- Email: [email protected]
Cross-Cultural Application of the Korean Version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care
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Vol. 41 No. 2 February 2011
Brief Methodological Report
Cross-Cultural Application of the Korean Version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care Dong Wook Shin, MD, MBA, Ji Eun Choi, RN, PhD, Mitsunori Miyashita, RN, PhD, Jin Young Choi, MPH, DrPH, Jina Kang, MEA, Young Ji Baik, BS, Ha Na Mo, BS, Jeanno Park, MD, PhD, Hea-Ja Kim, RN, and Eun Cheol Park, MD, PhD Department of Family Meidicine (D.W.S), Seoul National University Hospital, Seoul; National Cancer Control Institute (J.Y.C., J.K., Y.J.B., H.N.M., E.C.P.), National Cancer Center, Goyang-si; National Evidence-Based Healthcare Collaborating Agency (J.E.C.), Seoul; Center for Palliative Care (J.P.), Bobath Memorial Hospital, Kyunggi; and Palliative Care Unit, (H.-J.K.), Daejon St. Mary Hospital, The Catholic University of Korea, Seoul, Republic of Korea; and Department of Palliative Nursing (M.M.), Health Sciences, Graduate School of Medicine, Tohoku University, Sendai, Japan
Abstract Context. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care (EORTC QLQ-C15-PAL) is a shortened version of the EORTC QLQ-C30, developed for use in advanced cancer patients. Objectives. We evaluated the psychometric properties of the Korean version of the EORTC QLQ-C15-PAL to determine if this tool can be used to evaluate Korean patients with cancer who receive palliative care. Methods. A multicenter, cross-sectional survey was performed in palliative care units and hospices in Korea from September to October 2009. A total of 102 patients with cancer completed the questionnaires that included the EORTC QLQ-C15-PAL. Results. The compliance rate was high, with the missing rate for each item ranging from 0% to 7.8% (mean 3.1%). A multitrait scaling analysis revealed good convergent and discriminant validity, with only three scaling errors. The Cronbach’s alpha coefficients ranged from 0.65 to 0.89. The questionnaire discriminated among patient subgroups with different clinical profiles (e.g., performance status and degree of oral intake), thereby demonstrating the clinical validity of this tool. Conclusion. Our findings indicate that the Korean version of the EORTC QLQ-C15-PAL is a reliable and valid instrument with regard to its psychometric
Address correspondence to: Eun Cheol Park, MD, PhD, National Cancer Control Institute, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Ó 2011 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved.
Gyeonggi-do 410-769, Republic of Korea. E-mail: [email protected] Accepted for publication: May 18, 2010. 0885-3924/$ - see front matter doi:10.1016/j.jpainsymman.2010.05.009
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properties. This tool is suitable for measuring quality of life, particularly with regard to physical aspects, in Korean cancer patients who receive palliative care. J Pain Symptom Manage 2011;41:478e484. Ó 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Validation, Korean, cancer, palliative care, EORTC-C15-PAL
Introduction Patients are the preferred source of information about palliative care, particularly with regard to symptoms, functional problems, and quality of life.1 However, patients with advanced cancer often cannot tolerate the burden of a standard questionnaire. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care (EORTC QLQ-C15-PAL) is a shortened version of the EORTC QLQ-C30, which is one of the most rigorously studied and widely used health-related quality-of-life questionnaires in oncology research.1e3 The EORTC QLQ-C15-PAL was developed on the basis of qualitative interviews with patients and health care professionals and by shortening of original questionnaires by item response theory methods. This shortened tool still evaluates a range of relevant issues and maintains the reliability and validity of the original tool.4 The Korean version of the EORTC QLQC30 was cross-culturally validated by means of a rigorous translation-back-translation process and a field study with 170 patients with various types and stages of cancer.5 The shortened version (i.e., the EORTC QLQ-C15-PAL) does not require separate translation and is available on the EORTC Quality of Life Group website.6 Patients with advanced cancer are common in palliative care settings; however, the study population in this previous study included a limited number of patients with advanced cancer, that is, only 7.6% (13 of 170) of the patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 3e4. This limitation made it difficult to evaluate the applicability of the tool in palliative care settings. Furthermore, the study had a low response rate and compliance because of the physical and mental limitations of patients with advanced cancer. Here, we evaluated the psychometric properties of the Korean version
of the EORTC QLQ-C15-PAL to determine if this tool is appropriate for use in Korean patients with cancer who receive palliative care.
Methods Study Design, Subjects, and Data Collection This study was performed as a part of a national initiative to evaluate the quality of care in palliative care units and hospices that were designated for the care of cancer patients by the Korean Ministry of Health, Welfare, and Family Affairs. A multicenter, cross-sectional survey was performed from September to October 2009. Trained research assistants from the National Cancer Center visited each palliative care unit and hospice center as independent surveyors for a single full day. Study approval was obtained from institutional review boards of the National Cancer Center and from the institutional review boards of each participating center, wherever applicable. Patients were considered eligible for participation if they 1) were cancer patients with limited life expectancy (e.g., months), who were not currently undergoing anticancer treatment; 2) were admitted to the palliative care unit at least 72 hours before completing the survey; 3) were 18 years or older; and 4) were considered physically and mentally capable of participating in the survey, as judged by a member of the staff (e.g., the nurse in charge or the care coordinator). Eligibility assessments were made by reviewing medical records with the assistance of a member of the medical staff. Eligible patients were approached by independent surveyors, who explained the purpose of the study. Patients who agreed to participate were given a survey and asked to complete the questionnaire without assistance, if possible. However, surveyors provided assistance when needed for reasons such as low visual acuity.
