Data Collection and Extraction
A data extraction form was developed to extract key information from the relevant studies. The information extracted included study characteristics (ie, authors, publication year, country, study design, and sample size), the profile of family caregivers (ie, age, gender, and relationship to patient), the clinical characteristics of elderly cancer patients (ie, cancer diagnosis, cancer stage, and course of cancer), and caregiver burden–related information (ie, the instrument used, prevalence and scores of caregiver burden, and identified factors associated with caregiver burden).
The included studies were heterogeneous in terms of caregiver burden measures used, factors explored, and different analyses applied; a narrative synthesis of study findings was performed. The study design and sample characteristics were described. The prevalence and severity of caregiver burden were briefly summarized. The extracted factors were categorized with their corresponding level of evidence rated using the “best-evidence synthesis” model,22 which were increasingly used by systematic reviews.21,23–25 “Strong evidence” means that further study is very unlikely to change our confidence in the estimate of effect. “Moderate evidence” means that further research is likely to have an impact on our confidence in the estimate of the effect and may change the results. “Limited evidence” means that further research is very likely to change the results. “Conflicting evidence” means that any estimate of effect is very uncertain. “No evidence” means that no statistically analyzed or discussed factors are presented.
Identification of Relevant Studies
The initial literature search of 7 databases identified 2181 studies after removing 1158 duplications. After title and abstract screening, 537 studies were selected for full-text assessment. Studies that did not have available full text (n = 1), did not meet the inclusion criteria (n = 420), did not present results separately for family caregivers of elderly cancer patients (n = 9), did not present patient’s age or involved younger cancer patients (n = 94), shared same sample with another included study (n = 1), and measured caregiver burden as an independent variable (n = 5) were excluded (Figure). Finally, 7 studies were included in the review.
Quality of Studies
Of the 7 included studies, 3 studies (42.9%) had a quality score of 7 and were assessed to be high-quality studies, 2 studies (28.5%) had a quality score of 6 and were rated as moderate quality studies, and 2 studies (1 study each [14.3%]), which had a quality score of 5 and 4, respectively, were low-quality studies (Table 4).
Of the included studies, 4 were conducted in the United States26,29,30,32 and one each in Israel,28 Italy,31 and Thailand,27 respectively. All the reviewed studies had been published since 1999, with 5 published since 2007 (Table 5).
These 7 studies involved 1233 eligible family caregivers (range, 30–618 eligible family caregivers). They were predominantly females (approximately 75.3%). The majority of the family caregivers were spouses (average, 65.9%; range, 26%27 to 100%28). They provided primary care to cancer patients during or after cancer treatment in 5 studies and during hospice or inpatient palliative care in 2 studies. Patients all received a diagnosis of 1 type of cancer (lung cancer32 or colorectal cancer31) in 2 studies and presented with different types of cancer in the other 5 studies.
Prevalence and Severity of Caregiver Burden
Caregiver burden was measured using 5 different validated measures including Caregiver Strain Index,26,32 Caregiver Reaction Assessment and its subscales,29,30 Zarit Burden Inventory 29-item original version28 and 22-item revised version,27 and Caregiver Burden Index.31
The prevalence of caregiver burden in family caregivers was not reported in the majority of the studies.28,30–32 Based on the 3 studies with prevalence data reported, the proportion of family caregivers who reported certain level of caregiver burden varied from 37%27 to 100%.29
Mild to moderate caregiver burden was generally reported by family caregivers.26,27,29,31 The percentage of caregivers who reported high burden ranged from 1%27 to greater than 35%.31
Associated Factors of Caregiver Burden
Twenty-two factors were identified to be associated with higher caregiver burden (Table 6). They were analyzed and grouped into 4 categories: caregiver characteristics, patient characteristics, caregiving situation, and supporting resources based on existing stress-process models of family caregiving.30,33
The examined caregiver characteristics that were associated with higher caregiver burden included sociodemographics (ie, younger age, male sex, nonwhite, single, primary or lower education, and being employed), presence of migraine or anxiety disorder, a lower score of quality of life, relationship to patient, and a lower score of self-efficacy.
