Download Prevalence of severe depressive symptoms increases as

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DOI 10.1007/s00520-015-2747-0
ORIGINAL ARTICLE
Prevalence of severe depressive symptoms increases
as death approaches and is associated with disease burden,
tangible social support, and high self-perceived burden to others
Siew Tzuh Tang 1 & Jen-Shi Chen 2 & Wen-Chi Chou 3 & Kuan-Chia Lin 4 &
Wen-Cheng Chang 2 & Chia-Hsun Hsieh 3 & Chiao-En Wu 3
Received: 9 November 2014 / Accepted: 22 April 2015
# Springer-Verlag Berlin Heidelberg 2015
Abstract
Purpose Terminally ill cancer patients experience progressive
functional decline, accelerating symptom severity, deteriorating social support, and self-perceived burden to others (SPB),
predisposing them to depressive symptoms. However, changes in the prevalence of severe depressive symptoms as death
approaches and the unique roles of these four variables have
not been adequately studied. This study explored longitudinal
changes in and associations of symptom distress, functional
dependence, social support, and SPB with prevalence of severe depressive symptoms in the last year of life.
Methods A convenience sample of 325 cancer patients was
longitudinally followed until death. Prevalence of severe depressive symptoms (score ≥11 on the depression subscale of
the Hospital Anxiety and Depression Scale) was examined by
multivariate logistic regression modeling with the generalized
estimating equation.
Results The prevalence of severe depressive symptoms
increased as death approached. The likelihood of severe
depressive symptoms was significantly higher in patients
who had higher levels of symptom distress and functional dependence, received greater tangible support, and reported high SPB, but lower for patients reporting a
higher level of affectionate support and positive social
interactions with their supportive network.
Conclusion Prevalence of severe depressive symptoms increased as death approached and was associated with several modifiable factors. Healthcare professionals should
become familiar with these factors to identify vulnerable
patients. To decrease the likelihood of terminally ill cancer patients’ severe depressive symptoms, they should receive effective interventions to manage their symptoms,
appropriately foster social support to restore their fragile
self-esteem due to depending on others, and lighten their
SPB.
Keywords Clinical depression . Depressive symptoms .
Sense of burden to others . Symptom distress . Functional
dependence . Social support . End-of-life care
* Siew Tzuh Tang
[email protected]
Jen-Shi Chen
[email protected]
Wen-Chi Chou
[email protected]
Chiao-En Wu
[email protected]
1
School of Nursing, Chang Gung University, 259 Wen-Hwa 1st Road,
Kwei-Shan, Tao-Yuan 333, Taiwan
2
Division of Hematology-Oncology, Chang Gung Memorial Hospital
at Linkou, Chang Gung University College of Medicine,
Tao-Yuan, Taiwan
3
Division of Hematology-Oncology, Chang Gung Memorial Hospital
at Linkou, Tao-Yuan, Taiwan
4
Department of Health Care and Management, National Taipei
University of Nursing and Health Science, Taipei, Taiwan
Kuan-Chia Lin
[email protected]
Wen-Cheng Chang
[email protected]
Chia-Hsun Hsieh
[email protected]
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Introduction
Terminally ill cancer patients are subjected to multiple,
intertwined physical, psychological, and social stressors that
contribute to the likelihood of suffering emotional distress
over the dying process. One of the most common mental
health problems for terminally ill cancer patients is depression
[1–3] leading to emotional suffering and diminished quality of
life (QOL) [4]. Furthermore, depression may interfere with
patients’ ability to cope with cancer, hinder adherence to cancer treatment [5], extend hospitalization, exaggerate
healthcare expenditures [5], trigger suicidal ideation [6] and
suicide [7], and increase cancer mortality [8]. However, longitudinal changes in the prevalence of severe depressive
symptoms for cancer patients at the end of life (EOL) are
under-investigated and poorly understood [1–3]. Among the
four longitudinal studies [9–12] of changes in the prevalence
of severe depressive symptoms over the dying process, many
were underpowered by small samples (N=4510 and 5811) or
biased by high attrition [9–11] with a lengthy interval between
the last interview and patient death (13±11 months) [12].
