Jpn J Clin Oncol 2014;44(2)153– 158 doi:10.1093/jjco/hyt187 Advance Access Publication 1 December 2013
Health-related Quality of Life Among Cancer Survivors in Korea: The Korea National Health and Nutrition Examination Survey Myueng Guen Oh1, Mi Ah Han2,*, Chi-Young Park3,*, Sang-Gon Park3 and Choon Hae Chung3 1
Department of Internal Medicine, Haengchon Medical Foundation, Haenam General Hospital, Haenam, 2Department of Preventive Medicine, College of Medicine, Chosun University, Gwangju and 3Department of Internal Medicine, Hemato-oncology, Chosun University Hospital, Gwangju, Republic of Korea
Received August 13, 2013; accepted November 4, 2013
Objective: The purpose of this study was to investigate the quality of life among cancer survivors compared with individuals without a history of cancer (noncancer controls) using the Korea National Health and Nutrition Examination Survey. Methods: The study subjects were 783 adult cancer survivors and 36 456 noncancer controls who participated in the third, fourth and fifth Korea National Health and Nutrition Examination Survey. Demographic factors, health-related behavior, clinical characteristics and healthrelated quality of life were assessed with self-reported questionnaires. The EuroQoL5Dimension was used to evaluate health-related quality of life. Descriptive statistics and multiple regression analysis were used to compare health-related quality of life between cancer survivors and noncancer controls. Results: About 67% were women and the mean age of the cancer survivors was 60.9 + 12.4 years. About 52% of survivors were diagnosed with cancer between 45 and 64 years, and more than half of cancer survivors were diagnosed 5 years or less before the interview. The pain/discomfort dimension was the highest reported problem: 43.6% for cancer survivors. The proportion of any reported problem was significantly higher among cancer survivors compared with noncancer controls in terms of mobility (adjusted odds ratio (aOR), 1.56, 95% confidence interval, 1.24 – 1.97), usual activities (aOR, 1.45, 95% confidence interval, 1.11 – 1.89), pain/ discomfort (aOR, 1.26, 95% confidence interval, 1.04 – 1.52) and anxiety/depression (aOR, 1.61, 95% confidence interval, 1.29 –2.01). Conclusions: Cancer survivors had a significantly lower quality of life compared with noncancer controls. The pain/discomfort dimension was the highest reported problem in cancer survivors. Key words: Korea National Health and Nutrition Examination Survey – neoplasm – quality of life – risk factors – survivors
INTRODUCTION Cancer is a major public health problem in Korea and many other parts of the world, with more than 190 000 new cancer
cases diagnosed annually. One in three people develops the disease before the age of 81 years, and one in four deaths results from cancer in Korea (1).
# The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
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*For reprints and all correspondence: Mi Ah Han, Department of Preventive Medicine, College of Medicine, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 501-759, Republic of Korea. E-mail: [email protected]; Chi-Young Park, Department of Internal Medicine, Hemato-oncology, Chosun University Hospital, 365 Pilmun-daero, Dong-gu, Gwangju 501-717, Republic of Korea. E-mail: [email protected]
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PATIENTS AND METHODS DATA SOURCE The Korea National Health and Nutrition Examination Survey (KNHANES), a cross-sectional, nationally representative survey that has been conducted by the Division of Chronic Disease Surveillance and the Korean Centers for Disease Control and Prevention since 1998, assesses the health and nutritional status of the civilian, non-institutionalized population of Korea. In this study, KNHANES III (2005), IV (2007 – 09) and V (2010– 11) were analyzed. The KNHANES III was conducted as short-term surveys over a 2- to 3-month span every 3 years, whereas the KNHANES IV and V were each conducted over the span of 1 year. Stratified clustered systematic sampling methods were used in the KNHANES. Stratification was conducted based on the 13 areas of Korea (seven metropolitan cities and six provinces), the administrative unit (dong or eup-myeon; Korean units) and the dwelling type (apartment house or others) (8). Subsequently, the population in each stratum was divided into subpopulations ( primary sampling units, PSUs), based on the geographic locations of their residences (dong/eup-myeon or tong/ban/ri; Korean units). Finally, PSUs were selected from each stratum, and sample households were categorized into PSUs using systematic sampling methods. These methods were used to ensure that the sample units are representative of the population.