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Instruments The survey questionnaire included the EORTC QLQ-C15-PAL. The EORTC QLQC15-PAL incorporates two functional scales (i.e., physical and emotional); two multi-item symptom scales (i.e., fatigue, pain); five single-item symptom scales (i.e., nausea and vomiting, dyspnea, insomnia, appetite loss, and constipation); and one single-item quality-of-life scale.4 All items are scored on 4-point Likert scales that range from 1 (not at all) to 4 (very much), with the exception of one item on the global health/quality-oflife scale, which uses a modified 7-point linear analogue scale.
Statistical Analyses A range of statistical analyses was performed to evaluate the reliability and validity of the data. Multitrait scaling analyses were performed to assess the item convergent validity and the item discriminate validity, and scaling errors were counted.7 Statistical analyses were performed using SAS version 9.1 (SAS Institute, Cary, NC), according to established scoring guidelines.8 Statistical significance was defined as P # 0.05 on twotailed analyses.
Results Study Participants Of the 390 patients in palliative care at the time of the survey, 222 patients were not eligible because they were currently receiving active treatment (n ¼ 21), younger than 18 years (n ¼ 1), admitted to the palliative care unit less than 72 hours before the survey (n ¼ 24), or not considered suitable because of their physical or mental condition (n ¼ 176). Of the remaining 168 eligible patients, 50 did not agree to participate in the study and an additional 16 could not complete the EORTC QLQ-C15-PAL. A total of 102 patients were included in the final analysis. The demographic characteristics of these patients are listed in Table 1.
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Table 1 Characteristics of Patient Respondents (n ¼ 102) Characteristics Age, years (mean SD)
n (%) 60.1 12.5
Sex Male Female
54 (52.9) 48 (47.1)
Cancer type Stomach Lung Liver Colorectal Breast Cervix Brain and spinal cord Head and neck Pancreas Biliary Others
19 12 9 16 2 7 3 1 9 6 18
(18.6) (11.8) (8.8) (15.7) (2.0) (6.9) (2.9) (1.0) (8.8) (5.9) (17.6)
Metastasis Brain Liver Lung Bone/spine Peritoneum Others
2 22 20 25 21 22
(2.0) (21.6) (19.6) (24.5) (20.6) (21.6)
ECOG performance status 0 1 2 3 4
7 18 26 37 14
(6.9) (17.6) (25.5) (36.3) (13.7)
Mental Alert Drowsy
95 (93.1) 7 (6.9)
Symptoms Poor oral intake Edema Ascites Deliriuma
31 40 19 6
Patient insight Awareness of cancer Awareness of terminal status
97 (95.1) 80 (78.4)
Education Primary school Middle school High school College and above
32 16 30 19
(33.0) (16.5) (31.9) (19.6)
Religion Christian Buddhist Catholic Other None
45 11 24 2 18
(45.0) (11.0) (24.0) (2.0) (18.0)
(30.4) (39.2) (18.6) (5.9)
SD ¼ standard deviation. a Patients who experienced episodes of delirium during admission.
Reliability and Validity Frequency Distribution of Responses The frequency distribution of responses is shown in Table 2. The missing rate for each item ranged from 0% to 7.8% (mean 3.1%).
A multitrait scaling analysis of the EORTC QLQ-C15-PAL showed that all item-own-scale correlations were well greater than 0.40 (corrected for overlap). Three scaling errors were
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Table 2 Percentage of Missing Values and Frequency Distributions of Responses (n ¼ 102) Items
Response Frequency
No.
Abbreviated Contents
Missing (%)
Not at All
A Little
Quite a Bit
Very Much
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Short walk In bed Need help Short of breath Pain Trouble sleeping Felt weak Lacked appetite Felt nauseated Been constipated Been tired Pain interference Felt tense Felt depressed
1 (1.0) 0 0 0 1 (1.0) 2 (2.0) 4 (3.9) 3 (2.9) 4 (3.9) 5 (4.9) 5 (4.9) 4 (3.9) 6 (5.9) 5 (4.9)
15 9 27 32 15 34 20 26 39 27 11 26 43 39
21 20 15 24 27 13 22 23 20 16 21 22 14 20
32 37 28 25 29 27 29 20 21 24 30 19 19 16
33 36 32 21 30 26 27 30 18 30 35 31 20 22
Item No.