Furthermore, depression is frequently overlooked [1, 3],
despite being recognized as an important [1–3], potentially
fatal [8], and treatable [13] complication of cancer.
Emotionally distressed terminally ill cancer patients should
be identified as potential targets for tailored interventions to
maximize their psychological well-being. The strongest predictor of depression in cancer patients is disease burden [6,
14]. As death approaches, unavoidable functional decline [11,
12, 15], and accelerating symptom severity [12, 15] may predispose dying patients to depend heavily on their family caregivers for assistance with every aspect of daily living.
Although adequate social support is recognized as a valuable
resource for buffering stress and loss [16], dying cancer patients may have a more complex reaction. Those who receive
care may feel that they are creating physical, emotional, social,
and economic hardships on their family without opportunities
to restore the balance between receiving and giving help,
thereby increasing self-perceived burden to others (SPB)
[17, 18] and precipitating depressive mood [17–20].
However, the unique roles of disease burden, social support, and SPB in determining cancer patients’ likelihood of
clinical depression have never been evaluated together.
Furthermore, the association of SPB with terminally ill cancer
patients’ depressive symptoms over their dying process has
never been longitudinally evaluated, despite these patients’
functional decline and symptom severity accelerating as death
approaches. Filling these gaps in knowledge may inform interventions to alleviate these patients’ suffering and improve
QOL as death approaches. Therefore, the purposes of this
longitudinal study were to explore changes in and associations
of disease burden (symptom distress and functional dependence), social support, and SPB with the prevalence of severe
depressive symptoms in terminally ill cancer patients over
their dying process. We hypothesized that the prevalence of
severe depressive symptoms would increase as patients
approached EOL in response to growing disease burden, deteriorating social support, and accelerating SPB.
Methods
Study design and sample
This longitudinal study extends an earlier study of factors
influencing QOL in Taiwanese terminally ill cancer patients
over their dying process [21] by following them up for another
6 months (through December 2013). Detailed study methods
have been published [21]. A convenience sample of cancer
patients was recruited from the medical inpatient units of a
medical center in northwest Taiwan. Eligibility criteria included the following: (1) diagnosed with a terminal stage disease
judged by their oncologists as unresponsive to curative cancer
treatment and continuing to progress, (2) cognitively competent as evaluated by their primary physician’s clinical assessment and ability to communicate coherently with data collectors, and (3) ≥20 years old.
Procedures
Participants were referred by their primary physician to data
collectors when terminal status was first recognized, but patients were not necessarily informed or aware of their diagnosis and prognosis. Data collectors were trained, experienced
oncology nurses who explained the study to patients and invited them to participate. Patients who agreed to participate
were interviewed in person while hospitalized or waiting for
outpatient visits and approximately every 2 weeks thereafter
until they declined to participate or died. Depressive symptoms, disease burden, social support, and SPB were assessed
at every data collection interview, whereas demographics and
disease characteristics were measured at baseline (enrollment)
only. Patients who did not return to hospital were interviewed
by telephone. The study site’s research ethics committee approved the research protocol. All subjects provided written
informed consent.
Outcome variable
Depressive symptoms were measured by the 7-item depression subscale of the Hospital Anxiety and Depression Scale
(HADS) [22], the most widely used tool for assessing psychological morbidity in cancer patients under palliative care [23].
The HADS is not recognized as a diagnostic instrument but is
suitable as a screening tool [24]. The depression subscale
(HADS-D) assesses psychological and cognitive symptoms
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rather than physiological symptoms, thus avoiding confounding measures that may overestimate the severity of depression
for cancer patients who commonly suffer from multiple physical symptoms. Total scores on the HADS-D range from 0 to
21; higher scores indicate greater depression. Patients with
HAD-D scores ≤7, 8–10, and ≥11 have been suggested to fall
into depression categories of Bnoncase,^ Bdoubtful case,^ and
Bclinical case,^ respectively [22]. We defined our binary outcome variable as severe depressive symptoms, which we identified as HADS-D scores ≥11, despite current debate about the
optimal cut point [25].
