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62 Turkish Journal of Cancer
Volume 38, No. 2, 2008
Ege University School Of Nursing, Departments of 1
Internal Medicine Nursing and 2
Nursing Education, 3
Ege University Hospital, Oncology
Division, Izmir-Turkey
Validity and Reliability of the Edmonton
Symptom Assessment Scale in Turkish
Cancer Patients
ABSTRACT
The Edmonton Symptom Assessment Scale (ESAS)
is simple and easy to use with cancer patients.
This study was planned for the purpose of adapting and
determining the validity and reliability of the ESAS for
Turkish culture. The study was conducted in outpatient
and inpatient chemotherapy units at a university hospital
between December 2004 and February 2005. A total of
113 cancer patients participated in the research. Written
permission to conduct the research was obtained from the
facility and verbal and written consent was obtained from
the patients. Research data were collected using a questionnaire,
the ESAS and the Rotterdam Symptom Checklist
(RSC). In the ESAS validity study, language validity,
content validity and criterion-related validity were tested.
In the reliability study Cronbach?s alpha and item-total
score correlation were calculated. The patients? mean age
was 48.86?13.18. The Pearson product moment correlation
coefficient between the ESAS and RSC scores was
calculated to be r=0.75, p < 0.05. A Cronbach?s alpha coefficient
of 0.77 was determined for the ESAS. The lowest
item-total correlation on the ESAS (r=0.30, p <0.05) was
for item 10 (other, constipation) and the highest (r=0.62,
p <0.05) was for item 1 (pain). The Turkish version of the
ESAS was determined to be a valid and reliable tool for
use in Turkish individuals with cancer. [Turk J Cancer
2008;38(2):62-67]
KEY WORDS:
Cancer patient, Edmonton Symptom Assessment Scale,
Rotterdam Symptom Checklist
INTRODUCTION
Cancer patients experience many symptoms related to
both their illness and its treatment (1-4). However, there
are few valid and reliable tools that can be used in the
evaluation of symptoms experienced by cancer patients in
our country. The Edmonton Symptom Assessment Scale
(ESAS) is a visual analogue scale developed for use in
symptom assessment of palliative care patients. Health
care team?s time is limited, patients avoid discussing these
symptoms with them. In addition, they may be missed and
inadequately evaluated because there are few valid and
reliable tools in Turkey for evaluating the symptoms that
cancer patients experience.
The aim of this research was to adapt the ESAS for
Turkish culture by testing its validity and reliability to
determine if it can be put into practice and used by nurses
and thus to provide a useful tool to nurses to use in the
evaluation of their patients? symptoms.
?ZNUR USTA YESILBALKAN1
, NILAY ?ZK?T?K2
, AYFER KARADAKOVAN1
, T?LAY TURGUT3
,
BURCU KAZGAN3
Yesilbalkan et al. 63
In recent decades, the concepts regarding palliative
care has been increasing and spreading in medicine in
different countries and cultures (5,6). Symptom assessment
can be used to evaluate symptom relief, to compare
treatment responses or to demonstrate the effects of specific
rehabilitative approaches. In the palliative care setting,
the patient population is often frail, has deteriorating
health so these factors affect the ability to assess patients?
symptoms (7).
Symptom control seems to be the most important
components in palliative care setting (5,8). Many assessment
tools have been developed to measure the multidimensional
features in patients with cancer both in the
early or the advanced stage of their disease (7,9). The Edmonton
Symptom Assessment Scale (ESAS) was developed
in the Palliative Care Unit of the Edmonton General
Hospital (Canada) for use in daily symptom assessment of
palliative care patients (10). ESAS has been widely used
in palliative care settings. Bruera and MacDonald (11)
compared the ESAS with the Support Team Assessment
Schedule (STAS) (12) and found good agreement. Philip
et al. (13) compared the ESAS with the Rotterdam Symptom
Checklist and the Brief Pain Inventory validated for
the Australian population and found a good correlation.
