Palliative and Supportive Care (2016), 14, 5 – 12. # Cambridge University Press, 2015 1478-9515/15 doi:10.1017/S1478951515000073
Influence of caregiver personality on the burden of family caregivers of terminally ill cancer patients
HA-HYUN KIM, MD, MSC,1 SEON-YOUNG KIM, MD, PHD,2,3 JAE-MIN KIM, MD, PHD,3 SUNG-WAN KIM, MD, PHD,3 IL-SEON SHIN, MD, PHD,3 HYUN-JEONG SHIM, MD, PHD,4 JUN-EUL HWANG, MD, PHD,4 IK-JOO CHUNG, MD, PHD,4 AND JIN-SANG YOON, MD, PHD3 1
Department of Psychiatry, Il Gok Yangji Hospital, Gwangju, Korea Mental Health Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea Department of Psychiatry, Chonnam National University Medical School, Gwangju, Korea 4 Department of Hemato-Oncology, Chonnam National University Medical School, Gwangju, Korea 2 3
(RECEIVED September 23, 2014; ACCEPTED December 2, 2014)
ABSTRACT Objective: To determine the influence of caregiver personality and other factors on the burden of family caregivers of terminally ill cancer patients. Method: We investigated a wide range of factors related to the patient –family caregiver dyad in a palliative care setting using a cross-sectional design. Caregiver burden was assessed using the seven-item short version of the Zarit Burden Interview (ZBI –7). Caregiver personality was assessed using the 10-item short version of the Big Five Inventory (BFI– 10), which measures the following five personality dimensions: extroversion, agreeableness, conscientiousness, neuroticism, and openness. Patient- and caregiver-related sociodemographic and psychological factors were included in the analysis because of their potential association with caregiver burden. Clinical patient data were obtained from medical charts or by using other measures. Multivariate linear regression analysis was performed to identify the independent factors associated with caregiver burden. Results: We analyzed 227 patient– family caregiver dyads. The multivariate analysis revealed that caregiver extroversion was protective against caregiver burden, whereas depressive symptoms in caregivers were related to increased burden. Neuroticism was positively correlated with caregiver burden, but this relationship was nonsignificant following adjustment for depressive symptoms. Patient-related factors were not significantly associated with caregiver burden. Significance of Results: Evaluating caregiver personality traits could facilitate identification of individuals at greater risk of high burden. Furthermore, depression screening and treatment programs for caregivers in palliative care settings are required to decrease caregiver burden. KEYWORDS: Burden, Personality, Extroversion, Depression, Palliative care
INTRODUCTION
2012). However, cancer stills remains the second leading cause of death in the majority of Organisation for Economic Co-operation and Development member nations (OECD, 2013). In addition to physical decline, terminally ill cancer patients experience such psychological stressors as depression, anxiety, interpersonal difficulties, and existential concerns (Kim, 2012). Family caregivers of terminally ill cancer patients can also experience stress and psychological problems associated with the burden of care in addition to financial
The annual incidence of cancer has risen steadily during the past decade, but the development of early detection techniques and improved treatment options have led to an increased survival rate among cancer patients (Korean Central Cancer Registry, Address correspondence and reprint requests to: Seon-Young Kim, Department of Psychiatry, Chonnam National University Medical School, Gwangju 501-757, Republic of Korea. E-Mail: [email protected]
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6 difficulties (Braun et al., 2007; Grunfeld et al., 2004). The family is a central component of palliative care, providing a tangible source of emotional support; therefore, family caregiver stress is closely related to patient distress and quality of life (Williams & McCorkle, 2011; Hodges et al., 2005). Indeed, the palliative approach refers to the family as a “unit of care” (Kristjanson & Aoun, 2004). Caregiver burden can be categorized as either objective or subjective (Jones, 1996). Subjective caregiver burden refers to such psychological factors as grief, guilt, anxiety, and depression. The degree of subjective burden experienced by caregivers is affected by patient-related factors, including the presence of multiple symptoms, decline in functional status, short projected lifespan following diagnosis, and onset of the terminal period (Grunfeld et al., 2004; Given et al., 2004). Furthermore, many caregiver characteristics can contribute to increased caregiver burden, namely: unmarried status, younger age, female sex, shorter duration of education, non-spouse or adult child status, longer time spent providing care, fewer visits from other family members, poor family functioning, low self-esteem, low monthly income, low level of social support, physical health problems, anxiety, and depression (Given et al., 2004; Grov et al., 2006; Teixeira & Pereira, 2013; Goldstein et al., 2004; Park et al., 2012; Andrews, 2001). Personality traits are key determinants of an individual’s response to different stressors and situations (Groves & Muskin, 2011). Therefore, caregiver burden in the context of terminally ill patients would be expected to be modulated by the caregiver’s personality. A previous report pertaining to personality and caregiver burden in the context of cancer patients found that self-esteem and coping strategy were significantly related (Adejumo, 2009; John & Srivastata, 1999). However, these factors do not fully encompass the various dimensions of personality. In dimensional models, the following five factors are widely accepted as the fundamental units of personality (i.e., the “Big Five” personality traits): extroversion, agreeableness, conscientiousness, neuroticism, and openness (John & Srivastata, 1999). For caregivers of patients with dementia and chronic obstructive pulmonary disease (COPD), neuroticism and extroversion are predictors of burden (Gonza´lez-Abraldes et al., 2013; Nordtug et al., 2011). However, to the best of our knowledge, only one article has been published on the influence of the Big Five personality dimensions on burden among caregivers of cancer patients at various stages of disease progression, and in that study, neuroticism was indirectly associated with caregiver burden, but only two of the Big Five dimensions (extroversion and neuroticism) were investigated (Kim et al., 2010).
Kim et al.
We aimed in the present study to determine the influence of the Big Five personality dimensions on caregiver burden in the particular context of a palliative care setting. We also investigated other factors potentially related to caregiver burden, including the sociodemographic, psychological, and clinical characteristics of the patient –family caregiver dyad, using well-validated measures.