Independent variables
Disease burden was represented by physical symptom distress
and functional dependence. Symptom distress was measured
by the 13-item Symptom Distress Scale [26], which assesses
cancer patients’ common symptoms, i.e., pain, dyspnea, and
fatigue. Scores range from 13 to 65; higher scores indicate
greater distress. Functional dependence was measured by the
10-item Enforced Social Dependency Scale (ESDS) [27].
Total ESDS scores range from 10 to 51; higher scores reflect
greater dependence on help for personal and social
functioning.
Social support was measured by the 19-item Medical
Outcomes Study Social Support Scale (MOS-SSS) [28]. The
MOS-SSS has five subscales measuring perceived availability
of support that is tangible (material aid or practical assistance),
affectionate (affection and expressions of love), emotional
(expression of positive emotion and empathetic understanding), and informational (advice, information, or feedback)
support, as well as positive social interactions. Positive social
interactions refer to the availability of someone with whom to
relax, have a good time, engage in enjoyable activities, and
temporarily distract one from worrisome issues. Total raw
scores for each subscale are calculated and transformed into
a 0–100 scale. Higher subscale scores indicate more perceived
social support in that specific dimension.
SPB was measured by the 10-item Self-Perceived Burden
scale (SPBS) [29]. SPB was hypothesized as a multidimensional construct stemming from dependence on others to provide assistance and leading to guilt about causing hardship for
caregivers [29]. Items on the SPBS include perceptions of
guilt, indebtedness, helplessness, and worries or concerns that
caregiving may interfere with the caregiver’s life and health.
The latter feelings focus on concerns about effects on the
caregiver’s physical health, emotional and mental health,
and the financial costs of care. Each item is rated on a 5point scale from 1 (none of the time) to 5 (all of the time);
higher scores indicate greater self-perceived burden to others.
An SPBS cutoff score of ≥20 was established in a validation
study to distinguish between advanced cancer patients with
high or low SPB [30]. This cutoff score has been used in other
studies [18, 31].
Confounding variables
To determine the unique associations of prevalence of severe
depressive symptoms with precipitating and buffering roles
for disease burden (symptom distress and functional dependence) as well as SPB and social support, we identified and
controlled for socio-demographics and stressor (cancer) characteristics as potential confounders. Socio-demographics included gender, age, marital status, educational level, religious
affiliation, and financial sufficiency (categorized into perceived financial sufficiency to make ends meet and financial
strain). Stressor characteristics were measured by the severity
of cancer, including diagnosis, post-diagnostic survival at
study enrollment, time since recognition of terminally ill status at each data collection, and metastatic and comorbidity
status.
Statistical analysis
Data were first descriptively analyzed to check the distribution of all study variables. Baseline characteristics and
outcome variables were compared among participants
who died, withdrew, and were still alive at the end of
study follow-ups by chi-square and multivariate analysis
of variance. When significant differences were found,
Tukey’s studentized range (HSD) tests were conducted
to identify differences among the three groups, thus controlling for type I errors. To explore changes in the prevalence of severe depressive symptoms, time proximity to
the patient’s death was determined as the period between
death and the day of interview. Time proximity to the
patient’s death was further categorized as 1 to 30, 31 to
90, 91–180, and 181–365 days, the conventional periods
for estimating survival of cancer patients [32].
Associations between the likelihood of experiencing
severe depressive symptoms and hypothesized independent variables were examined using multivariate logistic
regression modeling with the generalized estimating equation (GEE) [33] based on our interest in populationaveraged effects instead of subject-specific effects [34].