The KNHANES was completed by 34 145 individuals in 2005, 4594 in 2007, 9744 in 2008, 10 533 in 2009, 8958 in 2010 and 8518 in 2011. The study subjects were 783 adult cancer survivors and 36 456 adults without a history of cancer. Adults were classified as cancer survivors in our study if they had ever been diagnosed with cancer by a physician. The KNHANES was approved by the Korea Centers for Disease Control and Prevention Institutional Review Board, and all participants signed a written informed consent. PERSONAL CHARACTERISTICS AND CLINICAL DATA DEMOGRAPHIC CHARACTERISTICS Demographic characteristics included sex, age, marital status (with or without a spouse), education (elementary school, middle school, high school and college), household income (classified into quartiles of low, middle-low, middle-high and high) and health insurance (National Health Insurance and Medical Aid Program). HEALTH BEHAVIORS AND CHRONIC CONDITIONS The following health behaviors were assessed: smoking (never, former and current), alcohol drinking (none, 1/ month, 2 – 4/month and 5/month) and physical activity (no and yes). Physical activity was measured by frequency (sessions per week) and duration (in minutes) of each session. Subjects were considered physically active if they participated in at least 30 min of moderate activity 5 days a week or at least 20 min of vigorous physical activity 3 days a week. Subjects who exercised at lower frequencies and/or durations were not considered physically active in our study. Noncancer comorbid conditions included arthritis, hypertension, diabetes mellitus, heart disease, stroke, asthma or chronic obstructive pulmonary disease. Then, the number of noncancer co-morbid conditions were calculated (none, 1 and 2). CANCER-RELATED CHARACTERISTICS Participants were classified as cancer survivors if they had been diagnosed with cancer by a physician. Participants were also asked about the cancer site and their age at diagnosis. Time since diagnosis was calculated by subtracting their age at the survey interview from their reported age at the initial cancer diagnosis. If multiple cancer diagnoses were reported, age at first diagnosis was used. No data were collected on existing cancer symptoms or treatments, so the current status of their cancer was not assessed. QUALITY-OF-LIFE ASSESSMENT HRQoL was assessed using the EuroQoL-5Dimension (EQ-5D) instrument, a short, generic HRQoL instrument, that consists of the EQ-5D descriptive system and the EQ-5D index. The descriptive system assessed five dimensions: mobility, self-care, usual activities, pain/discomfort and
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Cancer survival rates have been increasing steadily due to earlier detection, increased awareness and advances in treatment. When all sites in Korea were combined, cancer patients diagnosed between the years 2005 – 09 had a 5-year relative survival rate of 62.0% (53.2% in males and 71.4% in females), a notable improvement over previous time periods (1). This improvement in the 5-year relative survival rate has increased interest in patients’ quality of life (2 – 4). Along with survival duration, health-related quality of life (HRQoL) is an important outcome measure for cancer patients (5). HRQoL represents elements that directly affect an individual’s health, including general well-being and physical, psychological, social, spiritual and role functioning (6). HRQoL is commonly used as an outcome measure for analyzing the health impact of chronic diseases, because patient cooperation forms the core of health plans for such diseases (7). Although much research has focused on understanding cancer patients’ QoL, most of it investigates the early years of treatment (,5 years post-diagnosis) and older survivors (4). Furthermore, many of these studies were based on selective samples of patients from one or a few hospitals, limiting the potential interpretation of these studies (5). Little is known about QoL of cancer survivors in Korea despite its importance in long-term care. The purpose of our study was to investigate the quality of life among cancer survivors compared with individuals without a history of cancer in a large population-based sample.
Jpn J Clin Oncol 2014;44(2)
anxiety/depression. Each dimension had three possible responses: ‘no problems’, ‘moderate problems’ and ‘severe problems’. The EQ-5D health states were defined as a combination of the responses for each item, and the survey could yield 35 (i.e. 243) possible combinations (2,9,10). The EQ-5D instrument has been translated into Korean, and its validity and test–retest reliability have been previously demonstrated (11).
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mobility [odds ratios (ORs), 1.56; 95% confidence intervals (CIs), 1.24 – 1.97], usual activities (ORs, 1.45; 95% CIs, 1.11 – 1.89), pain/discomfort (ORs, 1.26; 95% CIs, 1.04 – 1.52) and anxiety/depression (ORs, 1.61; 95% CIs, 1.29 – 2.01) (Table 3).
DISCUSSION STATISTICAL ANALYSIS
RESULTS GENERAL CHARACTERISTICS OF STUDY SUBJECTS Our sample consisted of 50.6% women. The mean age was 48.7 + 16.5 years, with 13.1% over 65 years of age. The demographic characteristics of cancer survivors and noncancer controls were significantly different (Table 1). Cancer survivors consisted of 67.3% women. The mean age of cancer survivors was 60.9 + 12.4 years, with 37.0% over 65 years. More than 74% of survivors had a spouse. Less than elementary school education was reported by 40.4% of the survivors, and 14.4% had more than a college education. The majority (65.8%) of survivors never smoked, whereas 10.5% were current smokers. More than half (54.3%) of the survivors did not drink alcohol within the past 30 days, and 12.5% reported drinking 5 times per month. About 19.0% of the survivors engaged in regular exercise (Table 1). CLINICAL CHARACTERISTICS OF CANCER SURVIVORS About 52% survivors were diagnosed with cancer between 45 and 64 years, with the mean age at diagnosis being 53.3 + 13.0 years. More than half of cancer survivors were diagnosed 5 years or less before the interview, with the most common cancer type being stomach cancer (Table 2). EQ-5DS IN CANCER SURVIVORS AND NONCANCER CONTROLS The pain/discomfort dimension showed the highest proportion of problems, with 43.6% of respondents reporting any problem, followed by the mobility dimension, which showed 32.9% of the participants reporting a problem in cancer survivors. The lowest percentage of problems was reported in the self-care dimension in cancer survivors (9.4%, Table 3). In the binary multiple logistic regression on EQ-5D responses, cancer survivors significantly reported problems in