METHODS Study Design and Recruitment Family caregivers of cancer patients admitted to the palliative care unit (PCU) of Chonnam National University Hwasun Hospital (Hwasun, South Korea) were consecutively enrolled in the main study between March of 2009 and August of 2011. The following inclusion criteria were applied: diagnosis of terminal cancer by an oncologist, estimated survival time of a few months, and admission to the PCU for palliative care. Patients admitted to the PCU prior to commencement of the study and those who were hospitalized in the PCU for less than three days were excluded. Eligible caregivers were family members (spouse, son, son-in-law, daughter, daughterin-law, parent, brother, sister, or other relative who provided direct assistance to the patient) of at least 18 years of age who served as the primary caregiver for the patient, and who completed the personality assessment questionnaires. Caregivers who were unable to understand the informed consent procedure or the study objective were excluded. In the present study, we employed the data on subjects recruited between February of 2010 and August of 2011 because investigation of the Big Five personality dimensions was begun after February of 2010, when the Korean version of the 10-item Big Five Inventory (BFI– 10) had been validated (Kim et al., 2010). Following explanation of the study’s purpose and methodology, informed consent was provided by all patients (or their familial surrogate, according to the patient’s mental status) and caregivers. The study was approved by the institutional review board at Chonnam National University Hwasun Hospital. Caregiver Burden The dependent variable, subjective caregiver burden, was measured using the seven-item short form of the Zarit Burden Interview (ZBI-7), developed specifically to assess the burden associated with palliative care (Gort et al., 2005). Overall burden was indexed by total scores on the ZBI-7, with higher scores indicating greater caregiver burden. The
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Influence of personality on caregiver burden
ZBI-7 has been validated in a Korean population (Kim et al., 2006). Caregiver Personality Caregiver personality was assessed using the 10-item short version of the BFI–10 (Rammstedt & John, 2007), which measures the Big Five dimensions of personality: extroversion (talkative, assertive, and energetic); agreeableness (good-natured, cooperative, altruistic, and empathic); conscientiousness (orderly, responsible, and dependable); neuroticism (neurotic, easily upset, and lacking in self-confidence); and openness (open to experience, intellectual, imaginative, and independent minded). Scores for each trait on the BFI– 10 range between 1 and 5. Higher scores correspond to higher levels of each personality trait (John & Srivastata, 1999). The BFI–10 has been translated into Korean and subsequently validated (Kim et al., 2010). Factors Potentially Associated with Caregiver Burden Sociodemographic, psychological, and clinical factors potentially associated with caregiver burden were the independent variables, selected on the basis of previous research (Given et al., 2004; Grov et al., 2006; Goldstein et al., 2004; Park et al., 2012; Andrews, 2001). Patients were interviewed and assessed by a psychiatrist within 4 to 7 days of admission to the PCU; family caregivers were assessed by a clinical research coordinator on the same day. The research coordinator encouraged caregivers to complete the assessment to minimize instances of incomplete data. Patient-Related Factors Data pertaining to age, sex, years of formal education, marital status, primary cancer site, time since cancer diagnosis, recurrent cancer status, current palliative radiotherapy, and detected metastasis were collected from each patient’s clinical chart. We restricted our investigation of metastasis to the two most common sites (i.e., liver and lung), because otherwise there would have been too many individual sites to include in the analysis. We used the Richmond Agitation– Sedation Scale (RASS) to determine patients’ mental status. The RASS is a 10-point scale ranging between 25 (unarousable) and 4 (combative), with a midpoint of 0 (calm). The RASS is a reliable and valid measure of level of consciousness (Sessler et al., 2002). We divided patients into the following three groups, according to RASS scores: drowsy to unarousable (21 to 25), calm (0), and restless to combative (1 to 4). Physical functioning was
measured using the Eastern Cooperative Oncology Group Performance Status (ECOG– PS) instrument, on which scores range between 0 (fully active) and 4 (completely disabled) (Oken et al., 1982). Subjective pain was measured using a numerical rating scale (NRS) ranging between 0 and 10, with higher scores indicating greater pain intensity (de Conno et al., 1994). Depressive symptoms in patients were mea˚ sberg Depression sured using the Montgomery–A ˚ sberg, Rating Scale (MADRS) (Montgomery & A 1979; Ahn et al., 2005). The MADRS is an objective 10-item questionnaire assessing symptoms experienced during the past week; scores for each item range between 1 and 6, yielding a maximum possible score of 60. Higher scores indicate more severe depressive symptoms. Caregiver-Related Factors Data regarding age, sex, years of formal education, marital status, relationship to patient, whether the caregiver had lived with the patient prior to admission, employment status, religion, medical illnesses, and caregiving situation were obtained during a face-to-face interview. The caregiver’s depressive symptoms were measured using the MADRS (Mont˚ sberg, 1979; Ahn et al., 2005). gomery & A Statistical Analysis A univariate analysis was performed on the independent variables to identify factors associated with caregiver burden. We analyzed nonnormally distributed data using the Mann –Whitney U test or the Kruskal–Wallis test for categorical variables and Spearman’s rank correlation for continuous variables. Factors significantly associated with each dependent variable in the univariate analysis ( p , 0.05) were then entered into linear regression models to identify which were associated with caregiver burden. Skewed continuous variables were normalized using log transformation. Categorical variables were entered into the model as dummy variables. A value of p , 0.05 was taken to indicate statistical significance. All statistical tests were performed using the SPSS for Windows software package (v. 13.0; SPSS Inc., Chicago). RESULTS Recruitment A total of 521 patients were admitted to the PCU during the recruitment period, of whom 370 (71.0%) satisfied the patient inclusion criteria, with 327 (88.4%) of those consenting to participate. A total of 305 caregivers for these 327 patients consented to
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8 participate; of those, 227 (74.7%) were enrolled subsequent to February of 2010, following which they completed the BFI – 10 personality questionnaire. Therefore, 227 patient – family caregiver dyads were included in the present analysis. Of the 78 patient – family caregiver dyads not included in the final analysis, a greater proportion of patients had PS scores of 0 ( p ¼ 0.046), and more caregivers answered “no” to the question of whether the caregiver lived with the patient prior to admission ( p ¼ 0.028). No significant group differences were observed for any other variable (all p . 0.05). Univariate Associations Between Patient Characteristics and Caregiver Burden The median (interquartile range [IQR]) patient age was 60 years (50 – 69 years); 133 (58.6%) of patients were male. The median (IQR) caregiver age was 51 years (41 – 63 years), of whom 52 (22.9%) were male. The median (IQR) caregiver burden score was 15 (11 – 19). In the univariate analysis, patient marital status was significantly associated with caregiver burden. No other patient characteristics were significantly associated with caregiver burden. Regarding caregiver characteristics, being a spousal caregiver and living with the patient prior to admission were associated with a higher degree of burden. Caregivers who were more extroverted reported lower burden; caregivers with higher neuroticism levels reported higher burden. Furthermore, caregiver MADRS scores were positively associated with caregiver burden. Patient and caregiver characteristics and their univariate associations with caregiver burden in the analyzed subjects are presented in Tables 1 and 2, respectively. Multivariate Linear Regression Analysis of Caregiver Burden Adjusted associations between caregiver burden and simultaneously entered independent variables were analyzed using multivariate linear regression. The analysis revealed that only caregiver extroversion and MADRS scores were significantly associated with caregiver burden. The influence of neuroticism on caregiver burden was nonsignificant following adjustment (Table 3). DISCUSSION The key finding of our present study was that caregivers’ personality and depressive symptoms were both associated with their degree of subjective burden. Patient-related factors were not significantly associated with caregiver burden following adjustment for other independent variables. To the best of our
Kim et al.