Furthermore, the GEE uses robust standard error estimates
[33, 34] to account for within-subject correlations of
HADS-D scores during follow-up and to allow the timing
and number of repeated assessments to differ across patients to accommodate missing data. The GEE assumes
data are missing due to covariate-dependent missingness
[34, 35]. In other words, missingness is explained by observed model covariates, e.g., symptom distress and functional dependence, the most common reasons for terminally ill cancer patients to drop out/withdraw from our
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study. These covariates are also hypothesized to be associated with participants’ severe depressive symptoms in
their last year of life. Under the assumption of covariatedependent missingness, the GEE method handles missing
data by list-wise deletion (or complete case analysis), thus
excluding subjects with missing data from the analysis
[34, 35]. Model fits were evaluated by the quasilikelihood under the independence model criterion (QIC)
and QICu statistics [36]. QIC and QICu are analogous to
the Akaike information criterion (AIC) and corrected AIC
statistics, respectively, for comparing model fit with
quasi-likelihood-based methods. Lower QIC and QICu
scores indicate better model fit. The regression estimate
for each independent variable was exponentiated to retransform into adjusted odds ratio (AOR) with 95 % confidence interval (CI).
Results
Of 433 eligible patients, 380 were enrolled (87.8 % participation). Eligible patients declined to participate primarily due to
being too weak (n = 25, 47.2 %) or uninterested (n = 22,
41.5 %) (Fig. 1). Characteristics of patients who did and did
not participate could not be compared due to restricted access
to information about those who refused to participate. Of 380
patients enrolled, 40 (10.5 %) withdrew from follow-ups primarily due to deteriorated physical condition or transferring to
hospitals close to their home and 12 (3.2 %) were still alive at
the end of follow-ups. Since we, our analysis, focused on
the last year of life, we excluded three patients whose
only data were assessed more than 1 year before their
death. The final sample comprised 325 patients who died
during the study period. These patients and those who
Fig. 1 Participant flow chart
Eligible patients (n=433)
Patients refused to
participate
1. Too weak (n=25)
2. Uninterested (n=22)
3. Other reasons (n=6)
Patients recruited (n=380)
Patients who withdrew
(n=40)
Patients who only
Patients still alive (n=12)
provided data >1 year
before death (n=3)
Final sample: 325 patients
Patients surviving by
time before death
1-30 (n=325)
31-90 (n=277)
91-180 (n=168)
181-365 (n=90)
Patients providing information by time before
patient death (days)
1-30 (n=233, assessments=338)
31-90 (n=256, assessments=684)
91-180 (n=161, assessments=587)
181-365 (n=90, assessments=562)
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withdrew or were still alive did not differ significantly at
baseline on independent variables (Table 1). However, the
Table 1 Comparison of
characteristics among participants
who died, withdrew, and were still
alive at study end
prevalence of severe depressive symptoms was significantly higher among patients who died during the study
Characteristic
Gender
Male
Died n=325
Withdrew n=40
Still alive n=12
57.5
45.0
58.3
Female
Age (years)
≤45
46–55
56–65
>65
Marital status
Married
Unmarried
Educational level
<Senior high school
≥Senior high school
Financial sufficiency
Sufficient
Financial strain
With chronic disease
Yes
No
Cancer site
42.5
55.0
41.7
15.7
25.2
28.0
31.1
7.5
40.0
37.5
15.0
16.7
41.7
16.7
25.0
80.8
19.2
76.2
23.8
66.7
33.3
59.7
40.3
60.0
40.0
58.3
41.7
83.3
16.7
88.9
11.1
80.0
20.0
60.3
39.7
42.5
57.5
66.7
33.3
Lung
9.9
7.5
Liver–pancreas
31.7
17.5
Head and neck
10.2
22.5
Other
48.3
52.5
Metastasis
Yes
75.3
72.5
No
24.7
27.5
Post-diagnosis survival at enrollment (months)
1–6
41.5
37.5
7–12
18.5
15.0
13–24
20.0
20.0
≥25
20.0
27.5
Severe depressive symptoms
Yes
54.6
23.8
No
45.4
76.2
High SPB
Yes
61.2
57.5
No
38.8
42.5
8.3
16.7
8.3
66.7
Characteristic
Still alive n=12
Died n=325
Withdrew n=40
Mean (SD)
MANOVA tests for the hypothesis of no overall status effect
Symptom distress
26.7 (7.4)
23.5 (6.8)
Functional dependence
24.8 (9.7)
21.2 (7.8)
Social support
74.9 (16.5)
76.2 (18.4)
χ2/df
3.30/2
p
0.32
10.39/6
0.11
1.64/2
0.44
0.01/2
1.00
0.85/2
0.62
4.99/2
0.08
9.09/6
0.17
0.93
0.15/2
75.0
25.0
3.00/6
0.81
7.50/2
0.02
1.99/2
0.37
Wilks’ Lambda
p
0.90
0.82
41.7
16.7
8.3
33.3
50.0
50.0
41.7
58.3
21.6 (5.7)
22.1 (10.0)
69.5 (16.7)
The difference in the prevalence of severe depressive symptoms among thethree groups is significant at p=0.02
level as indicated in italic
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(54.6 %) or those who were still alive (50.0 %) than those
who withdrew (23.8 %).