We have described the HRQoL of cancer survivors in Korea in terms of the EQ-5D dimensions and EQ-5D index. The EQ-5D is a standardized instrument for determining the quality of health states (12) and can be applied to a wide range of diseases and treatments (3). Recently, the EQ-5D has been used to study a variety of cancer patient groups, including groups in which the primary tumor site is the same and groups in which the primary tumor site is different (2), and a growing body of literature supports its validity and reliability. In this study, pain/discomfort was the most frequently reported EQ-5Ds in cancer survivors, with more than 43.7% of the survivors reporting moderate or severe pain/discomfort. According to statistics published by the American Cancer Society in 2002, 50 – 70% of people with cancer experience some degree of pain, which usually only intensifies as the disease progresses. Less than half get adequate pain relief, which negatively impacts their quality of life. While more than half of cancer patients have insufficient pain control, and about a quarter of them actually die in pain (13). Regular screening for pain and developing safe and effective treatments for chronic pain will help improve HRQoL in cancer survivors. The mobility dimension was the second most reported problem in cancer survivors. Data from the English National Health Service showed that moderate or severe mobility difficulties were the most commonly reported dimensions of EQ-5D (14). In a previous prospective cohort study, functional limitations were associated with a significant reduction in allcause and competing-cause survival, irrespective of clinical, lifestyle and sociodemographic factors. Failure to address physical functioning may have extensive consequences for the quality of life and longevity among cancer survivors (15). Thus, managing mobility will improve both QoL and longevity. With the exception of self-care, cancer survivors in our study reported significantly more problems in the other measured dimensions (mobility, usual activities, pain/discomfort and anxiety/depression) compared with noncancer controls. These results suggest that cancer survivors experience significantly lower HRQoL than noncancer controls. This finding is consistent with findings of other studies (3,16). Cancer survivors had statistically significantly poorer scores than did noncancer patients in terms of Medicare-managed care (16). Additionally, breast cancer survivors had poorer HRQoL than the general female population (3). Furthermore, a longitudinal study showed that a newly diagnosed cancer had a negative effect on HRQoL (17).
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All values presented were weighted to provide national estimates based on the sampling method. All data analyses were performed using the SAS software (version 9.2). Data obtained from the EQ-5D descriptive system were reported as frequencies and percentages. The three possible responses were dichotomized as ‘no problem’ or ‘any problem’, and multiple logistic regression analyses were performed with the presence of ‘any problem’ as the dependent variable.
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Table 1. Characteristics of the study population by cancer history Characteristics
Total
Self-reported history of cancer
No reported cancer history
P value
,0.001
Sex Male
16 023 (49.4)
259 (32.7)
15 764 (49.7)
Female
21 216 (50.6)
524 (67.3)
20 692 (50.3)
19– 44
16 415 (54.1)
81 (13.3)
16 334 (54.8)
45– 64
Age (years)
13 020 (32.8)
362 (49.7)
12 658 (32.5)
65
7804 (13.1)
340 (37.0)
7464 (12.7)
Mean + SD
48.7 + 16.5
60.9 + 12.4
48.5 + 16.5
,0.001
Marital status 10 426 (32.6)
192 (25.7)
10 234 (32.8)
With spouse
26 704 (67.4)
590 (74.3)
26 114 (67.2)
9903 (19.6)
360 (40.4)
9543 (19.3)
0.001
Education Elementary school Middle school
4118 (10.3)
122 (17.0)
3996 (10.2)
High school
12 993 (40.1)
199 (28.1)
12 794 (40.3)
College
10 064 (30.0)
101 (14.4)
9963 (30.3)
,0.001
Household income Low
7622 (17.4)
263 (32.1)
7359 (17.1)
Middle-low
9252 (26.2)
194 (25.8)
9058 (26.2)
Middle-high
9904 (28.7)
147 (19.6)
9757 (28.9)
High
9821 (27.8)
160 (22.6)
9661 (27.8)
35 766 (97.0)
726 (94.1)
35 040 (97.1)
1273 (3.0)
50 (5.9)
1223 (2.9)
,0.001
Health insurance National Health Insurance Medical Aid Program
,0.001
Smoking status 21 639 (53.5)
507 (65.8)
21 132 (53.3)
Former
Never
7094 (18.8)
199 (23.7)
6895 (18.8)
Current
8470 (27.7)
75 (10.5)
8395 (28.0)
None
10 410 (22.9)
435 (54.3)
9975 (22.4)
1/month
10 414 (27.8)
181 (23.7)
10 233 (27.9)
,0.001
Drinking frequency
2– 4/month
8102 (25.1)
71 (9.4)
8031 (25.3)
5/month
8189 (24.2)
92 (12.5)
8097 (24.4)
29 326 (79.2)
633 (81.0)
28 693 (79.2)
7913 (20.8)
150 (19.0)
7763 (20.8)
,0.001
Physical activity No Yes
0.319
Noncancer, co-morbid conditionsa 0
24 577 (72.6)
362 (51.5)
24 215 (73.0)
1
8136 (18.5)
236 (27.9)
7900 (18.4)
2
4526 (8.9)
185 (20.6)
4341 (8.7)
,0.001
Data are expressed n (weighted %). SD, standard deviation. a Noncancer co-morbid conditions included arthritis, hypertension, diabetes mellitus, heart disease, stroke, asthma or chronic obstructive pulmonary disease.