Reponse Frequency Abbreviated Content
15
Missing (%)
1: Very Poor
2
3
4
5
6
7: Excellent
8 (7.8)
5
5
11
18
22
20
13
Quality of life
found. Items on the fatigue scale (e.g., Item 7 [felt weak] and Item 11 [felt tired]) were slightly more correlated with items on the appetite loss scale than with each other (r ¼ 0.68 vs. 0.65). In addition, pain interference (Item 12) was more correlated with the fatigue scale than with the other item (Item 5) on the pain scale (r ¼ 0.65 vs. 0.50). The Cronbach’s alpha coefficients for multi-item scales ranged from 0.67 (pain) to 0.85 (emotional functioning). With the exception of pain, these coefficients were greater than 0.70, which is the minimum standard recommended for reliability (Table 3).9,10
Clinical validity was examined by knowngroup comparisons. The EORTC QLQ-C15PAL discriminated among patients with different clinical profiles (Table 4). Patients with good performance status (ECOG 0e2) had significantly greater physical function than those with poor performance status, and this difference was clinically meaningful.11,12 Results differed significantly among patients with and without poor oral intake with regard to the physical functioning, role functioning, fatigue, nausea and vomiting, pain, dyspnea, and appetite loss scales.
Table 3 Multitrait Scaling Analyses, Using Pearson Correlations Among Scale Items on the EORTC QLQ C15-PAL Scale/Items Functioning scales Physical functioning Emotional functioning Symptom scales Fatigue Nausea and vomiting Pain Dyspnea Insomnia Appetite loss Constipation Global quality of life Quality of life
Item Numbers
Mean (SD)
Cronbach’s aa
Item-Own-Scale Correlationb
Item-Other-Scale Correlation
Scaling Error
1,2,3 13,14
27.9 (25.3) 61.7 (36.7)
0.81 0.85
0.66e0.89 0.75
0.00e0.52 0.19e0.49
0 0
60.8 32.5 54.9 44.8 48.3 51.5 52.9
0.78
0.65
0.31e0.68
2
0.67 d d d d
0.8 d d d d
0.21e0.65 d d d d
1 d d d d
d
d
d
d
7,11 9 5,12 4 6 8 10 15
(31.5) (37.3) (32.5) (37.7) (40.3) (39.3) (39.9)
61.5 (27.3)
All correlation coefficients were calculated using a pairwise deletion method. a Cronbach’s alpha of 0.7 indicates adequate scale reliability. b Corrected for overlap.
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Table 4 Known-Group Comparison According to ECOG PS and Oral Intake Status ECOG PS
Poor Oral Intake
0e2 (n ¼ 51)
3e4 (n ¼ 51)
P-Value
No (n ¼ 71)
Yes (n ¼ 31)
P-valuea
Functioning scales Physical functioning Emotional functioning
38.1 27.0 69.4 28.9
24.5 23.9 59.1 38.8
0.02 0.24
33.4 27.4 68.6 34.9
15.3 12.6 46.7 36.7
0.00 0.01
Symptom scales Fatigue Nausea and vomiting Pain Dyspnea Insomnia Appetite loss Constipation
55.1 28.6 32.7 33.5 48.0 25.1 42.7 34.0 41.3 35.1 45.3 34.5 49.3 34.9
62.8 32.5 32.4 38.7 57.1 34.5 45.5 39.0 50.7 41.9 53.6 40.9 54.2 41.7
0.30 0.98 0.22 0.75 0.32 0.37 0.60
54.4 32.3 25.5 35.9 50.2 32.4 39.4 38.3 44.3 40.8 42.5 39.1 50.5 38.8
75.5 24.4 48.3 35.9 65.6 30.7 57.0 33.5 57.8 38.1 72.2 31.7 58.6 42.4
0.00 0.00 0.03 0.03 0.13 0.00 0.36
Global quality of life Quality of life
65.3 21.4
60.2 29.1
0.44
61.9 26.8
60.7 29.1
0.85
Scale/Items
a
ECOG PS ¼ Eastern Cooperative Oncology Group performance status. Values are expressed as means standard deviations. Boldface type denotes items that indicate better functioning or fewer symptoms, which are both statistically and clinically significant. A mean difference of 10 points or greater was considered clinically meaningful. a According to the results of a t-test.
care centers. Compliance rates were satisfactory, and multitrait analyses confirmed the reliability and convergent/discriminant validity of this tool. The clinical validity of the EORTC QLQ-C15-PAL was demonstrated by its ability to discriminate among patient subgroups with different clinical profiles. Most (102 of 118) patients who agreed to participate in our study were able to complete the questionnaire with minimal assistance. Although there were significant differences between the characteristics of these participants and those of patients who did not participate in the survey (i.e., patients included in our study generally had good performance status and mental status; data not shown), our results confirm the feasibility and clinical usefulness of the EORTC QLQ-C15-PAL in this patient population.
Relationship Among Scales Interscale correlations revealed weak to moderate correlations among functioning scales and various symptom scales. Among symptom scales, the fatigue scale was moderately correlated with the appetite loss (r ¼ 0.74), pain (r ¼ 0.61), insomnia (r ¼ 0.55), and nausea and vomiting (r ¼ 0.48) scales. Global quality of life was moderately correlated with fatigue (r ¼ 0.43) but only weakly correlated with emotional functioning, nausea and vomiting, insomnia, appetite loss, and constipation (Table 5).