Participants were primarily male (57.5 %), over 56 years
old (58.5 %), and married (76.9 %). The most common cancer
sites were stomach (18.8 %), liver (16.6 %), pancreas
(15.1 %), head and neck (10.2 %), and lung (9.9 %). On
average, participants had been diagnosed with cancer for
18.97 months (SD=34.16, range=1–359, median=9) when
they were first interviewed and were enrolled 153.12 days
(SD=162.40, range=5–667, median=94.0) before death, with
14.8, 33.5, 24.0, and 27.7 % surviving 1–30, 31–90, 91–180,
and 181–365 days, respectively. On average, participants
completed seven follow-up interviews (SD=7, range=1–34,
median=5). The following results are based on 2050 assessments with a mean interval between interviews of 17.87 days
(SD=7.13, range=6–54, median=15).
Prevalence of terminally ill Taiwanese cancer patients’ severe depressive symptoms (HADS-D scores ≥11) increased as
death approached. This prevalence was 44.58 % (181–
365 days), 49.91 % (91–180 days), 69.44 % (31–90 days),
and 82.64 % (1–30 days) before death. The results of GEE
analysis indicated that, after controlling for confounding and
independent variables, the prevalence of severe depressive
symptoms reached significance at 31–90 and 1–30 days in
reference to 91–180 days before death (Table 2).
Furthermore, disease burden, perceived social support, and
SPB were significant predictors of severe depressive symptoms (Table 2). The likelihood of severe depressive symptoms
was significantly higher in terminally ill cancer patients who
had a higher level of symptom distress and functional dependence and greater perceived tangible support (AOR [95 % CI]
was 1.16 [1.13, 1.20], 1.09 [1.06, 1.12], and 1.03 [1.01, 1.05]
with each unit increase in SDS, ESDS, and MOS-SSS tangible
support scores, respectively). Patients who reported high SPB
were 1.77 (95 % CI: 1.25, 2.49) times more likely to be depressed than those with low SPB. However, patients who reported a higher level of perceived affectionate support and positive social interactions with their supportive network had a
significantly lower likelihood of severe depressive symptoms.
Discussion
Terminally ill Taiwanese cancer patients’ prevalence of severe
depressive symptoms increased as death approached, consistent with the common conclusion that self-reported depressive
mood is exacerbated close to death [10, 12, 37], but in contrast
with the conclusion in a review of 94 studies [1] that advanced
cancer patients in palliative settings do not invariably suffer
from depression, where palliative-care setting was a proxy for
EOL. Timing for referral to palliative care varies greatly [38];
therefore, using palliative-care setting as a proxy for time
proximity to death may not be sensitive enough to evaluate
Table 2 Associations of terminally ill Taiwanese cancer patients’
likelihood of severe depressive symptoms with disease burden, social
support, and SPB
Characteristic
AOR
95 % CI
Z
p
Time proximity to patient death (days)
1–30
1.86
1.05 3.27 2.14 0.03
31–90
1.49
1.03 2.15 2.12 0.03
181–365
1.53
0.97 2.42 1.83 0.07
91–180
Reference
Pairwise comparison of the impact of time proximity to death (days)
1–30 vs 31–90
1.25
0.75 2.08 0.85 0.40
1–30 vs 91–180
1.86
1.05 3.27 2.14 0.03
1–30 vs 181–365
1.21
0.64 2.31 0.58 0.56
31–90 vs 91–180
1.49
31–90 vs 181–365
0.97
91–180 vs 181–365
0.65
Disease burden
Symptom distress
1.16
Functional dependence
1.09
Social support
Tangible support
1.03
Affectionate support
0.97
Emotional support
0.98
Informational support
1.00
Positive social interaction 0.98
Self-perceived burden to others (SPB)
High
1.77
Low
Reference
Goodness of fit statistics for GEE models
Confounders only
Potential determinants with confounders
1.03 2.15 2.12 0.03
0.62 1.51 −0.13 0.90
0.41 1.03 −1.83 0.07
1.13 1.20 10.41 <0.001
1.06 1.12 6.56 <0.001
1.01
0.95
0.96
0.98
0.96
1.05
0.99
1.00
1.02
1.00
2.61
−2.73
−1.67
0.23
−2.13
1.25 2.49 3.25
QIC
2319.75
1422.51
0.009
0.006
0.10
0.82
0.03
0.001
QICu
2208.03
1363.20
Severe depressive symptoms were defined as HADS-D score ≥11. Patient