knowledge, this is the first report on the influence of the Big Five personality dimensions on degree of burden among family caregivers of cancer patients in a palliative care setting. Personality influences an individual’s response to stressful situations. Extroverts have been characterized as assertive, energetic, outgoing, sociable, talkative, and “spunky” (John & Srivastata, 1999). In stressful situations, extroverted individuals tend to choose support-seeking coping styles and to maintain optimism (Amirkhan et al., 1995). Optimism is important in reducing the burden on family caregivers (Contador et al., 2012). Social support also influences caregiver burden and mediates psychological morbidity (Teixeira & Pereira, 2013). Particularly in Asia, social support is an important factor in care burden within palliative care contexts (Wang et al., 2011). Accordingly, extroverted individuals may experience less burden because they tend to cope by seeking support and maintaining their optimism. In previous studies, extroversion and neuroticism were both predictors of burden in caregivers of dementia and COPD patients (Gonza´lez-Abraldes et al., 2013; Nordtug et al., 2011). This accords with our results, though the influence of neuroticism was attenuated following adjustment for caregiver MADRS scores. Meanwhile, in a previous investigation conducted in the United States, neuroticism, but not extroversion, was associated with burden (Kim et al., 2005). This discrepancy may result from either cultural or methodological differences; the previous study employed a small sample size, and was concerned with a homogeneous group of predominantly Caucasian spouses. Because our sample consisted entirely of Koreans, it is reasonable to suggest that cultural differences could underlie the discrepancy between these studies’ results. In a previous study, the influence of neuroticism on caregiver burden was indirect, but neuroticism directly influenced caregiver depression (Kim et al., 2005). Caregiver depression has also been reported to be directly related to caregiver burden (Grov et al., 2006). These previous reports contribute to our understanding of the relationship between neuroticism and caregiver burden, which was found not to be significant following adjustment for caregiver depression. Depression is prevalent in caregivers of patients with advanced cancer (Han et al., 2013). A previous study that employed path analysis to identify variables associated with caregiver burden reported that caregiver depression was the only variable directly and significantly associated with caregiver burden (Grov et al., 2006). In our present study, greater caregiver depression was significantly associated with higher
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Table 1. Patient-related factors and their association with caregiver burden (n ¼ 227) ZBI –7 Score
Total Sociodemographic factors Age, median (IQR) years Gender, n (%) Male Female Years of formal education, median (IQR) years Marital status, n (%) Unmarried/divorced/bereaved Married/cohabiting Clinical factors Primary cancer site, n (%) Colorectal Gastric Hepatobiliary Pancreas Head and neck Lung Others less than 5% Time since cancer diagnosis, median (IQR) years Recurred cancer, n (%) No Yes Current radiotherapy, n (%) No Yes Metastasis to liver, n (%) No Yes Metastasis to lung, n (%) No Yes RASS Score, n (%) Drowsy to unarousable (– 5 to –1) Calm (0) Restless to combative (+1 to +4) ECOG– PS, n (%) 0 1 2 3 4 Pain and psychological factors2 NRS of pain score, median (IQR) score MADRS score, median (IQR) score
Median (IQR) Score
p1
60.0 (50.0–69.0)
–
0.502 0.177
133 (58.6) 94 (41.4) 12.0 (6.0– 14.0)
16.0 (10.0–20.0) 14.0 (11.0 –18.0) –
35 (15.4) 192 (84.6)
13.0 (9.0– 18.0) 15.0 (11.0 –20.0)
46 (20.3) 40 (17.6) 36 (15.9) 32 (14.1) 21 (9.3) 13 (5.7) 39 (17.2) 13.0 (7.0– 31.0)
12.0 (9.0– 20.0) 14.5 (11.0 –17.0) 15.0 (11.3 –19.5) 16.5 (11.3 –20.8) 18.0 (11.5 –24.0) 16.0 (9.5– 18.5) 14.0 (11.0 –19.0) –
65 (28.6) 162 (71.4)
14.0 (10.0–18.5) 15.0 (11.0 –20.0)
9 (4.0) 218 (96.0)
10.0 (8.0– 17.0) 15.0 (11.0 –19.0)
138 (60.8) 89 (39.2)
15.0 (10.8–20.0) 14.0 (10.5–18.5)
183 (80.6) 44 (19.4)
15.0 (11.0 –19.0) 15.0 (10.3–20.0)
62 (27.3) 141 (62.1) 24 (10.6)
13.0 (9.8– 18.0) 15.0 (11.0 –21.0) 16.0 (10.3–19.8)
6 (2.6) 17 (7.5) 61 (26.9) 84 (37.0) 59 (26.0)
15.5 (12.0–21.0) 12.0 (8.0– 16.5) 16.0 (11.0 –20.0) 14.0 (11.0 –19.0) 15.0 (10.0–19.0)
0.084 0.034
0.118
0.817 0.411 0.099 0.409 . 0.908 0.294
0.223
2.0 (0.5– 3.0) 20.0 (13.0–26.0)
– –
0.254 0.104
ECOG –PS ¼ Eastern Cooperative Oncology Group Performance Status; IQR ¼ interquartile range; MADRS ¼ ˚ sberg Depression Rating Scale; NRS ¼ numeric rating scale; RASS ¼ Richmond Agitation –Sedation Montgomery–A Scale; ZBI – 7 ¼ seven-item short version of the Zarit Burden Interview. 1 p by Mann– Whitney U test, Kruskal –Wallis test, or Spearman’s rank correlation test, as appropriate. 2 Those factors could not be investigated on mentally incapacitated patients (n ¼ 30) to interview.
burden, consistent with earlier reports. It may be that the dysfunctional thoughts and cognitions associated with depression influence caregivers’ perceived subjective burden (Va´zquez-Sa´nchez et al., 2012). Because depression can be treated, it is important that screening and therapeutic programs be available for caregivers of patients with terminal cancer.