Discussion This article evaluated the psychometric properties of the EORTC QLQ-C15-PAL among cancer patients in Korean palliative
Table 5 Correlation Among Scales of the EORTC QLQ-C15-PAL Scale/Items Physical functioning (PF) Emotional functioning (EF) Fatigue (FA) Nausea and vomiting (NV) Pain (PA) Dyspnea (DY) Insomnia (SL) Appetite loss (AP) Constipation (CO) Quality of life (QL)
PF
EF
FA a
0.29
a
L0.53 L0.52a
NV
PA
DY
0.18 L0.45a 0.48a
0.36 L0.52a 0.61a 0.35a a
a
L0.42 0.33a 0.39a 0.08 0.41a
SL
AP
CO
0.15 L0.46a 0.55a 0.44a 0.35a 0.11
0.36 L0.45a 0.74a 0.56a 0.45a 0.21b 0.50a a
QL
0.23 0.27a 0.38a 0.46a 0.38a 0.28a 0.24b 0.37a b
0.14 0.30a L0.43a 0.24b 0.09 0.14 0.25b 0.37a 0.18b
All correlation coefficients were calculated using a pairwise deletion method. Boldface type denotes moderate to high correlation (<0.40 ¼ weak correlation, 0.40e0.60 ¼ moderate correlation, >0.60 ¼ high correlation). a P < 0.01. b P < 0.05.
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Validation of EORTC QLQ-C15-PAL in Korea
The three scaling errors in our study are not surprising from a clinical perspective. Anorexia-cachexia syndrome leads to the loss of skeletal muscle, which, in turn, reduces muscle strength and endurance and causes fatigue.13 These symptoms are often reported concomitantly by the patient.14 Our data also revealed significant differences in fatigue according to the level of oral intake (i.e., mean score 75.5 vs. 54.4; Table 4). Furthermore, pain is a well-known contributor to cancerrelated fatigue, and a previous study revealed that interference scores in the Brief Pain Inventory were moderately associated with the item scores of the Brief Fatigue Inventory (r ¼ 0.43e0.58).15 The Cronbach’s alpha coefficient for the pain scale (0.67) did not meet the criterion of being greater than 0.70 and was lower than that of the EORTC QLQ-C30 in Korean patients with cancer (0.78).5 However, a coefficient of 0.67 is acceptable and may reflect a reduction in the number of items in this scale. Validation studies conducted in Mexico also obtained Cronbach’s alpha coefficients greater than 0.7 in three of four multi-item scales.16 Interestingly, global quality of life was weakly correlated with many functioning and symptom scales, with the exception of fatigue. These correlations are lower than those reported for patients with cancer in Japan (range 0.37e0.69)17 and globally (range 0.26e0.62).18 This may reflect the exclusion of ‘‘overall health’’ from the global quality-oflife scale. These results are consistent with those of a known-group comparison that showed no differences in quality-of-life scores with regard to ECOG performance status or oral intake status. It also means that the quality of life experienced by cancer patients in palliative care settings is determined by factors other than symptoms and functioning, and that good palliative care can improve or maintain a patient’s quality of life even when physical conditions deteriorate. The absence of important end-of-life factors (e.g., existential problems, relationship problems, patient autonomy, and life closure) has been discussed by others19 and acknowledged by the authors of the EORTC QLQ-C15-PAL.4 In conclusion, our findings show that the Korean version of the EORTC QLQ-C15-PAL is a reliable and valid instrument with regard
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to its psychometric properties. Furthermore, this questionnaire is a suitable tool for assessing the quality of life of Korean cancer patients, especially with regard to physical aspects.
Disclosures and Acknowledgments This work was supported by a grant from the National R & D Program for Cancer Control, No. 0920350. The authors declare no conflicts of interest.
References 1. Kaasa S, Loge JH. Quality of life in palliative care: principles and practice. Palliat Med 2003;17: 11e20. 2. Jordhoy MS, Fayers P, Loge JH, et al. Quality of life in palliative cancer care: results from a cluster randomized trial. J Clin Oncol 2001;19:3884e3894. 3. Stromgren AS, Goldschmidt D, Groenvold M, et al. Self-assessment in cancer patients referred to palliative care: a study of feasibility and symptom epidemiology. Cancer 2002;94:512e520. 4. Groenvold M, Petersen MA, Aaronson NK, et al. The development of the EORTC QLQ-C15-PAL: a shortened questionnaire for cancer patients in palliative care. Eur J Cancer 2006;42:55e64. 5. Yun YH, Park YS, Lee ES, et al. Validation of the Korean version of the EORTC QLQ-C30. Qual Life Res 2004;13:863e868. 6. European Organization for Research and Treatment of Cancer Quality of Life Group. EORTC QLQ-C15-PAL. Available from http://groups.eortc. be/qol/questionnaires_qlqc15pal.htm. Accessed May 1, 2010. 7. Fayers P, Machin D. Quality of life: Assessment, analysis and interpretation. Chichester, UK: John Wiley & Sons, 2000. 8. Groenvold M, Petersen M. Addendum to the EORTC QLQ-C30 scoring manual: Scoring of the EORTC QLQ-C15-PAL. Brussels, Belgium: European Organization for Research and Treatment of Cancer, 2006. 9. Cronbach LJ. Coefficient alpha and the internal structure of tests. Psychometrika 1951;16:297e334. 10. Nunnally JC. Psychometric theory. New York: McGraw-Hill, 1994. 11. Osoba D, Rodrigues G, Myles J, et al. Interpreting the significance of changes in health-related quality-of-life scores. J Clin Oncol 1998;16:139e144. 12. King MT. The interpretation of scores from the EORTC quality of life questionnaire QLQ-C30. Qual Life Res 1996;5:555e567.