Rees et al. (14) found practical difficulties in assessing 71
patients admitted to a British hospice, showing that patients
with a very low performance status need other tools
for symptom assessment. Dudgeon et al. (15) used ESAS
to audit the adequacy and speed in symptom control in a
Canadian palliative care hospital. Chang et al. (16) demonstrated
the good agreement between the ESAS, the Functional
Assessment Cancer Therapy (FACT), the Memorial
Symptom Assessment Scale (MSAS) and the Karnofsky
Performance Status (KPS), showing that the ESAS is a
valid instrument with a good internal consistency. Heedman
et al. (17) used ESAS for symptom assessment in
home care cancer patients. Finally, Stromgren et al. (18)
used ESAS, the European Organisation for Research and
Treatment of Cancer Quality of Life Instrument (EORTC
QLQ-30) and the Hospital Anxiety and Depression Scale
(HADS) for assessing symptoms in three palliative care
settings: in-patients, outpatients and home care patients.
The aim of this research was to adapt the ESAS for
Turkish culture by testing its validity and reliability to
determine if it can be put into practice and used by nurses
and thus to provide a useful tool to nurses to use in the
evaluation of their patients? symptoms in palliative care
units.
MATERIALS AND METHODS
Sample
A total of 130 cancer patients who were ongoing cancer
therapy were interviewed. Seventeen of these patients
didn?t want to participate in the research. The final group
was composed of 113 cancer patients (inpatient n=53,
outpatient n=60) who were 18 years or older, knew how
to read Turkish, could write, were able to communicate,
and not have been diagnosed with psychiatric disorder.
The patients were recruited from outpatient and inpatient
clinic of a university hospital in western Turkey.
Permission to conduct this study was obtained from
School of Nursing Ethical Committee, and both verbal
and written consent was obtained from each participant.
Patients were informed of the purpose of the research.
Instruments
Research data were collected using an individual identification
form, ESAS and RSC.
Individual identification form
This questionnaire was developed by the researchers
and contains 12 questions about factors related to the individuals
and their diseases.
Edmonton Symptom Assessment Scale (ESAS)
The ESAS was developed by Bruera et al. (10). The
symptoms included on the ESAS are listed as 10 items:
pain, activity, nausea, depression, anxiety, insomnia, anorexia,
not feeling very well, shortness of breath, and others.
All of the items on the ESAS have a value of 0-10
points.
Rotterdam Symptom Checklist (RSC)
The RSC is used for the evaluation of complaints that
develop related to symptoms experienced by cancer patients.
There are six subscales including psychological
and physical discomforts. The tool?s items are scored on a
64
likert type scale which ranges between 1 and 4. There are
a total of 27 items on the scale which includes 8 items on
the psychological symptoms subscale and 19 items on the
physical discomforts subscale. The lowest possible score
on the psychological complaints subscale is 8 points and
the highest is 32 points; the lowest possible score on the
physical complaints subscale is 19 and the highest is 76
points. As the score on the tool increases the greater is the
discomfort that is experienced. The validity and reliability
of the Turkish version of this tool has been established
(19).
Procedure
In the first phase of the research the tool was translated
into Turkish by 10 individuals who know both languages
(English/Turkish) well in a method that is appropriate to
test for language validity. Then using the back translation
method the tool was retranslated into its original language
(English) by a language export who knows English well
and the retranslation was then compared to the original
statements in the tool. In the second phase for concept
validity the draft version of the Turkish form and original
language form were given to 10 faculty members who
work in the area of cancer for their opinions. Changes
were made that were necessary according to the expert
opinions. In the third phase, before the form was implemented,
in addition to language validity, a pilot study was
conducted to test if the items were understandable with
a group of 10 individuals who met the study inclusion
criteria. Statements that were unclear were corrected and
the tool was written in its final form. In the fourth phase
the ESAS and RSC were given to 113 cancer patients and
a validity technique to determine the validity of the tool
(criterion-related validity), a reliability technique to determine
the internal consistency (item-total score correlation)
and Cronbach?s alpha were calculated.
Statistical analysis
A statistician conducted the statistical analysis. The
data obtained in the research were analyzed using the
SPSS (Statistical Package for Social Sciences for Windows),
Version 11.0. The patients? descriptive information
was calculated as a distribution in number and percentage.