Our finding that patient-related factors are not associated with caregiver burden is consistent with one previous study (Park et al., 2012), although other studies have reported associations between patient health status and caregiver burden (Grunfeld et al., 2004; Given et al., 2004; Yoon et al., 2014). Methodological differences may account for these discrepancies. Our
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Table 2. Caregiver-related factors and their association with caregiver burden (n ¼ 227) ZBI –7 Score
Total
Median (IQR) Score Sociodemographic factors Age, median (IQR) years Gender, n (%) Male Female Years of formal education, median (IQR) years Marital status, n (%) Unmarried/divorced/bereaved Married/cohabiting Relation to patient, n (%) Spouse Daughter/son2 Parents Others Lived with the patient, n (%) No Yes Employment, n (%) No Yes Medical illness, n (%) No Yes Caregiving situation, n (%) Solo On a rotating basis Psychological factors Personality Extroversion, median (IQR) score Agreeableness, median (IQR) score Conscientiousness, median (IQR) score Neuroticism, median (IQR) score Openness, median (IQR) score MADRS, median (IQR) score Religion, n (%) No Yes
51.0 (41.0–63.0)
–
52 (22.9) 175 (77.1) 11.0 (5.0– 17.0)
14.0 (11.0– 19.0) 15.0 (10.0–19.0) –
36 (15.9) 191 (84.1)
15.0 (12.0–17.8) 15.0 (10.0–20.0)
124 77 10 16
(54.6) (33.9) (4.4) (7.0)
16.0 (11.3– 20.8) 13.0 (10.0–17.5) 10.5 (8.0– 18.0) 12.0 (8.5– 16.0)
56 (24.7) 171 (75.3)
12.5 (9.0– 16.0) 15.0 (11.0– 20.0)
138 (60.8) 89 (39.2)
15.0 (10.0–19.0) 15.0 (11.0– 20.0)
153 (67.4) 74 (32.6)
15.0 (11.0– 19.0) 15.0 (10.0–19.3)
119 (52.4) 108 (47.6)
16.0 (11.0– 20.0) 14.0 (10.0–18.0)
p1 0.244 0.852 0.513 0.768 0.003
,0.001 0.501 0.663 0.091
3.5 3.5 4.0 2.5 3.0 11.0
(3.0 –3.8) (3.5– 4.0) (3.5– 4.0) (2.0– 3.0) (2.5– 3.5) (5.0 –17.0)
147 (64.8) 80 (35.2)
– – – – – –
0.001 0.530 0.840 0.032 0.537 ,0.001 0.177
14.0 (10.0–19.0) 16.0 (12.0–19.0)
˚ sberg Depression Rating Scale; ZBI –7 ¼ seven-item short version IQR ¼ interquartile range; MADRS ¼ Montgomery– A of the Zarit Burden Interview. 1 p by Mann – Whitney U test, Kruskal– Wallis test, or Spearman’s rank correlation test, as appropriate. 2 Including daughter-in-law and son-in-law.
study design, which used dyads that included PCU inpatients, may have influenced the results because caregivers are probably more likely to report that patient symptoms are controlled in a PCU than in a community hospital admission (Addington-Hall & O’Callaghan, 2009). Previous studies have tended to include only a limited number of patient-related variables, such as sociodemographic factors, performance status, and cancer sites (Park et al., 2012; Yoon et al., 2014). Our study therefore represents the most comprehensive investigation of the patient–caregiver dyad-related factors independently associated with caregiver burden in a palliative care setting in Korea. We included patient sociodemographic, clinical, and
psychological variables, including depressive symptoms and mental status, in our analyses. A further strength of our study design was that the patient and caregiver data were obtained on the same day, and that the interviews were conducted independently by a psychiatrist and a research coordinator, respectively. This reduced the potential for type I errors that might result from interviewer bias. Our study has several limitations. First, the crosssectional design did not allow us to make inferences regarding causality. Therefore, further longitudinal studies are required to establish causal relationships. Second, our study sample was limited to terminally ill cancer patients in the PCU of a single hospital and
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Influence of personality on caregiver burden
Table 3. Multivariate linear regression analysis for caregiver burden (n ¼ 227) Independent Variable Patient factor Marital status Married Caregiver factor Relation to patient Spouse Daughter/son2 Parents Lived with the patient Yes MADRS Extroversion3 Neuroticism3
Regression Coefficient B
95% CI
p1
–0.33
–2.65 to 2.00
0.783
2.81 1.21 –1.24
–0.55 to 6.18 –1.69 to 4.12 –5.65 to 3.17
0.101 0.411 0.579
0.22 1.54 –9.55 2.69
–1.89 to 2.34 0.46 to 2.61 – 16.34 to –2.76 –3.61 to 8.99
0.836 0.005 0.006 0.401
˚ sberg Depression Rating Scale. CI¼confidence interval; MADRS ¼ Montgomery– A 1 Adjusted for patient marital status and caregiver factors (i.e., relation to patient, lived with patient, and MADRS and BFI–10 Extroversion and Neuroticism scores). 2 Including daughter-in-law and son-in-law. 3 Data normalized using log transformation.
their caregivers, which may limit the generalizability of our findings. Third, approximately one quarter of the enrolled dyads were excluded from the analysis because personality was not assessed. Therefore, the results may not be representative of the wider population of terminally ill cancer patients and their caregivers. Fourth, though we investigated symptoms indicative of patient distress, including mental outlook, pain, and depression, these symptoms do not encompass all of the symptoms experienced by terminally ill cancer patients. However, pain reportedly has the greatest negative impact on the well-being of terminal cancer patients (Kwon et al. 2006). In conclusion, caregiver personality traits, particularly extroversion and depressive symptoms, are independently associated with care burden. Therefore, evaluating caregiver personality traits is important to detect caregivers who may be more vulnerable to increased subjective burden. Furthermore, depression screening and treatment programs for the caregivers of terminally ill cancer patients are also required. ACKNOWLEDGMENTS This study was supported by a grant from the Korean Health Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (A120004).