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13. Radbruch L, Strasser F, Elsner F, et al. Fatigue in palliative care patientsdan EAPC approach. Palliat Med 2008;22:13e32. 14. Stewart GD, Skipworth RJ, Fearon KC. Cancer cachexia and fatigue. Clin Med 2006;6:140e143. 15. Yun YH, Wang XS, Lee JS, et al. Validation study of the Korean version of the Brief Fatigue Inventory. J Pain Symptom Manage 2005;29:165e172. 16. Suarez-Del-Real Y, Allende-Perez S, Alf erezMancera A, et al. Validation of the Mexican-Spanish version of the EORTC QLQ-C15-PAL questionnaire for the evaluation of health-related quality of life in patients on palliative care. Psychooncology 2010. [Epub ahead of print].
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17. Kobayashi K, Takeda F, Teramukai S, et al. A cross-validation of the European Organization for Research and Treatment of Cancer QLQ-C30 (EORTC QLQ-C30) for Japanese with lung cancer. Eur J Cancer 1998;34:810e815. 18. Aaronson NK, Ahmedzai S, Bergman B, et al. The European Organization for Research and Treatment of Cancer QLQ-C30: a quality-of-life instrument for use in international clinical trials in oncology. J Natl Cancer Inst 1993;85:365e376. 19. Echteld MA, Deliens L, Onwuteaka-Philipsen B, et al. EORTC QLQ-C15-PAL: the new standard in the assessment of health-related quality of life in advanced cancer? Palliat Med 2006;20:1e2.
Journal of Pain and Symptom Management
Vol. 41 No. 2 February 2011
Brief Methodological Report
Cross-Cultural Application of the Korean Version of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care Dong Wook Shin, MD, MBA, Ji Eun Choi, RN, PhD, Mitsunori Miyashita, RN, PhD, Jin Young Choi, MPH, DrPH, Jina Kang, MEA, Young Ji Baik, BS, Ha Na Mo, BS, Jeanno Park, MD, PhD, Hea-Ja Kim, RN, and Eun Cheol Park, MD, PhD Department of Family Meidicine (D.W.S), Seoul National University Hospital, Seoul; National Cancer Control Institute (J.Y.C., J.K., Y.J.B., H.N.M., E.C.P.), National Cancer Center, Goyang-si; National Evidence-Based Healthcare Collaborating Agency (J.E.C.), Seoul; Center for Palliative Care (J.P.), Bobath Memorial Hospital, Kyunggi; and Palliative Care Unit, (H.-J.K.), Daejon St. Mary Hospital, The Catholic University of Korea, Seoul, Republic of Korea; and Department of Palliative Nursing (M.M.), Health Sciences, Graduate School of Medicine, Tohoku University, Sendai, Japan
Abstract Context. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care (EORTC QLQ-C15-PAL) is a shortened version of the EORTC QLQ-C30, developed for use in advanced cancer patients. Objectives. We evaluated the psychometric properties of the Korean version of the EORTC QLQ-C15-PAL to determine if this tool can be used to evaluate Korean patients with cancer who receive palliative care. Methods. A multicenter, cross-sectional survey was performed in palliative care units and hospices in Korea from September to October 2009. A total of 102 patients with cancer completed the questionnaires that included the EORTC QLQ-C15-PAL. Results. The compliance rate was high, with the missing rate for each item ranging from 0% to 7.8% (mean 3.1%). A multitrait scaling analysis revealed good convergent and discriminant validity, with only three scaling errors. The Cronbach’s alpha coefficients ranged from 0.65 to 0.89. The questionnaire discriminated among patient subgroups with different clinical profiles (e.g., performance status and degree of oral intake), thereby demonstrating the clinical validity of this tool. Conclusion. Our findings indicate that the Korean version of the EORTC QLQ-C15-PAL is a reliable and valid instrument with regard to its psychometric
Address correspondence to: Eun Cheol Park, MD, PhD, National Cancer Control Institute, National Cancer Center, 323 Ilsan-ro, Ilsandong-gu, Goyang-si, Ó 2011 U.S. Cancer Pain Relief Committee Published by Elsevier Inc. All rights reserved.