Moderate evidence showed that younger age was a significant factor associated with higher caregiver burden.26,28,31 The association between relationship to patient and higher caregiver burden was reported in 2 studies with contradictory findings: siblings reported higher caregiver burden in a high-quality study,27 whereas spouses and children in a moderate-quality study.31 The evidence of the association between the other 9 caregiver characteristics factors and higher caregiver burden was still limited because it was supported by only 1 high- or moderate-quality study (Table 6).
The identified patient characteristics associated with higher caregiver burden included a lower score of physical function, unintentional weight loss of 5% or greater, presence of musculoskeletal disorder, high symptom or psychological distress, limitations in social activities, cancer type, and a lower score of self-efficacy.
Moderate evidence supported that cancer type was significantly associated with higher caregiver burden.26,27 Family caregivers of patients with solid tumors (especially nonbreast solid tumors) experienced caregiver burden. The evidence of the association between the other 6 patient characteristics factors and higher caregiver burden was also limited (Table 6).
Overall, the association between caregiving situation and caregiver burden was not well explored in the reviewed studies. The identified caregiving situation factors included assistance with activities of daily living and caregiving time. Assistance with activities of daily living, a factor supported by moderate evidence, was consistently identified to be associated with higher caregiver burden.26,27 The evidence supporting the association between caregiving time of 10h/wk or more and higher caregiver burden was limited.
The association between supporting resources and caregiver burden was scarcely examined in the reviewed studies. Limited evidence supported that lack of social support26 and insufficient financial support27 were factors contributing to higher caregiver burden.
Although caring for cancer patients is considered as shorter duration compared with caring for patients with mental diseases, it is well documented in literature that family caregivers experienced equivalent levels of burden to what caregivers of dementia did.34,35 This systematic review summarized the factors associated with higher caregiver burden in diverse settings worldwide. The evaluation of current evidence identified 3 moderate-evidence factors associated with higher caregiver burden: younger caregivers, solid tumors, and assistance with the patient’s activities of daily living. The findings of younger caregivers reporting higher caregiver burden were consistent with other studies demonstrating that younger caregivers experienced more psychological distress induced by caregiving36,37 because their activities might be more restricted and their financial status might be less secure than older caregivers.37,38 Assistance with patient’s activities of daily living was also consistently identified as a significant individual factor contributing to higher caregiver burden by other studies regardless of the disease of patients.39–41 This could be explained in that providing assistance with patient’s activities of daily living requires increased number of hours devoted to caregiving and a higher level of caregiver engagement.41
Because of the paucity of primary studies of caregiver burden among family caregivers of elderly cancer patients and the high degree of variability in terms of factors investigated, many of the factors associated with higher burden were found to be limited evidence, which was supported by only 1 reviewed study. Some of these factors such as caregivers being single, with primary or lower education or being employed, providing care to patients with decreased physical function, or high symptom or psychological distress were also supported by other caregiver studies.42–46
Although many studies suggested that female caregivers (not limited to caregivers of elderly cancer patients) experienced higher caregiver burden than did male caregivers,42–44 hypothesizing that women experience consequences of caregiving due to their typical engagement in more personal care than men in the caregiver role,47 limited evidence in this review indicated that male caregivers of elderly cancer patients reported higher caregiver burden. This probably could be explained by the cultural norms and the unique challenges and difficulties encountered by males when they have to take on the caregiving role that they are less socially prepared for. As the proportion of male caregivers keeps increasing, more studies are needed to understand male caregivers’ experiences further.
Although relationship of caregiver to patient was well established as an influencing factor of caregiver burden, it should be explored further among family caregivers of elderly cancer patients as controversial effect was observed in the reviewed studies.