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Influence of caregiver personality on the burden of family caregivers of terminally ill cancer patients
HA-HYUN KIM, MD, MSC,1 SEON-YOUNG KIM, MD, PHD,2,3 JAE-MIN KIM, MD, PHD,3 SUNG-WAN KIM, MD, PHD,3 IL-SEON SHIN, MD, PHD,3 HYUN-JEONG SHIM, MD, PHD,4 JUN-EUL HWANG, MD, PHD,4 IK-JOO CHUNG, MD, PHD,4 AND JIN-SANG YOON, MD, PHD3 1
Department of Psychiatry, Il Gok Yangji Hospital, Gwangju, Korea Mental Health Clinic, Chonnam National University Hwasun Hospital, Hwasun, Korea Department of Psychiatry, Chonnam National University Medical School, Gwangju, Korea 4 Department of Hemato-Oncology, Chonnam National University Medical School, Gwangju, Korea 2 3
(RECEIVED September 23, 2014; ACCEPTED December 2, 2014)
ABSTRACT Objective: To determine the influence of caregiver personality and other factors on the burden of family caregivers of terminally ill cancer patients. Method: We investigated a wide range of factors related to the patient –family caregiver dyad in a palliative care setting using a cross-sectional design. Caregiver burden was assessed using the seven-item short version of the Zarit Burden Interview (ZBI –7). Caregiver personality was assessed using the 10-item short version of the Big Five Inventory (BFI– 10), which measures the following five personality dimensions: extroversion, agreeableness, conscientiousness, neuroticism, and openness. Patient- and caregiver-related sociodemographic and psychological factors were included in the analysis because of their potential association with caregiver burden. Clinical patient data were obtained from medical charts or by using other measures. Multivariate linear regression analysis was performed to identify the independent factors associated with caregiver burden. Results: We analyzed 227 patient– family caregiver dyads. The multivariate analysis revealed that caregiver extroversion was protective against caregiver burden, whereas depressive symptoms in caregivers were related to increased burden. Neuroticism was positively correlated with caregiver burden, but this relationship was nonsignificant following adjustment for depressive symptoms. Patient-related factors were not significantly associated with caregiver burden. Significance of Results: Evaluating caregiver personality traits could facilitate identification of individuals at greater risk of high burden. Furthermore, depression screening and treatment programs for caregivers in palliative care settings are required to decrease caregiver burden. KEYWORDS: Burden, Personality, Extroversion, Depression, Palliative care
INTRODUCTION
2012). However, cancer stills remains the second leading cause of death in the majority of Organisation for Economic Co-operation and Development member nations (OECD, 2013). In addition to physical decline, terminally ill cancer patients experience such psychological stressors as depression, anxiety, interpersonal difficulties, and existential concerns (Kim, 2012). Family caregivers of terminally ill cancer patients can also experience stress and psychological problems associated with the burden of care in addition to financial
The annual incidence of cancer has risen steadily during the past decade, but the development of early detection techniques and improved treatment options have led to an increased survival rate among cancer patients (Korean Central Cancer Registry, Address correspondence and reprint requests to: Seon-Young Kim, Department of Psychiatry, Chonnam National University Medical School, Gwangju 501-757, Republic of Korea. E-Mail: [email protected]
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6 difficulties (Braun et al., 2007; Grunfeld et al., 2004). The family is a central component of palliative care, providing a tangible source of emotional support; therefore, family caregiver stress is closely related to patient distress and quality of life (Williams & McCorkle, 2011; Hodges et al., 2005). Indeed, the palliative approach refers to the family as a “unit of care” (Kristjanson & Aoun, 2004). Caregiver burden can be categorized as either objective or subjective (Jones, 1996). Subjective caregiver burden refers to such psychological factors as grief, guilt, anxiety, and depression. The degree of subjective burden experienced by caregivers is affected by patient-related factors, including the presence of multiple symptoms, decline in functional status, short projected lifespan following diagnosis, and onset of the terminal period (Grunfeld et al., 2004; Given et al., 2004). Furthermore, many caregiver characteristics can contribute to increased caregiver burden, namely: unmarried status, younger age, female sex, shorter duration of education, non-spouse or adult child status, longer time spent providing care, fewer visits from other family members, poor family functioning, low self-esteem, low monthly income, low level of social support, physical health problems, anxiety, and depression (Given et al., 2004; Grov et al., 2006; Teixeira & Pereira, 2013; Goldstein et al., 2004; Park et al., 2012; Andrews, 2001). Personality traits are key determinants of an individual’s response to different stressors and situations (Groves & Muskin, 2011). Therefore, caregiver burden in the context of terminally ill patients would be expected to be modulated by the caregiver’s personality. A previous report pertaining to personality and caregiver burden in the context of cancer patients found that self-esteem and coping strategy were significantly related (Adejumo, 2009; John & Srivastata, 1999). However, these factors do not fully encompass the various dimensions of personality. In dimensional models, the following five factors are widely accepted as the fundamental units of personality (i.e., the “Big Five” personality traits): extroversion, agreeableness, conscientiousness, neuroticism, and openness (John & Srivastata, 1999). For caregivers of patients with dementia and chronic obstructive pulmonary disease (COPD), neuroticism and extroversion are predictors of burden (Gonza´lez-Abraldes et al., 2013; Nordtug et al., 2011). However, to the best of our knowledge, only one article has been published on the influence of the Big Five personality dimensions on burden among caregivers of cancer patients at various stages of disease progression, and in that study, neuroticism was indirectly associated with caregiver burden, but only two of the Big Five dimensions (extroversion and neuroticism) were investigated (Kim et al., 2010).
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We aimed in the present study to determine the influence of the Big Five personality dimensions on caregiver burden in the particular context of a palliative care setting. We also investigated other factors potentially related to caregiver burden, including the sociodemographic, psychological, and clinical characteristics of the patient –family caregiver dyad, using well-validated measures.