Gyeonggi-do 410-769, Republic of Korea. E-mail: [email protected] Accepted for publication: May 18, 2010. 0885-3924/$ - see front matter doi:10.1016/j.jpainsymman.2010.05.009
Vol. 41 No. 2 February 2011
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properties. This tool is suitable for measuring quality of life, particularly with regard to physical aspects, in Korean cancer patients who receive palliative care. J Pain Symptom Manage 2011;41:478e484. Ó 2011 U.S. Cancer Pain Relief Committee. Published by Elsevier Inc. All rights reserved. Key Words Validation, Korean, cancer, palliative care, EORTC-C15-PAL
Introduction Patients are the preferred source of information about palliative care, particularly with regard to symptoms, functional problems, and quality of life.1 However, patients with advanced cancer often cannot tolerate the burden of a standard questionnaire. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 15-Palliative Care (EORTC QLQ-C15-PAL) is a shortened version of the EORTC QLQ-C30, which is one of the most rigorously studied and widely used health-related quality-of-life questionnaires in oncology research.1e3 The EORTC QLQ-C15-PAL was developed on the basis of qualitative interviews with patients and health care professionals and by shortening of original questionnaires by item response theory methods. This shortened tool still evaluates a range of relevant issues and maintains the reliability and validity of the original tool.4 The Korean version of the EORTC QLQC30 was cross-culturally validated by means of a rigorous translation-back-translation process and a field study with 170 patients with various types and stages of cancer.5 The shortened version (i.e., the EORTC QLQ-C15-PAL) does not require separate translation and is available on the EORTC Quality of Life Group website.6 Patients with advanced cancer are common in palliative care settings; however, the study population in this previous study included a limited number of patients with advanced cancer, that is, only 7.6% (13 of 170) of the patients had an Eastern Cooperative Oncology Group (ECOG) performance status of 3e4. This limitation made it difficult to evaluate the applicability of the tool in palliative care settings. Furthermore, the study had a low response rate and compliance because of the physical and mental limitations of patients with advanced cancer. Here, we evaluated the psychometric properties of the Korean version
of the EORTC QLQ-C15-PAL to determine if this tool is appropriate for use in Korean patients with cancer who receive palliative care.
Methods Study Design, Subjects, and Data Collection This study was performed as a part of a national initiative to evaluate the quality of care in palliative care units and hospices that were designated for the care of cancer patients by the Korean Ministry of Health, Welfare, and Family Affairs. A multicenter, cross-sectional survey was performed from September to October 2009. Trained research assistants from the National Cancer Center visited each palliative care unit and hospice center as independent surveyors for a single full day. Study approval was obtained from institutional review boards of the National Cancer Center and from the institutional review boards of each participating center, wherever applicable. Patients were considered eligible for participation if they 1) were cancer patients with limited life expectancy (e.g., months), who were not currently undergoing anticancer treatment; 2) were admitted to the palliative care unit at least 72 hours before completing the survey; 3) were 18 years or older; and 4) were considered physically and mentally capable of participating in the survey, as judged by a member of the staff (e.g., the nurse in charge or the care coordinator). Eligibility assessments were made by reviewing medical records with the assistance of a member of the medical staff. Eligible patients were approached by independent surveyors, who explained the purpose of the study. Patients who agreed to participate were given a survey and asked to complete the questionnaire without assistance, if possible. However, surveyors provided assistance when needed for reasons such as low visual acuity.
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Instruments The survey questionnaire included the EORTC QLQ-C15-PAL. The EORTC QLQC15-PAL incorporates two functional scales (i.e., physical and emotional); two multi-item symptom scales (i.e., fatigue, pain); five single-item symptom scales (i.e., nausea and vomiting, dyspnea, insomnia, appetite loss, and constipation); and one single-item quality-of-life scale.4 All items are scored on 4-point Likert scales that range from 1 (not at all) to 4 (very much), with the exception of one item on the global health/quality-oflife scale, which uses a modified 7-point linear analogue scale.
Statistical Analyses A range of statistical analyses was performed to evaluate the reliability and validity of the data. Multitrait scaling analyses were performed to assess the item convergent validity and the item discriminate validity, and scaling errors were counted.7 Statistical analyses were performed using SAS version 9.1 (SAS Institute, Cary, NC), according to established scoring guidelines.8 Statistical significance was defined as P # 0.05 on twotailed analyses.
Results Study Participants Of the 390 patients in palliative care at the time of the survey, 222 patients were not eligible because they were currently receiving active treatment (n ¼ 21), younger than 18 years (n ¼ 1), admitted to the palliative care unit less than 72 hours before the survey (n ¼ 24), or not considered suitable because of their physical or mental condition (n ¼ 176). Of the remaining 168 eligible patients, 50 did not agree to participate in the study and an additional 16 could not complete the EORTC QLQ-C15-PAL. A total of 102 patients were included in the final analysis. The demographic characteristics of these patients are listed in Table 1.
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Table 1 Characteristics of Patient Respondents (n ¼ 102) Characteristics Age, years (mean SD)
n (%) 60.1 12.5
Sex Male Female
54 (52.9) 48 (47.1)
Cancer type Stomach Lung Liver Colorectal Breast Cervix Brain and spinal cord Head and neck Pancreas Biliary Others
19 12 9 16 2 7 3 1 9 6 18
(18.6) (11.8) (8.8) (15.7) (2.0) (6.9) (2.9) (1.0) (8.8) (5.9) (17.6)
Metastasis Brain Liver Lung Bone/spine Peritoneum Others
2 22 20 25 21 22
(2.0) (21.6) (19.6) (24.5) (20.6) (21.6)
ECOG performance status 0 1 2 3 4
7 18 26 37 14
(6.9) (17.6) (25.5) (36.3) (13.7)
Mental Alert Drowsy
95 (93.1) 7 (6.9)
Symptoms Poor oral intake Edema Ascites Deliriuma
31 40 19 6
Patient insight Awareness of cancer Awareness of terminal status
97 (95.1) 80 (78.4)
Education Primary school Middle school High school College and above
32 16 30 19
(33.0) (16.5) (31.9) (19.6)
Religion Christian Buddhist Catholic Other None
45 11 24 2 18
(45.0) (11.0) (24.0) (2.0) (18.0)
(30.4) (39.2) (18.6) (5.9)
SD ¼ standard deviation. a Patients who experienced episodes of delirium during admission.