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Without spouse
Jpn J Clin Oncol 2014;44(2)
Table 2. Clinical characteristics of cancer survivors Characteristics
157
Table 3. EQ-5D dimensions by cancer history n (weighted %)
Self-reported history of cancer
No reported cancer history
P value
,0.001
Age at diagnosis (years) 19–44
207 (31.1)
45–64
427 (51.7)
65
148 (17.2)
Mean + SD
53.3 + 13.0
Time since diagnosis (years) 410 (54.8)
6– 10
168 (20.2)
11
204 (25.0)
Mean + SD
7.6 + 8.2
Cancer sitea Stomach Liver
218 (24.6) 39 (5.1)
Colorectum
102 (12.7)
Breastb
146 (28.5)
b
Cervix
156 (28.1)
Lung
37 (3.3)
Other
110 (18.8)
No problem
67.1
88.0
Moderate
31.0
11.6
Severe
1.9
0.4
Any problema
32.9
12.0
OR (95% CI) for any problemsb
1.56 (1.24– 1.97)
1.00
90.6
96.9
Self-care No problem Moderate
8.3
2.8
Severe
1.1
0.3
Any problema OR (95% CI) for any problemsb
9.4
,0.001
3.1
1.25 (0.87– 1.79)
1.00
No problem
76.8
91.7
Moderate
20.6
7.5
2.5
0.8
Any problem
23.2
8.3
OR (95% CI) for any problemsb
1.45 (1.11– 1.89)
Usual activities
Severe a
,0.001
a
Allows for patient to have more than one type of cancer. b Percentages are restricted to women.
1.00
Pain/discomfort
There are several limitations to using the KNHANES data to examine the HRQoL of cancer survivors. First, individuals who had been diagnosed with cancer and subsequently died before the KNHANES took place would not have had the opportunity to participate, possibly creating a selection bias. Secondly, since the KNHANES did not include information about cancer care status, we were unable to determine the proportion of cancer survivors who were actively dealing with treatment or recurrent/advanced disease versus those living with the disease and/or symptom-free. Thirdly, cancer history was based on self-reporting. In a previous Korean study, selfreported incidences of cancer were ascertained with high specificity (99%) and low sensitivity (40%) (18). In Korea, physicians often first inform a family member, and if the family member agrees, the patient is then informed. In the event that the cancer has progressed, physicians are not obligated to inform the patient. Thus, the validity of prevalent cases might be higher than incident cases. However, we cannot exclude the possibility of underreporting the cancer history. Finally, since cancer survivors living in nursing homes, long-term care facilities or hospitals were not included in the KNHANES, our results might not reflect the behaviors of all cancer patients in Korea. We report unique data on the HRQoL and related factors of long-term cancer survivors in Korea. Cancer survivors had a significantly lower quality of life compared with noncancer controls. In addition, the pain/discomfort dimension was the
No problem
56.4
75.2
Moderate
36.5
22.3
Severe
7.2
2.5
Any problema
43.6
24.8
OR (95% CI) for any problemsb
1.26 (1.04– 1.52)
1.00
,0.001
Anxiety/depression No problem
72.3
85.8
Moderate
24.4
13.2
3.3
1.0
Any problem
27.7
14.2
OR (95% CI) for any problemsb
1.61 (1.29– 2.01)
1.00
Severe a
,0.001
Data are expressed as weighted %. P values are from chi-square tests. EQ-5D, EuroQol-5Dimension; OR, odds ratio; CI, confidence interval. a Including moderate and severe problems. b Adjusted for sex, age, marital status, education, household income, health insurance, smoking status, drinking frequency, physical activity and noncancer co-morbid conditions.
highest reported problem in cancer survivors. These data represent other clinic- and small region-based samples, identify potentially vulnerable populations of survivors for clinic and public health interventions, guide the implementation of plans that would improve HRQoL in cancer patients and determine
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5
Mobility
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progress towards enhancing life after cancer for the growing population of cancer survivors.
Conflict of interest statement None declared.
References
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1. Jung KW, Won YJ, Kong HJ, Oh CM, Seo HG, Lee JS. Cancer statistics in Korea: incidence, mortality, survival and prevalence in 2010. Cancer Res Treat 2013;45:1–14. 2. Vrettos I, Kamposioras K, Kontodimopoulos N, et al. Comparing health-related quality of life of cancer patients under chemotherapy and of their caregivers. Scientific World J 2012;2012:135283. 3. Matalqah LM, Radaideh KM, Yusoff ZM, Awaisu A. Health-related quality of life using EQ-5D among breast cancer survivors in comparison with age-matched peers from the general population in the state of Penang, Malaysia. J Public Health 2011;19:475– 80. 4. Casso D, Buist DS, Taplin S. Quality of life of 5 – 10 year breast cancer survivors diagnosed between age 40 and 49. Health Qual Life Outcomes 2004;2:25. 5. Arndt V, Merx H, Stu¨rmer T, Stegmaier C, Ziegler H, Brenner H. Age-specific detriments to quality of life among breast cancer patients one year after diagnosis. Eur J Cancer 2004;40:673–80. 6. Burstro¨ m K, Johannesson M, Diderichsen F. Swedish population health-related quality of life results using the EQ-5D. Qual Life Res 2001;10:621– 35. 7. Lee WJ, Song KH, Noh JH, Choi YJ, Jo MW. Health-related quality of life using the EuroQol 5D questionnaire in Korean patients with Type 2 diabetes. J Korean Med Sci 2012;27:255– 60.