Student?s t-test was conducted to determine the difference
between the means from the ESAS and RSC scores. In the
criterion-related validity of the ESAS the Pearson product
Table 1
Symptoms Experienced by Patients (ESAS)
Comparison of means was done with t-test
SD: Standard deviation; NS: Not significant
Symptoms
1. Pain
2. Activity
3. Nausea
4. Depression
5. Anxiety
6. Insomnia
7. Anorexia
8. Not feeling well
9. Shortness of breath
10. Other (Constipation)
Mean
3.01
4.27
2.82
2.88
3.90
2.54
3.38
3.42
1.32
1.24
SD
3.20
3.22
3.24
2.85
5.81
3.26
3.63
3.19
2.60
1.29
Mean
2.15
3.67
2.72
2.53
2.90
1.43
2.95
2.68
0.72
0.00
SD
2.83
3.09
3.29
2.93
3.19
2.57
3.67
3.11
1.91
0.00
Mean
3.98
4.96
2.94
3.28
5.04
3.79
3.87
4.25
2.00
0.51
SD
3.34
3.26
3.23
2.73
7.67
3.52
3.57
3.10
3.09
1.87
0.0021
0.0323
NS
NS
0.0508
0.0001
NS
0.0088
0.0084
0.0367
Hospitalized
patients
(n=53)
Ambulatory
patients
(n=60)
All Patients
(n=113)
P
Validity and Reliability of the Edmonton Symptom Assessment Scale in Turkish Cancer Patients
Yesilbalkan et al. 65
moment correlation coefficient between the ESAS and
RSC scores was determined. To determine the internal
consistency of the ESAS the Cronbach?s alpha coefficient
and the item-total score correlations were calculated. For
all analyses a p value less than 0.05 was accepted as statistically
significant.
RESULTS
General characteristics of sample
In the first phase of the study 130 cancer patients were
interviewed. From these patients there were 113 who
completed both the ESAS and the RSC. Because 17 patients
did not completely fill in the forms they were not
included in the study. The mean age of the patients was
48.86?13.18 years. The majority were women (54%),
married (86.7%), primary school graduates (29.2%), lived
together with their spouses (44.2%), were unemployed
(80.5%) and had moderate economic level (71.7%). It was
also determined that there were more patients in this research
who had diagnoses of gastrointestinal (27.4%) and
breast cancer (26.5%) than other types of cancer.
Symptoms
The patients in the research stated that constipation
was an ?other? (item 10) problem that they experienced.
The mean ESAS symptom scores for both ambulatory
and hospitalized patients are shown in table 1. The mean
symptom scores were significantly higher in the hospitalized
patients for pain (p <0.05), activity (p <0.05), anxiety
(p <0.05), insomnia (p <0.05), not feeling well (p <0.05),
and shortness of breath (p <0.05).
The mean scores for the shared items in ESAS and
RSC are shown in table 2. In the ESAS, other than the
symptoms of insomnia (p >0.05) and shortness of breath
(p >0.05), the means for the scores of the other symptoms
(nausea, anxiety, depression, anorexia) were significantly
higher compared to the RSC.
Reliability
The highest mean score obtained on the ESAS was for
item 2 (Activity, X=4.27) and the lowest mean score was
for item 10 (Constipation, X=1.24). The Cronbach?s alpha
coefficient for ESAS in this research was determined to
be 0.77. The lowest item-total correlation on the ESAS
was for item 10 (r=0.30, p <0.05) (Other, Constipation)
and the highest was for item 1 (r=0.62, p <0.05).
Validity
The Pearson product moment correlation coefficient
between the ESAS and RSC scores was determined to be
r=0.75 (p <0.05).