METHODS Study Design and Recruitment Family caregivers of cancer patients admitted to the palliative care unit (PCU) of Chonnam National University Hwasun Hospital (Hwasun, South Korea) were consecutively enrolled in the main study between March of 2009 and August of 2011. The following inclusion criteria were applied: diagnosis of terminal cancer by an oncologist, estimated survival time of a few months, and admission to the PCU for palliative care. Patients admitted to the PCU prior to commencement of the study and those who were hospitalized in the PCU for less than three days were excluded. Eligible caregivers were family members (spouse, son, son-in-law, daughter, daughterin-law, parent, brother, sister, or other relative who provided direct assistance to the patient) of at least 18 years of age who served as the primary caregiver for the patient, and who completed the personality assessment questionnaires. Caregivers who were unable to understand the informed consent procedure or the study objective were excluded. In the present study, we employed the data on subjects recruited between February of 2010 and August of 2011 because investigation of the Big Five personality dimensions was begun after February of 2010, when the Korean version of the 10-item Big Five Inventory (BFI– 10) had been validated (Kim et al., 2010). Following explanation of the study’s purpose and methodology, informed consent was provided by all patients (or their familial surrogate, according to the patient’s mental status) and caregivers. The study was approved by the institutional review board at Chonnam National University Hwasun Hospital. Caregiver Burden The dependent variable, subjective caregiver burden, was measured using the seven-item short form of the Zarit Burden Interview (ZBI-7), developed specifically to assess the burden associated with palliative care (Gort et al., 2005). Overall burden was indexed by total scores on the ZBI-7, with higher scores indicating greater caregiver burden. The
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ZBI-7 has been validated in a Korean population (Kim et al., 2006). Caregiver Personality Caregiver personality was assessed using the 10-item short version of the BFI–10 (Rammstedt & John, 2007), which measures the Big Five dimensions of personality: extroversion (talkative, assertive, and energetic); agreeableness (good-natured, cooperative, altruistic, and empathic); conscientiousness (orderly, responsible, and dependable); neuroticism (neurotic, easily upset, and lacking in self-confidence); and openness (open to experience, intellectual, imaginative, and independent minded). Scores for each trait on the BFI– 10 range between 1 and 5. Higher scores correspond to higher levels of each personality trait (John & Srivastata, 1999). The BFI–10 has been translated into Korean and subsequently validated (Kim et al., 2010). Factors Potentially Associated with Caregiver Burden Sociodemographic, psychological, and clinical factors potentially associated with caregiver burden were the independent variables, selected on the basis of previous research (Given et al., 2004; Grov et al., 2006; Goldstein et al., 2004; Park et al., 2012; Andrews, 2001). Patients were interviewed and assessed by a psychiatrist within 4 to 7 days of admission to the PCU; family caregivers were assessed by a clinical research coordinator on the same day. The research coordinator encouraged caregivers to complete the assessment to minimize instances of incomplete data. Patient-Related Factors Data pertaining to age, sex, years of formal education, marital status, primary cancer site, time since cancer diagnosis, recurrent cancer status, current palliative radiotherapy, and detected metastasis were collected from each patient’s clinical chart. We restricted our investigation of metastasis to the two most common sites (i.e., liver and lung), because otherwise there would have been too many individual sites to include in the analysis. We used the Richmond Agitation– Sedation Scale (RASS) to determine patients’ mental status. The RASS is a 10-point scale ranging between 25 (unarousable) and 4 (combative), with a midpoint of 0 (calm). The RASS is a reliable and valid measure of level of consciousness (Sessler et al., 2002). We divided patients into the following three groups, according to RASS scores: drowsy to unarousable (21 to 25), calm (0), and restless to combative (1 to 4). Physical functioning was
measured using the Eastern Cooperative Oncology Group Performance Status (ECOG– PS) instrument, on which scores range between 0 (fully active) and 4 (completely disabled) (Oken et al., 1982). Subjective pain was measured using a numerical rating scale (NRS) ranging between 0 and 10, with higher scores indicating greater pain intensity (de Conno et al., 1994). Depressive symptoms in patients were mea˚ sberg Depression sured using the Montgomery–A ˚ sberg, Rating Scale (MADRS) (Montgomery & A 1979; Ahn et al., 2005). The MADRS is an objective 10-item questionnaire assessing symptoms experienced during the past week; scores for each item range between 1 and 6, yielding a maximum possible score of 60. Higher scores indicate more severe depressive symptoms. Caregiver-Related Factors Data regarding age, sex, years of formal education, marital status, relationship to patient, whether the caregiver had lived with the patient prior to admission, employment status, religion, medical illnesses, and caregiving situation were obtained during a face-to-face interview. The caregiver’s depressive symptoms were measured using the MADRS (Mont˚ sberg, 1979; Ahn et al., 2005). gomery & A Statistical Analysis A univariate analysis was performed on the independent variables to identify factors associated with caregiver burden. We analyzed nonnormally distributed data using the Mann –Whitney U test or the Kruskal–Wallis test for categorical variables and Spearman’s rank correlation for continuous variables. Factors significantly associated with each dependent variable in the univariate analysis ( p , 0.05) were then entered into linear regression models to identify which were associated with caregiver burden. Skewed continuous variables were normalized using log transformation. Categorical variables were entered into the model as dummy variables. A value of p , 0.05 was taken to indicate statistical significance. All statistical tests were performed using the SPSS for Windows software package (v. 13.0; SPSS Inc., Chicago). RESULTS Recruitment A total of 521 patients were admitted to the PCU during the recruitment period, of whom 370 (71.0%) satisfied the patient inclusion criteria, with 327 (88.4%) of those consenting to participate. A total of 305 caregivers for these 327 patients consented to