8. Cho J, Guallar E, Hsu YJ, Shin DW, Lee WC. A comparison of cancer screening practices in cancer survivors and in the general population: the Korean national health and nutrition examination survey (KNHANES) 2001–2007. Cancer Causes Control 2010;21:2203 –12. 9. Kim KI, Lee JH, Kim CH. Impaired health-related quality of life in elderly women is associated with multimorbidity: results from the Korean National Health and Nutrition Examination Survey. Gender Med 2012;9:309 –18. 10. Lee H, Oh YJ, Kim M, et al. The association of moderate renal dysfunction with impaired preference-based health-related quality of life: third Korean national health and nutritional examination survey. BMC Nephrol 2012;13:19. 11. Kim MH, Cho YS, Uhm WS, Kim S, Bae SC. Cross-cultural adaptation and validation of the Korean version of the EQ-5D in patients with rheumatic diseases. Qual Life Res 2005;14:1401 –6. 12. Lidgren M, Wilking N, Jo¨nsson B, Rehnberg C. Health related quality of life in different states of breast cancer. Qual Life Res 2007;16:1073 –81. 13. Nersesyan H, Slavin KV. Current aproach to cancer pain management: availability and implications of different treatment options. Ther Clin Risk Manage 2007;3:381 –400. 14. Glaser AW, Fraser LK, Corner J, et al. Patient-reported outcomes of cancer survivors in England 1 – 5 years after diagnosis: a cross-sectional survey. BMJ Open 2013;3:e002317. 15. Braithwaite D, Satariano WA, Sternfeld B, et al. Long-term prognostic role of functional limitations among women with breast cancer. J Natl Cancer Inst 2010;102:1468– 77. 16. Baker F, Haffer SC, Denniston M. Health-related quality of life of cancer and noncancer patients in Medicare managed care. Cancer 2003;97:674–81. 17. Boini S, Brianc¸on S, Guillemin F, Galan P, Hercberg S. Impact of cancer occurrence on health-related quality of life: a longitudinal pre-post assessment. Health Qual Life Outcomes 2004;2:4. 18. Cho LY, Kim CS, Li L, et al. Validation of self-reported cancer incidence at follow-up in a prospective cohort study. Ann Epidemiol 2009;19:644–6.
Health-related Quality of Life Among Cancer Survivors in Korea: The Korea National Health and Nutrition Examination Survey Myueng Guen Oh1, Mi Ah Han2,*, Chi-Young Park3,*, Sang-Gon Park3 and Choon Hae Chung3 1
Department of Internal Medicine, Haengchon Medical Foundation, Haenam General Hospital, Haenam, 2Department of Preventive Medicine, College of Medicine, Chosun University, Gwangju and 3Department of Internal Medicine, Hemato-oncology, Chosun University Hospital, Gwangju, Republic of Korea
Received August 13, 2013; accepted November 4, 2013
Objective: The purpose of this study was to investigate the quality of life among cancer survivors compared with individuals without a history of cancer (noncancer controls) using the Korea National Health and Nutrition Examination Survey. Methods: The study subjects were 783 adult cancer survivors and 36 456 noncancer controls who participated in the third, fourth and fifth Korea National Health and Nutrition Examination Survey. Demographic factors, health-related behavior, clinical characteristics and healthrelated quality of life were assessed with self-reported questionnaires. The EuroQoL5Dimension was used to evaluate health-related quality of life. Descriptive statistics and multiple regression analysis were used to compare health-related quality of life between cancer survivors and noncancer controls. Results: About 67% were women and the mean age of the cancer survivors was 60.9 + 12.4 years. About 52% of survivors were diagnosed with cancer between 45 and 64 years, and more than half of cancer survivors were diagnosed 5 years or less before the interview. The pain/discomfort dimension was the highest reported problem: 43.6% for cancer survivors. The proportion of any reported problem was significantly higher among cancer survivors compared with noncancer controls in terms of mobility (adjusted odds ratio (aOR), 1.56, 95% confidence interval, 1.24 – 1.97), usual activities (aOR, 1.45, 95% confidence interval, 1.11 – 1.89), pain/ discomfort (aOR, 1.26, 95% confidence interval, 1.04 – 1.52) and anxiety/depression (aOR, 1.61, 95% confidence interval, 1.29 –2.01). Conclusions: Cancer survivors had a significantly lower quality of life compared with noncancer controls. The pain/discomfort dimension was the highest reported problem in cancer survivors. Key words: Korea National Health and Nutrition Examination Survey – neoplasm – quality of life – risk factors – survivors
INTRODUCTION Cancer is a major public health problem in Korea and many other parts of the world, with more than 190 000 new cancer
cases diagnosed annually. One in three people develops the disease before the age of 81 years, and one in four deaths results from cancer in Korea (1).
# The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: [email protected]
Downloaded from http://jjco.oxfordjournals.org/ at Univ of Iowa-Law Library on June 3, 2015
*For reprints and all correspondence: Mi Ah Han, Department of Preventive Medicine, College of Medicine, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 501-759, Republic of Korea. E-mail: [email protected]; Chi-Young Park, Department of Internal Medicine, Hemato-oncology, Chosun University Hospital, 365 Pilmun-daero, Dong-gu, Gwangju 501-717, Republic of Korea. E-mail: [email protected]
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Quality of life in cancer survivors
PATIENTS AND METHODS DATA SOURCE The Korea National Health and Nutrition Examination Survey (KNHANES), a cross-sectional, nationally representative survey that has been conducted by the Division of Chronic Disease Surveillance and the Korean Centers for Disease Control and Prevention since 1998, assesses the health and nutritional status of the civilian, non-institutionalized population of Korea. In this study, KNHANES III (2005), IV (2007 – 09) and V (2010– 11) were analyzed. The KNHANES III was conducted as short-term surveys over a 2- to 3-month span every 3 years, whereas the KNHANES IV and V were each conducted over the span of 1 year. Stratified clustered systematic sampling methods were used in the KNHANES. Stratification was conducted based on the 13 areas of Korea (seven metropolitan cities and six provinces), the administrative unit (dong or eup-myeon; Korean units) and the dwelling type (apartment house or others) (8). Subsequently, the population in each stratum was divided into subpopulations ( primary sampling units, PSUs), based on the geographic locations of their residences (dong/eup-myeon or tong/ban/ri; Korean units). Finally, PSUs were selected from each stratum, and sample households were categorized into PSUs using systematic sampling methods. These methods were used to ensure that the sample units are representative of the population.