socio-demographics and characteristics of the stressor (cancer) were controlled for using multivariate logistic regression modeling with the generalized estimating equation
SPB self-perceived burden to others, AOR adjusted odds ratio, CI confidence interval
changes in prevalence of severe depressive symptoms as death
approaches.
Our results suggest that severe depressive symptoms at
EOL reflect suffering from greater disease burden, heavy reliance on others’ tangible support, and high SPB, which can
be modified at EOL to improve psychological well-being before the patient’s death. The likelihood of severe depressive
symptoms in the last year of life was significantly higher for
terminally ill cancer patients who endured heavy disease burden, consistent with the large body of evidence linking depressive mood with symptom distress [6, 12, 15, 39, 40] and
functional dependence [6, 15, 20, 39, 40]. Taken together,
these findings reinforce the emphasis on appropriate symptom
management and facilitating functional independence near
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EOL to relieve psychological distress and to achieve optimal
QOL and a good death for terminally ill cancer patients.
Terminally ill Taiwanese cancer patients were more likely
to experience severe depressive symptoms at EOL if they
perceived greater tangible support, but less likely to do so if
they perceived greater affectionate support and had more positive interactions with their social network. Evidence suggests
that a strong degree of social support mediates depressive
symptoms for terminally ill cancer patients [20, 39, 40].
However, social support dimensions (tangible, emotional, affectionate, and informational support, as well as positive social interactions) do not operate as one entity nor do they
influence depressive symptoms identically, as shown for newly diagnosed breast cancer patients [41]. Tangible social support, affectionate support, and positive social interactions are
particularly relevant to terminally ill Taiwanese cancer patients’ psychological well-being, but with different effects.
Asian families customarily provide concrete or tangible help
to ill family members without their asking for it [42, 43].
However, such a positive intent to provide practical assistance
with basic personal needs may not be preferred by patients
themselves [42, 43], even when they are very sick. Heavy
reliance on tangible support from others may remind terminally ill Taiwanese cancer patients of their loss of independence
and autonomy, thus exacerbating their psychological stress
and increasing the likelihood of severe depressive symptoms.
In contrast, affectionate support and positive social interactions may let terminally ill cancer patients feel loved or cared
for and temporarily enable them to escape from recognizing
that they are dying and their forthcoming death, as well as
from their symptom distress and functional dependence.
Another factor precipitating the increased likelihood of severe depressive symptoms for our participants was high SPB as
their families became exhausted by the substantial demands of
their dying process. Concern about being a burden to others has
been significantly associated in cross-sectional studies with major depression [17], depression [19], and depressive symptoms
[20]. Our study extends this line of evidence by longitudinally
assessing SPB until patient death. In collectivistic Asian cultures, interpersonal relationships function with the assumption
of mutual obligation and responsibility [43, 44]. Feeling that
one’s relationships are reciprocal, harmonious, and positive is a
basis of self-worth and self-esteem in Asian culture. For Asians,
receiving care from one’s family and perceiving that this care is
creating physical, emotional, social, and economic hardships on
the family without opportunities to restore the balance between
receiving and giving help can evoke profound concerns about
potentially negative relational outcomes [43, 44] and threaten
one’s self-esteem, leading to negative psychological outcomes
such as depressive mood.