Reliability and Validity Frequency Distribution of Responses The frequency distribution of responses is shown in Table 2. The missing rate for each item ranged from 0% to 7.8% (mean 3.1%).
A multitrait scaling analysis of the EORTC QLQ-C15-PAL showed that all item-own-scale correlations were well greater than 0.40 (corrected for overlap). Three scaling errors were
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Table 2 Percentage of Missing Values and Frequency Distributions of Responses (n ¼ 102) Items
Response Frequency
No.
Abbreviated Contents
Missing (%)
Not at All
A Little
Quite a Bit
Very Much
1 2 3 4 5 6 7 8 9 10 11 12 13 14
Short walk In bed Need help Short of breath Pain Trouble sleeping Felt weak Lacked appetite Felt nauseated Been constipated Been tired Pain interference Felt tense Felt depressed
1 (1.0) 0 0 0 1 (1.0) 2 (2.0) 4 (3.9) 3 (2.9) 4 (3.9) 5 (4.9) 5 (4.9) 4 (3.9) 6 (5.9) 5 (4.9)
15 9 27 32 15 34 20 26 39 27 11 26 43 39
21 20 15 24 27 13 22 23 20 16 21 22 14 20
32 37 28 25 29 27 29 20 21 24 30 19 19 16
33 36 32 21 30 26 27 30 18 30 35 31 20 22
Item No.
Reponse Frequency Abbreviated Content
15
Missing (%)
1: Very Poor
2
3
4
5
6
7: Excellent
8 (7.8)
5
5
11
18
22
20
13
Quality of life
found. Items on the fatigue scale (e.g., Item 7 [felt weak] and Item 11 [felt tired]) were slightly more correlated with items on the appetite loss scale than with each other (r ¼ 0.68 vs. 0.65). In addition, pain interference (Item 12) was more correlated with the fatigue scale than with the other item (Item 5) on the pain scale (r ¼ 0.65 vs. 0.50). The Cronbach’s alpha coefficients for multi-item scales ranged from 0.67 (pain) to 0.85 (emotional functioning). With the exception of pain, these coefficients were greater than 0.70, which is the minimum standard recommended for reliability (Table 3).9,10
Clinical validity was examined by knowngroup comparisons. The EORTC QLQ-C15PAL discriminated among patients with different clinical profiles (Table 4). Patients with good performance status (ECOG 0e2) had significantly greater physical function than those with poor performance status, and this difference was clinically meaningful.11,12 Results differed significantly among patients with and without poor oral intake with regard to the physical functioning, role functioning, fatigue, nausea and vomiting, pain, dyspnea, and appetite loss scales.
Table 3 Multitrait Scaling Analyses, Using Pearson Correlations Among Scale Items on the EORTC QLQ C15-PAL Scale/Items Functioning scales Physical functioning Emotional functioning Symptom scales Fatigue Nausea and vomiting Pain Dyspnea Insomnia Appetite loss Constipation Global quality of life Quality of life
Item Numbers
Mean (SD)
Cronbach’s aa
Item-Own-Scale Correlationb
Item-Other-Scale Correlation
Scaling Error
1,2,3 13,14
27.9 (25.3) 61.7 (36.7)
0.81 0.85
0.66e0.89 0.75
0.00e0.52 0.19e0.49
0 0
60.8 32.5 54.9 44.8 48.3 51.5 52.9
0.78
0.65
0.31e0.68
2
0.67 d d d d
0.8 d d d d
0.21e0.65 d d d d
1 d d d d
d
d
d
d
7,11 9 5,12 4 6 8 10 15
(31.5) (37.3) (32.5) (37.7) (40.3) (39.3) (39.9)
61.5 (27.3)
All correlation coefficients were calculated using a pairwise deletion method. a Cronbach’s alpha of 0.7 indicates adequate scale reliability. b Corrected for overlap.
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Table 4 Known-Group Comparison According to ECOG PS and Oral Intake Status ECOG PS
Poor Oral Intake
0e2 (n ¼ 51)
3e4 (n ¼ 51)
P-Value
No (n ¼ 71)
Yes (n ¼ 31)
P-valuea
Functioning scales Physical functioning Emotional functioning
38.1 27.0 69.4 28.9
24.5 23.9 59.1 38.8
0.02 0.24
33.4 27.4 68.6 34.9
15.3 12.6 46.7 36.7
0.00 0.01
Symptom scales Fatigue Nausea and vomiting Pain Dyspnea Insomnia Appetite loss Constipation
55.1 28.6 32.7 33.5 48.0 25.1 42.7 34.0 41.3 35.1 45.3 34.5 49.3 34.9
62.8 32.5 32.4 38.7 57.1 34.5 45.5 39.0 50.7 41.9 53.6 40.9 54.2 41.7
0.30 0.98 0.22 0.75 0.32 0.37 0.60
54.4 32.3 25.5 35.9 50.2 32.4 39.4 38.3 44.3 40.8 42.5 39.1 50.5 38.8
75.5 24.4 48.3 35.9 65.6 30.7 57.0 33.5 57.8 38.1 72.2 31.7 58.6 42.4
0.00 0.00 0.03 0.03 0.13 0.00 0.36
Global quality of life Quality of life
65.3 21.4
60.2 29.1
0.44
61.9 26.8
60.7 29.1
0.85
Scale/Items
a
ECOG PS ¼ Eastern Cooperative Oncology Group performance status. Values are expressed as means standard deviations. Boldface type denotes items that indicate better functioning or fewer symptoms, which are both statistically and clinically significant. A mean difference of 10 points or greater was considered clinically meaningful. a According to the results of a t-test.