The KNHANES was completed by 34 145 individuals in 2005, 4594 in 2007, 9744 in 2008, 10 533 in 2009, 8958 in 2010 and 8518 in 2011. The study subjects were 783 adult cancer survivors and 36 456 adults without a history of cancer. Adults were classified as cancer survivors in our study if they had ever been diagnosed with cancer by a physician. The KNHANES was approved by the Korea Centers for Disease Control and Prevention Institutional Review Board, and all participants signed a written informed consent. PERSONAL CHARACTERISTICS AND CLINICAL DATA DEMOGRAPHIC CHARACTERISTICS Demographic characteristics included sex, age, marital status (with or without a spouse), education (elementary school, middle school, high school and college), household income (classified into quartiles of low, middle-low, middle-high and high) and health insurance (National Health Insurance and Medical Aid Program). HEALTH BEHAVIORS AND CHRONIC CONDITIONS The following health behaviors were assessed: smoking (never, former and current), alcohol drinking (none, 1/ month, 2 – 4/month and 5/month) and physical activity (no and yes). Physical activity was measured by frequency (sessions per week) and duration (in minutes) of each session. Subjects were considered physically active if they participated in at least 30 min of moderate activity 5 days a week or at least 20 min of vigorous physical activity 3 days a week. Subjects who exercised at lower frequencies and/or durations were not considered physically active in our study. Noncancer comorbid conditions included arthritis, hypertension, diabetes mellitus, heart disease, stroke, asthma or chronic obstructive pulmonary disease. Then, the number of noncancer co-morbid conditions were calculated (none, 1 and 2). CANCER-RELATED CHARACTERISTICS Participants were classified as cancer survivors if they had been diagnosed with cancer by a physician. Participants were also asked about the cancer site and their age at diagnosis. Time since diagnosis was calculated by subtracting their age at the survey interview from their reported age at the initial cancer diagnosis. If multiple cancer diagnoses were reported, age at first diagnosis was used. No data were collected on existing cancer symptoms or treatments, so the current status of their cancer was not assessed. QUALITY-OF-LIFE ASSESSMENT HRQoL was assessed using the EuroQoL-5Dimension (EQ-5D) instrument, a short, generic HRQoL instrument, that consists of the EQ-5D descriptive system and the EQ-5D index. The descriptive system assessed five dimensions: mobility, self-care, usual activities, pain/discomfort and
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Cancer survival rates have been increasing steadily due to earlier detection, increased awareness and advances in treatment. When all sites in Korea were combined, cancer patients diagnosed between the years 2005 – 09 had a 5-year relative survival rate of 62.0% (53.2% in males and 71.4% in females), a notable improvement over previous time periods (1). This improvement in the 5-year relative survival rate has increased interest in patients’ quality of life (2 – 4). Along with survival duration, health-related quality of life (HRQoL) is an important outcome measure for cancer patients (5). HRQoL represents elements that directly affect an individual’s health, including general well-being and physical, psychological, social, spiritual and role functioning (6). HRQoL is commonly used as an outcome measure for analyzing the health impact of chronic diseases, because patient cooperation forms the core of health plans for such diseases (7). Although much research has focused on understanding cancer patients’ QoL, most of it investigates the early years of treatment (,5 years post-diagnosis) and older survivors (4). Furthermore, many of these studies were based on selective samples of patients from one or a few hospitals, limiting the potential interpretation of these studies (5). Little is known about QoL of cancer survivors in Korea despite its importance in long-term care. The purpose of our study was to investigate the quality of life among cancer survivors compared with individuals without a history of cancer in a large population-based sample.
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anxiety/depression. Each dimension had three possible responses: ‘no problems’, ‘moderate problems’ and ‘severe problems’. The EQ-5D health states were defined as a combination of the responses for each item, and the survey could yield 35 (i.e. 243) possible combinations (2,9,10). The EQ-5D instrument has been translated into Korean, and its validity and test–retest reliability have been previously demonstrated (11).
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mobility [odds ratios (ORs), 1.56; 95% confidence intervals (CIs), 1.24 – 1.97], usual activities (ORs, 1.45; 95% CIs, 1.11 – 1.89), pain/discomfort (ORs, 1.26; 95% CIs, 1.04 – 1.52) and anxiety/depression (ORs, 1.61; 95% CIs, 1.29 – 2.01) (Table 3).
