-D) Scale (Radloff, 1977), a 20-item instrument designed to screen DSs in the general population. Respondents rate the frequency of specific depressive feelings and symptoms over the previous week on a 4-point Likert-type scale (0 ¼ rarely or none of the time, 1 ¼ some or little of the time, 2 ¼ occasionally or a moderate amount of time, and 3 ¼ most or all of the time). Scores range from 0 to 60; higher scores indicate more DSs. The CES-D was previously translated into Chinese and used with a sample of diabetic patients in Taiwan (Huang et al., 2007), and we used this Chineselanguage version in this study. In this study, Cronbach’s a coefficient was .89. We also administered the Short Form 36 (SF-36) Health Survey, which was developed by Ware and Sherbourne (1992) and is widely used to measure HrQoL. The construct of the SF-36 involves 36 items covering eight dimensions,
Variable Age Duration of diabetes (months) HbA1C (%) Fasting glucose (mg/dl) Gender, male Marital status Single Separated Divorced Married Education (school years) 0 ≤6