The strengths of our study include exploring factors associated with the course of severe depressive symptoms in a
large sample of terminally ill Asian cancer patients before
and up to their death. These factors include the unique
associations/contributions of disease burden, different types
of perceived social support, and SPB apart from those of
socio-demographics, disease characteristics, and time proximity to death. However, our findings should be interpreted with
the following caveats. The representativeness of the target
population may have been compromised by convenience sampling from a single medical center, limiting the generalizability of the findings. A remarkable proportion (10.5 %) of patients withdrew from the study. One threat to the validity of
our findings is missing data—a frequent problem in longitudinal studies. The GEE assumes that data are missing due to
covariate-dependent missingness, i.e., the probability of
missingness depends on covariates [35] such as symptom distress and functional dependence. This assumption is reasonable and may reflect the primary reasons for our participants’
not completing planned interviews. However, the baseline
prevalence of severe depressive symptoms was significantly
lower for patients who withdrew from our study than those of
patients who died during the study. Whether these patients’
changes in and predictors of severe depressive symptoms are
similar to the findings reported here remain unknown.
Furthermore, GEE analysis completely excludes subjects with
missing data. We recognize that list-wise deletion of cases
with missing data weakens the statistical power of our analyses and may lead to biased results when data are missing not at
random or not related to observed covariates. Our findings are
also limited by assessing depressive symptoms with the
HADS-D rather than diagnostic interviews by psychiatrists;
using a questionnaire may overestimate the prevalence of severe depressive symptoms but avoids misrecognizing patients’ need for psychological treatment. Terminally ill cancer
patients’ likelihood of experiencing severe depressive symptoms may have been affected by factors not measured, e.g.,
awareness and acceptance of prognosis [45] and personal coping capacities or strategies [12]. Reliable assessments of participants’ depressive symptoms before study enrollment were
not available. This information would likely have strongly
predicted depressive symptoms over the dying process.
Therefore, we cannot rule out the possibility that our observations may be anchored in situations preceding the dying
process.
To comprehensively clarify the precipitating and protective
factors for terminally ill cancer patients’ likelihood of severe
depressive symptoms at EOL, future studies should consider
potential determinants such as patients’ history of psychological disturbances or psychiatric disorders before their terminal
diagnosis, accurate prognostic awareness and prognostic acceptance [45], and personal coping capacities or strategies
[12]. Studies are also urgently warranted on the impact of
terminally ill cancer patients’ severe depressive symptoms
on their actual EOL care and on family caregivers’ bereavement outcomes.
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In conclusion, our hypothesis was confirmed that the prevalence of severe depressive symptoms increases as terminally
ill cancer patients approach EOL and experience greater disease burden, heavy reliance on tangible social support from
others, and high SPB. Healthcare professionals should be
made aware of these modifiable factors to identify vulnerable
terminally ill cancer patients and facilitate earlier detection of
potentially treatable depressive mood. To break the vicious
circle of accelerating symptom severity, progressive functional decline, heavy reliance on tangible support from others,
increased SPB, and elevated likelihood of severe depressive
symptoms, effective clinical interventions should be developed and provided to vulnerable cancer patients and their
caregivers over the highly stressful dying process. Such interventions may reinforce dying patients’ sense of social belonging and relational ties and bolster/restore their fragile selfesteem derived from dependence on others, thus lightening
their SPB, diminishing the likelihood of severe depressive
symptoms, and optimizing QOL to facilitate a good death.
9.
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Funding sources National Science Council (NSC 98-2314-B-182-052
and NSC99-2628-B-182-031-MY2) and National Health Research
Institute (NHRI-EX104-10208PI)
Conflict of interest No financial or other conflict of interest to disclose.
None of the funding sources had any role in designing and conducting the
study: collecting, managing, analyzing, and interpreting the data; or preparing, reviewing, or approving the manuscript.
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19.
20.
21.
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