DISCUSSION STATISTICAL ANALYSIS
RESULTS GENERAL CHARACTERISTICS OF STUDY SUBJECTS Our sample consisted of 50.6% women. The mean age was 48.7 + 16.5 years, with 13.1% over 65 years of age. The demographic characteristics of cancer survivors and noncancer controls were significantly different (Table 1). Cancer survivors consisted of 67.3% women. The mean age of cancer survivors was 60.9 + 12.4 years, with 37.0% over 65 years. More than 74% of survivors had a spouse. Less than elementary school education was reported by 40.4% of the survivors, and 14.4% had more than a college education. The majority (65.8%) of survivors never smoked, whereas 10.5% were current smokers. More than half (54.3%) of the survivors did not drink alcohol within the past 30 days, and 12.5% reported drinking 5 times per month. About 19.0% of the survivors engaged in regular exercise (Table 1). CLINICAL CHARACTERISTICS OF CANCER SURVIVORS About 52% survivors were diagnosed with cancer between 45 and 64 years, with the mean age at diagnosis being 53.3 + 13.0 years. More than half of cancer survivors were diagnosed 5 years or less before the interview, with the most common cancer type being stomach cancer (Table 2). EQ-5DS IN CANCER SURVIVORS AND NONCANCER CONTROLS The pain/discomfort dimension showed the highest proportion of problems, with 43.6% of respondents reporting any problem, followed by the mobility dimension, which showed 32.9% of the participants reporting a problem in cancer survivors. The lowest percentage of problems was reported in the self-care dimension in cancer survivors (9.4%, Table 3). In the binary multiple logistic regression on EQ-5D responses, cancer survivors significantly reported problems in
We have described the HRQoL of cancer survivors in Korea in terms of the EQ-5D dimensions and EQ-5D index. The EQ-5D is a standardized instrument for determining the quality of health states (12) and can be applied to a wide range of diseases and treatments (3). Recently, the EQ-5D has been used to study a variety of cancer patient groups, including groups in which the primary tumor site is the same and groups in which the primary tumor site is different (2), and a growing body of literature supports its validity and reliability. In this study, pain/discomfort was the most frequently reported EQ-5Ds in cancer survivors, with more than 43.7% of the survivors reporting moderate or severe pain/discomfort. According to statistics published by the American Cancer Society in 2002, 50 – 70% of people with cancer experience some degree of pain, which usually only intensifies as the disease progresses. Less than half get adequate pain relief, which negatively impacts their quality of life. While more than half of cancer patients have insufficient pain control, and about a quarter of them actually die in pain (13). Regular screening for pain and developing safe and effective treatments for chronic pain will help improve HRQoL in cancer survivors. The mobility dimension was the second most reported problem in cancer survivors. Data from the English National Health Service showed that moderate or severe mobility difficulties were the most commonly reported dimensions of EQ-5D (14). In a previous prospective cohort study, functional limitations were associated with a significant reduction in allcause and competing-cause survival, irrespective of clinical, lifestyle and sociodemographic factors. Failure to address physical functioning may have extensive consequences for the quality of life and longevity among cancer survivors (15). Thus, managing mobility will improve both QoL and longevity. With the exception of self-care, cancer survivors in our study reported significantly more problems in the other measured dimensions (mobility, usual activities, pain/discomfort and anxiety/depression) compared with noncancer controls. These results suggest that cancer survivors experience significantly lower HRQoL than noncancer controls. This finding is consistent with findings of other studies (3,16). Cancer survivors had statistically significantly poorer scores than did noncancer patients in terms of Medicare-managed care (16). Additionally, breast cancer survivors had poorer HRQoL than the general female population (3). Furthermore, a longitudinal study showed that a newly diagnosed cancer had a negative effect on HRQoL (17).
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All values presented were weighted to provide national estimates based on the sampling method. All data analyses were performed using the SAS software (version 9.2). Data obtained from the EQ-5D descriptive system were reported as frequencies and percentages. The three possible responses were dichotomized as ‘no problem’ or ‘any problem’, and multiple logistic regression analyses were performed with the presence of ‘any problem’ as the dependent variable.
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Quality of life in cancer survivors
Table 1. Characteristics of the study population by cancer history Characteristics
Total
Self-reported history of cancer
No reported cancer history
P value
,0.001
Sex Male
16 023 (49.4)
259 (32.7)
15 764 (49.7)
Female
21 216 (50.6)
524 (67.3)
20 692 (50.3)
19– 44
16 415 (54.1)
81 (13.3)
16 334 (54.8)
45– 64
Age (years)
13 020 (32.8)
362 (49.7)
12 658 (32.5)
65
7804 (13.1)
340 (37.0)
7464 (12.7)
Mean + SD
48.7 + 16.5
60.9 + 12.4
48.5 + 16.5
,0.001
Marital status 10 426 (32.6)
192 (25.7)
10 234 (32.8)
With spouse
26 704 (67.4)
590 (74.3)
26 114 (67.2)
9903 (19.6)
360 (40.4)
9543 (19.3)
0.001
Education Elementary school Middle school
4118 (10.3)
122 (17.0)
3996 (10.2)
High school
12 993 (40.1)
199 (28.1)
12 794 (40.3)
College
10 064 (30.0)
101 (14.4)
9963 (30.3)
,0.001
Household income Low
7622 (17.4)
263 (32.1)
7359 (17.1)
Middle-low
9252 (26.2)
194 (25.8)
9058 (26.2)
Middle-high
9904 (28.7)
147 (19.6)
9757 (28.9)
High
9821 (27.8)
160 (22.6)
9661 (27.8)
35 766 (97.0)
726 (94.1)
35 040 (97.1)
1273 (3.0)
50 (5.9)
1223 (2.9)
,0.001
Health insurance National Health Insurance Medical Aid Program
,0.001
Smoking status 21 639 (53.5)
507 (65.8)
21 132 (53.3)
Former
Never
7094 (18.8)
199 (23.7)
6895 (18.8)
Current
8470 (27.7)
75 (10.5)
8395 (28.0)
None
10 410 (22.9)
435 (54.3)
9975 (22.4)
1/month
10 414 (27.8)
181 (23.7)
10 233 (27.9)
,0.001
Drinking frequency
2– 4/month
8102 (25.1)
71 (9.4)
8031 (25.3)
5/month
8189 (24.2)
92 (12.5)
8097 (24.4)
29 326 (79.2)
633 (81.0)
28 693 (79.2)
7913 (20.8)
150 (19.0)
7763 (20.8)
,0.001
Physical activity No Yes
0.319
Noncancer, co-morbid conditionsa 0
24 577 (72.6)
362 (51.5)
24 215 (73.0)
1
8136 (18.5)
236 (27.9)
7900 (18.4)
2
4526 (8.9)
185 (20.6)
4341 (8.7)
,0.001
Data are expressed n (weighted %). SD, standard deviation. a Noncancer co-morbid conditions included arthritis, hypertension, diabetes mellitus, heart disease, stroke, asthma or chronic obstructive pulmonary disease.