Table 2
Symptoms Experienced by Patients According to ESAS and RSC
Comparison of mean was done with t-test
SD: Standard deviation; NS: Not significant
Symptoms
1. Pain
2. Activity
3. Nausea
4. Depression
5. Anxiety
6. Insomnia
7. Anorexia
8. Not feeling well
9. Shortness of breath
Mean
3.01
4.27
2.82
2.88
3.90
2.54
3.38
3.42
1.32
SD
3.20
3.22
3.25
2.85
5.82
3.26
3.64
3.19
2.61
Mean
_
_
2.12
2.37
2.02
1.96
2.22
_
1.67
SD
_
_
1.11
1.01
0.92
1.12
1.21
_
1.09
P
_
_
0.006
0.039
0.001
NS
<0.001
_
NS
ESAS (n=113) RSC (n=113)
66 Validity and Reliability of the Edmonton Symptom Assessment Scale in Turkish Cancer Patients
DISCUSSION
The results of this research show that the ESAS is a
simple and well accepted tool that can be used in studies
conducted with Turkish cancer patients.
The patients in this research were observed to be able
to easily fill in the ESAS. However patients tended to give
higher scores on the ESAS to symptoms found on both the
ESAS and the RSC. Based on this result it appears that
nurses may need to give more explanation to patients in
the use of the ESAS, because patients are able to adjust to
the differences in these types of tools.
Validity
Validity is the most important issue in the evaluation
of an instrument of measurement. Validity states how accurately
an instrument measures a characteristic that it
was intended to measure. Validity can be proven in three
ways with content validity, criterion-related validity, and
construct validity (20-23). In this research the ESAS was
tested for validity using content validity and criterion-related
validity.
After the ESAS?s content validity was tested in this
research the concurrent validity approach was used as it
is the most commonly used method of testing criterionrelated
validity in the literature. In concurrent validity
the correlation is calculated between the scores obtained
from the tool under investigation and a tool which has
had its validity and reliability confirmed (21,22). In this
study the RSC, which has been tested for validity and
reliability with Turkish cancer patients, was used to test
the concurrent validity of the ESAS. The scores obtained
from the ESAS and RSC were compared and evaluated in
the ESAS?s criterion-related validity test. Positive correlations
at a high level were determined between the ESAS
and RSC (p < 0.05). Based on this result it can be said that
the two tools can be used in studies for the evaluation of
symptoms in cancer patients. In the study by Bruera and
MacDonald (11) a good correlation was found between
the ESAS and the Support Team Assessment Schedule;
in the study by Chang et al (16). a correlation was found
between the ESAS and Functional Assessment of Cancer
Therapy-FACT and the Memorial Symptom Assessment
Scale (MSAS). Philip et al. (13) compared the ESAS with
the Rotterdam Symptom Checklist and the Brief Pain Inventory
validated for the Australian population and found
a good correlation.
Reliability
Reliability is the quality of a measurement tool?s ability
to measure without error. Internal consistency was used
to test the ESAS?s reliability in this research. The ESAS?s
internal consistency Cronbach?s alpha and item-total
score correlation technique was used. For the Cronbach?s
alpha tool reliability test the measurement of internal consistency
of the items in the measurement tool is the most
frequently used (24). Cronbach?s alpha coefficient ranges
between 0 and 1 and the closer to 1 means the greater the
reliability of a tool (21, 24-26).
The Cronbach?s alpha value obtained for ESAS in this
research was found to be 0.77. In the study by Chang et
al. (16) a Cronbach?s alpha value of 0.79 was obtained for
ESAS. These study results show that Cronbach?s alpha
value is at a high level that is satisfactory.
The item-total score correlation compares and examines
the variance between an item on a test with the variance
of the total test score. For an item-total score correlation
to be acceptable it needs to be at least 0.20. Having
an item score below 0.20 means that that item needs to
be removed because it is decreasing the tool?s reliability
(27). In this research the ESAS?s item-total correlation
coefficients varied between 0.30-0.62. Because none of
the item correlation coefficients were below 0.20 on the
Turkish version of the ESAS, none of the items were removed.
In this research the 10th item on the Turkish version
of the ESAS was determined to be the symptom of
constipation.
CONCLUSION
These research results show that the ESAS is a valid
tool for use with patients in the medical oncology group.
The ESAS primarily evaluated physical wellness. This
tool can be used in future studies for evaluation of symptoms.
Yesilbalkan et al. 67
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