care centers. Compliance rates were satisfactory, and multitrait analyses confirmed the reliability and convergent/discriminant validity of this tool. The clinical validity of the EORTC QLQ-C15-PAL was demonstrated by its ability to discriminate among patient subgroups with different clinical profiles. Most (102 of 118) patients who agreed to participate in our study were able to complete the questionnaire with minimal assistance. Although there were significant differences between the characteristics of these participants and those of patients who did not participate in the survey (i.e., patients included in our study generally had good performance status and mental status; data not shown), our results confirm the feasibility and clinical usefulness of the EORTC QLQ-C15-PAL in this patient population.
Relationship Among Scales Interscale correlations revealed weak to moderate correlations among functioning scales and various symptom scales. Among symptom scales, the fatigue scale was moderately correlated with the appetite loss (r ¼ 0.74), pain (r ¼ 0.61), insomnia (r ¼ 0.55), and nausea and vomiting (r ¼ 0.48) scales. Global quality of life was moderately correlated with fatigue (r ¼ 0.43) but only weakly correlated with emotional functioning, nausea and vomiting, insomnia, appetite loss, and constipation (Table 5).
Discussion This article evaluated the psychometric properties of the EORTC QLQ-C15-PAL among cancer patients in Korean palliative
Table 5 Correlation Among Scales of the EORTC QLQ-C15-PAL Scale/Items Physical functioning (PF) Emotional functioning (EF) Fatigue (FA) Nausea and vomiting (NV) Pain (PA) Dyspnea (DY) Insomnia (SL) Appetite loss (AP) Constipation (CO) Quality of life (QL)
PF
EF
FA a
0.29
a
L0.53 L0.52a
NV
PA
DY
0.18 L0.45a 0.48a
0.36 L0.52a 0.61a 0.35a a
a
L0.42 0.33a 0.39a 0.08 0.41a
SL
AP
CO
0.15 L0.46a 0.55a 0.44a 0.35a 0.11
0.36 L0.45a 0.74a 0.56a 0.45a 0.21b 0.50a a
QL
0.23 0.27a 0.38a 0.46a 0.38a 0.28a 0.24b 0.37a b
0.14 0.30a L0.43a 0.24b 0.09 0.14 0.25b 0.37a 0.18b
All correlation coefficients were calculated using a pairwise deletion method. Boldface type denotes moderate to high correlation (<0.40 ¼ weak correlation, 0.40e0.60 ¼ moderate correlation, >0.60 ¼ high correlation). a P < 0.01. b P < 0.05.
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The three scaling errors in our study are not surprising from a clinical perspective. Anorexia-cachexia syndrome leads to the loss of skeletal muscle, which, in turn, reduces muscle strength and endurance and causes fatigue.13 These symptoms are often reported concomitantly by the patient.14 Our data also revealed significant differences in fatigue according to the level of oral intake (i.e., mean score 75.5 vs. 54.4; Table 4). Furthermore, pain is a well-known contributor to cancerrelated fatigue, and a previous study revealed that interference scores in the Brief Pain Inventory were moderately associated with the item scores of the Brief Fatigue Inventory (r ¼ 0.43e0.58).15 The Cronbach’s alpha coefficient for the pain scale (0.67) did not meet the criterion of being greater than 0.70 and was lower than that of the EORTC QLQ-C30 in Korean patients with cancer (0.78).5 However, a coefficient of 0.67 is acceptable and may reflect a reduction in the number of items in this scale. Validation studies conducted in Mexico also obtained Cronbach’s alpha coefficients greater than 0.7 in three of four multi-item scales.16 Interestingly, global quality of life was weakly correlated with many functioning and symptom scales, with the exception of fatigue. These correlations are lower than those reported for patients with cancer in Japan (range 0.37e0.69)17 and globally (range 0.26e0.62).18 This may reflect the exclusion of ‘‘overall health’’ from the global quality-oflife scale. These results are consistent with those of a known-group comparison that showed no differences in quality-of-life scores with regard to ECOG performance status or oral intake status. It also means that the quality of life experienced by cancer patients in palliative care settings is determined by factors other than symptoms and functioning, and that good palliative care can improve or maintain a patient’s quality of life even when physical conditions deteriorate. The absence of important end-of-life factors (e.g., existential problems, relationship problems, patient autonomy, and life closure) has been discussed by others19 and acknowledged by the authors of the EORTC QLQ-C15-PAL.4 In conclusion, our findings show that the Korean version of the EORTC QLQ-C15-PAL is a reliable and valid instrument with regard
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to its psychometric properties. Furthermore, this questionnaire is a suitable tool for assessing the quality of life of Korean cancer patients, especially with regard to physical aspects.
Disclosures and Acknowledgments This work was supported by a grant from the National R & D Program for Cancer Control, No. 0920350. The authors declare no conflicts of interest.
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