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8 participate; of those, 227 (74.7%) were enrolled subsequent to February of 2010, following which they completed the BFI – 10 personality questionnaire. Therefore, 227 patient – family caregiver dyads were included in the present analysis. Of the 78 patient – family caregiver dyads not included in the final analysis, a greater proportion of patients had PS scores of 0 ( p ¼ 0.046), and more caregivers answered “no” to the question of whether the caregiver lived with the patient prior to admission ( p ¼ 0.028). No significant group differences were observed for any other variable (all p . 0.05). Univariate Associations Between Patient Characteristics and Caregiver Burden The median (interquartile range [IQR]) patient age was 60 years (50 – 69 years); 133 (58.6%) of patients were male. The median (IQR) caregiver age was 51 years (41 – 63 years), of whom 52 (22.9%) were male. The median (IQR) caregiver burden score was 15 (11 – 19). In the univariate analysis, patient marital status was significantly associated with caregiver burden. No other patient characteristics were significantly associated with caregiver burden. Regarding caregiver characteristics, being a spousal caregiver and living with the patient prior to admission were associated with a higher degree of burden. Caregivers who were more extroverted reported lower burden; caregivers with higher neuroticism levels reported higher burden. Furthermore, caregiver MADRS scores were positively associated with caregiver burden. Patient and caregiver characteristics and their univariate associations with caregiver burden in the analyzed subjects are presented in Tables 1 and 2, respectively. Multivariate Linear Regression Analysis of Caregiver Burden Adjusted associations between caregiver burden and simultaneously entered independent variables were analyzed using multivariate linear regression. The analysis revealed that only caregiver extroversion and MADRS scores were significantly associated with caregiver burden. The influence of neuroticism on caregiver burden was nonsignificant following adjustment (Table 3). DISCUSSION The key finding of our present study was that caregivers’ personality and depressive symptoms were both associated with their degree of subjective burden. Patient-related factors were not significantly associated with caregiver burden following adjustment for other independent variables. To the best of our
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knowledge, this is the first report on the influence of the Big Five personality dimensions on degree of burden among family caregivers of cancer patients in a palliative care setting. Personality influences an individual’s response to stressful situations. Extroverts have been characterized as assertive, energetic, outgoing, sociable, talkative, and “spunky” (John & Srivastata, 1999). In stressful situations, extroverted individuals tend to choose support-seeking coping styles and to maintain optimism (Amirkhan et al., 1995). Optimism is important in reducing the burden on family caregivers (Contador et al., 2012). Social support also influences caregiver burden and mediates psychological morbidity (Teixeira & Pereira, 2013). Particularly in Asia, social support is an important factor in care burden within palliative care contexts (Wang et al., 2011). Accordingly, extroverted individuals may experience less burden because they tend to cope by seeking support and maintaining their optimism. In previous studies, extroversion and neuroticism were both predictors of burden in caregivers of dementia and COPD patients (Gonza´lez-Abraldes et al., 2013; Nordtug et al., 2011). This accords with our results, though the influence of neuroticism was attenuated following adjustment for caregiver MADRS scores. Meanwhile, in a previous investigation conducted in the United States, neuroticism, but not extroversion, was associated with burden (Kim et al., 2005). This discrepancy may result from either cultural or methodological differences; the previous study employed a small sample size, and was concerned with a homogeneous group of predominantly Caucasian spouses. Because our sample consisted entirely of Koreans, it is reasonable to suggest that cultural differences could underlie the discrepancy between these studies’ results. In a previous study, the influence of neuroticism on caregiver burden was indirect, but neuroticism directly influenced caregiver depression (Kim et al., 2005). Caregiver depression has also been reported to be directly related to caregiver burden (Grov et al., 2006). These previous reports contribute to our understanding of the relationship between neuroticism and caregiver burden, which was found not to be significant following adjustment for caregiver depression. Depression is prevalent in caregivers of patients with advanced cancer (Han et al., 2013). A previous study that employed path analysis to identify variables associated with caregiver burden reported that caregiver depression was the only variable directly and significantly associated with caregiver burden (Grov et al., 2006). In our present study, greater caregiver depression was significantly associated with higher
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Table 1. Patient-related factors and their association with caregiver burden (n ¼ 227) ZBI –7 Score
Total Sociodemographic factors Age, median (IQR) years Gender, n (%) Male Female Years of formal education, median (IQR) years Marital status, n (%) Unmarried/divorced/bereaved Married/cohabiting Clinical factors Primary cancer site, n (%) Colorectal Gastric Hepatobiliary Pancreas Head and neck Lung Others less than 5% Time since cancer diagnosis, median (IQR) years Recurred cancer, n (%) No Yes Current radiotherapy, n (%) No Yes Metastasis to liver, n (%) No Yes Metastasis to lung, n (%) No Yes RASS Score, n (%) Drowsy to unarousable (– 5 to –1) Calm (0) Restless to combative (+1 to +4) ECOG– PS, n (%) 0 1 2 3 4 Pain and psychological factors2 NRS of pain score, median (IQR) score MADRS score, median (IQR) score
Median (IQR) Score
p1
60.0 (50.0–69.0)
–
0.502 0.177
133 (58.6) 94 (41.4) 12.0 (6.0– 14.0)
16.0 (10.0–20.0) 14.0 (11.0 –18.0) –
35 (15.4) 192 (84.6)
13.0 (9.0– 18.0) 15.0 (11.0 –20.0)
46 (20.3) 40 (17.6) 36 (15.9) 32 (14.1) 21 (9.3) 13 (5.7) 39 (17.2) 13.0 (7.0– 31.0)
12.0 (9.0– 20.0) 14.5 (11.0 –17.0) 15.0 (11.3 –19.5) 16.5 (11.3 –20.8) 18.0 (11.5 –24.0) 16.0 (9.5– 18.5) 14.0 (11.0 –19.0) –
65 (28.6) 162 (71.4)
14.0 (10.0–18.5) 15.0 (11.0 –20.0)
9 (4.0) 218 (96.0)
10.0 (8.0– 17.0) 15.0 (11.0 –19.0)
138 (60.8) 89 (39.2)
15.0 (10.8–20.0) 14.0 (10.5–18.5)
183 (80.6) 44 (19.4)
15.0 (11.0 –19.0) 15.0 (10.3–20.0)
62 (27.3) 141 (62.1) 24 (10.6)
13.0 (9.8– 18.0) 15.0 (11.0 –21.0) 16.0 (10.3–19.8)
6 (2.6) 17 (7.5) 61 (26.9) 84 (37.0) 59 (26.0)
15.5 (12.0–21.0) 12.0 (8.0– 16.5) 16.0 (11.0 –20.0) 14.0 (11.0 –19.0) 15.0 (10.0–19.0)
0.084 0.034
0.118
0.817 0.411 0.099 0.409 . 0.908 0.294
0.223
2.0 (0.5– 3.0) 20.0 (13.0–26.0)
– –
0.254 0.104
ECOG –PS ¼ Eastern Cooperative Oncology Group Performance Status; IQR ¼ interquartile range; MADRS ¼ ˚ sberg Depression Rating Scale; NRS ¼ numeric rating scale; RASS ¼ Richmond Agitation –Sedation Montgomery–A Scale; ZBI – 7 ¼ seven-item short version of the Zarit Burden Interview. 1 p by Mann– Whitney U test, Kruskal –Wallis test, or Spearman’s rank correlation test, as appropriate. 2 Those factors could not be investigated on mentally incapacitated patients (n ¼ 30) to interview.
burden, consistent with earlier reports. It may be that the dysfunctional thoughts and cognitions associated with depression influence caregivers’ perceived subjective burden (Va´zquez-Sa´nchez et al., 2012). Because depression can be treated, it is important that screening and therapeutic programs be available for caregivers of patients with terminal cancer.