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Without spouse
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Table 2. Clinical characteristics of cancer survivors Characteristics
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Table 3. EQ-5D dimensions by cancer history n (weighted %)
Self-reported history of cancer
No reported cancer history
P value
,0.001
Age at diagnosis (years) 19–44
207 (31.1)
45–64
427 (51.7)
65
148 (17.2)
Mean + SD
53.3 + 13.0
Time since diagnosis (years) 410 (54.8)
6– 10
168 (20.2)
11
204 (25.0)
Mean + SD
7.6 + 8.2
Cancer sitea Stomach Liver
218 (24.6) 39 (5.1)
Colorectum
102 (12.7)
Breastb
146 (28.5)
b
Cervix
156 (28.1)
Lung
37 (3.3)
Other
110 (18.8)
No problem
67.1
88.0
Moderate
31.0
11.6
Severe
1.9
0.4
Any problema
32.9
12.0
OR (95% CI) for any problemsb
1.56 (1.24– 1.97)
1.00
90.6
96.9
Self-care No problem Moderate
8.3
2.8
Severe
1.1
0.3
Any problema OR (95% CI) for any problemsb
9.4
,0.001
3.1
1.25 (0.87– 1.79)
1.00
No problem
76.8
91.7
Moderate
20.6
7.5
2.5
0.8
Any problem
23.2
8.3
OR (95% CI) for any problemsb
1.45 (1.11– 1.89)
Usual activities
Severe a
,0.001
a
Allows for patient to have more than one type of cancer. b Percentages are restricted to women.
1.00
Pain/discomfort
There are several limitations to using the KNHANES data to examine the HRQoL of cancer survivors. First, individuals who had been diagnosed with cancer and subsequently died before the KNHANES took place would not have had the opportunity to participate, possibly creating a selection bias. Secondly, since the KNHANES did not include information about cancer care status, we were unable to determine the proportion of cancer survivors who were actively dealing with treatment or recurrent/advanced disease versus those living with the disease and/or symptom-free. Thirdly, cancer history was based on self-reporting. In a previous Korean study, selfreported incidences of cancer were ascertained with high specificity (99%) and low sensitivity (40%) (18). In Korea, physicians often first inform a family member, and if the family member agrees, the patient is then informed. In the event that the cancer has progressed, physicians are not obligated to inform the patient. Thus, the validity of prevalent cases might be higher than incident cases. However, we cannot exclude the possibility of underreporting the cancer history. Finally, since cancer survivors living in nursing homes, long-term care facilities or hospitals were not included in the KNHANES, our results might not reflect the behaviors of all cancer patients in Korea. We report unique data on the HRQoL and related factors of long-term cancer survivors in Korea. Cancer survivors had a significantly lower quality of life compared with noncancer controls. In addition, the pain/discomfort dimension was the
No problem
56.4
75.2
Moderate
36.5
22.3
Severe
7.2
2.5
Any problema
43.6
24.8
OR (95% CI) for any problemsb
1.26 (1.04– 1.52)
1.00
,0.001
Anxiety/depression No problem
72.3
85.8
Moderate
24.4
13.2
3.3
1.0
Any problem
27.7
14.2
OR (95% CI) for any problemsb
1.61 (1.29– 2.01)
1.00
Severe a
,0.001
Data are expressed as weighted %. P values are from chi-square tests. EQ-5D, EuroQol-5Dimension; OR, odds ratio; CI, confidence interval. a Including moderate and severe problems. b Adjusted for sex, age, marital status, education, household income, health insurance, smoking status, drinking frequency, physical activity and noncancer co-morbid conditions.
highest reported problem in cancer survivors. These data represent other clinic- and small region-based samples, identify potentially vulnerable populations of survivors for clinic and public health interventions, guide the implementation of plans that would improve HRQoL in cancer patients and determine
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5
Mobility
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Quality of life in cancer survivors
progress towards enhancing life after cancer for the growing population of cancer survivors.
Conflict of interest statement None declared.
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