Our finding that patient-related factors are not associated with caregiver burden is consistent with one previous study (Park et al., 2012), although other studies have reported associations between patient health status and caregiver burden (Grunfeld et al., 2004; Given et al., 2004; Yoon et al., 2014). Methodological differences may account for these discrepancies. Our
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Table 2. Caregiver-related factors and their association with caregiver burden (n ¼ 227) ZBI –7 Score
Total
Median (IQR) Score Sociodemographic factors Age, median (IQR) years Gender, n (%) Male Female Years of formal education, median (IQR) years Marital status, n (%) Unmarried/divorced/bereaved Married/cohabiting Relation to patient, n (%) Spouse Daughter/son2 Parents Others Lived with the patient, n (%) No Yes Employment, n (%) No Yes Medical illness, n (%) No Yes Caregiving situation, n (%) Solo On a rotating basis Psychological factors Personality Extroversion, median (IQR) score Agreeableness, median (IQR) score Conscientiousness, median (IQR) score Neuroticism, median (IQR) score Openness, median (IQR) score MADRS, median (IQR) score Religion, n (%) No Yes
51.0 (41.0–63.0)
–
52 (22.9) 175 (77.1) 11.0 (5.0– 17.0)
14.0 (11.0– 19.0) 15.0 (10.0–19.0) –
36 (15.9) 191 (84.1)
15.0 (12.0–17.8) 15.0 (10.0–20.0)
124 77 10 16
(54.6) (33.9) (4.4) (7.0)
16.0 (11.3– 20.8) 13.0 (10.0–17.5) 10.5 (8.0– 18.0) 12.0 (8.5– 16.0)
56 (24.7) 171 (75.3)
12.5 (9.0– 16.0) 15.0 (11.0– 20.0)
138 (60.8) 89 (39.2)
15.0 (10.0–19.0) 15.0 (11.0– 20.0)
153 (67.4) 74 (32.6)
15.0 (11.0– 19.0) 15.0 (10.0–19.3)
119 (52.4) 108 (47.6)
16.0 (11.0– 20.0) 14.0 (10.0–18.0)
p1 0.244 0.852 0.513 0.768 0.003
,0.001 0.501 0.663 0.091
3.5 3.5 4.0 2.5 3.0 11.0
(3.0 –3.8) (3.5– 4.0) (3.5– 4.0) (2.0– 3.0) (2.5– 3.5) (5.0 –17.0)
147 (64.8) 80 (35.2)
– – – – – –
0.001 0.530 0.840 0.032 0.537 ,0.001 0.177
14.0 (10.0–19.0) 16.0 (12.0–19.0)
˚ sberg Depression Rating Scale; ZBI –7 ¼ seven-item short version IQR ¼ interquartile range; MADRS ¼ Montgomery– A of the Zarit Burden Interview. 1 p by Mann – Whitney U test, Kruskal– Wallis test, or Spearman’s rank correlation test, as appropriate. 2 Including daughter-in-law and son-in-law.
study design, which used dyads that included PCU inpatients, may have influenced the results because caregivers are probably more likely to report that patient symptoms are controlled in a PCU than in a community hospital admission (Addington-Hall & O’Callaghan, 2009). Previous studies have tended to include only a limited number of patient-related variables, such as sociodemographic factors, performance status, and cancer sites (Park et al., 2012; Yoon et al., 2014). Our study therefore represents the most comprehensive investigation of the patient–caregiver dyad-related factors independently associated with caregiver burden in a palliative care setting in Korea. We included patient sociodemographic, clinical, and
psychological variables, including depressive symptoms and mental status, in our analyses. A further strength of our study design was that the patient and caregiver data were obtained on the same day, and that the interviews were conducted independently by a psychiatrist and a research coordinator, respectively. This reduced the potential for type I errors that might result from interviewer bias. Our study has several limitations. First, the crosssectional design did not allow us to make inferences regarding causality. Therefore, further longitudinal studies are required to establish causal relationships. Second, our study sample was limited to terminally ill cancer patients in the PCU of a single hospital and
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11
Influence of personality on caregiver burden
Table 3. Multivariate linear regression analysis for caregiver burden (n ¼ 227) Independent Variable Patient factor Marital status Married Caregiver factor Relation to patient Spouse Daughter/son2 Parents Lived with the patient Yes MADRS Extroversion3 Neuroticism3
Regression Coefficient B
95% CI
p1
–0.33
–2.65 to 2.00
0.783
2.81 1.21 –1.24
–0.55 to 6.18 –1.69 to 4.12 –5.65 to 3.17
0.101 0.411 0.579
0.22 1.54 –9.55 2.69
–1.89 to 2.34 0.46 to 2.61 – 16.34 to –2.76 –3.61 to 8.99
0.836 0.005 0.006 0.401
˚ sberg Depression Rating Scale. CI¼confidence interval; MADRS ¼ Montgomery– A 1 Adjusted for patient marital status and caregiver factors (i.e., relation to patient, lived with patient, and MADRS and BFI–10 Extroversion and Neuroticism scores). 2 Including daughter-in-law and son-in-law. 3 Data normalized using log transformation.
their caregivers, which may limit the generalizability of our findings. Third, approximately one quarter of the enrolled dyads were excluded from the analysis because personality was not assessed. Therefore, the results may not be representative of the wider population of terminally ill cancer patients and their caregivers. Fourth, though we investigated symptoms indicative of patient distress, including mental outlook, pain, and depression, these symptoms do not encompass all of the symptoms experienced by terminally ill cancer patients. However, pain reportedly has the greatest negative impact on the well-being of terminal cancer patients (Kwon et al. 2006). In conclusion, caregiver personality traits, particularly extroversion and depressive symptoms, are independently associated with care burden. Therefore, evaluating caregiver personality traits is important to detect caregivers who may be more vulnerable to increased subjective burden. Furthermore, depression screening and treatment programs for the caregivers of terminally ill cancer patients are also required. ACKNOWLEDGMENTS This study was supported by a grant from the Korean Health Technology R&D Project, Ministry of Health and Welfare, Republic of Korea (A120004).
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