As the use of different caregiver burden measures in different studies makes comparison of caregiver burden among studies impossible, we were unable to do any further analysis to identify whether cancer stage or course of cancer was an associated factor of high caregiver burden. Because of the above heterogeneities among the studies, it was impossible to pool data for meta-analysis and to determine the estimates of the effects of individual factors. As the “best-evidence synthesis” method is a useful method for making a clinical recommendation,22 the results of this systematic review should be considered as valid.
It was possible that some eligible articles were missed in this review because articles published in languages other than English were not included, which might introduce language bias. This systematic review included only observational studies. Although observational studies are the most commonly used design for caregiver burden research, it is acknowledged that observational studies are sensitive to sample selection, detection, classification, and confounders.48 As the majority of caregiver burden measures lack either theoretically or empirically defined threshold for high burden, if the cutoff score for high burden used by the studies was not appropriate, it might affect the examination of associated factors. The variations in the population of caregivers and patients studied, methodology, instruments used, and cultural norms may cause differences in factor identification in individual studies. Despite that the criteria of methodological quality assessment had been used in this systematic review, low-quality studies were not excluded in view of the very finite number of studies included. All these considerations should be taken into account when interpreting the findings.
As most of the reviewed studies were conducted in western countries, because of the differences in social patterns, culture, value, and family structure between western countries and Asian countries, as well as the differences in burden of cancer, the findings might not thoroughly reflect caregiver situation in Asian countries.
This systematic review provided a summary of factors associated with higher caregiver burden among family caregivers of elderly cancer patients. Twenty-two factors were identified to be associated with higher caregiver burden, of which 3 were supported by moderate evidence, 18 were supported by limited evidence, and 1 was a conflicting factor. In general, family caregivers who were at a younger age, caring for solid tumor patients, and providing assistance with patient’s activities of daily living tended to experience higher caregiver burden. The association between relationship of caregiver to patient and higher caregiver burden was still very uncertain.
Implications to Clinical Practice and Research
It is important to identify factors contributing to higher burden on family caregivers of older adults with cancer to target interventions at family caregivers most in need and reduce adverse health outcomes related to caregiver burden. The associated factors examined by this systematic review might provide evidence in identifying family caregivers at high risk of high caregiver burden. More high-quality studies with confounding factors identified and appropriate strategies applied are highly needed to clarify and determine the estimates of the effects of individual factors.
The authors thank Drs Nakul Saxena and Pradeep Paul George Gunapal from Health Services and Outcomes Research Department, National Healthcare Group, for the comments given on the manuscript of this study.
2. Jørgensen TL, Hallas J, Friis S, et al. Comorbidity in elderly cancer patients
in relation to overall and cancer-specific mortality. Br J Cancer
3. Mohile SG, Xian Y, Dale W, et al. Association of a cancer diagnosis with vulnerability and frailty in older Medicare beneficiaries. J Natl Cancer Inst
4. Mohile SG, Fan L, Reeve E, et al. Association of cancer with geriatric syndromes in older Medicare beneficiaries. J Clin Oncol
5. Handforth C, Clegg A, Young C, et al. The prevalence and outcomes of frailty in older cancer patients: a systematic review
. Ann Oncol
6. Garlo K, O’Leary JR, Van Ness PH, et al. Burden in caregivers of older adults with advanced illness. J Am Geriatr Soc
7. Given B, Sherwood PR. Family care for the older person with cancer. Semin Oncol Nurs
8. Zarit SH, Reever KE, Msg MPA, et al. Relatives of the impaired elderly: correlates of feelings of burden. Gerontologist
9. Flaskerud JH, Carter PA, Lee P. Distressing emotions in female caregivers of people with AIDS, age-related dementias, and advanced-stage cancers. Perspect Psychiatr Care
10. Haley WE, LaMonde LA, Han B, et al. Family caregiving in hospice: effects on psychological and health functioning among spousal caregivers of hospice patients with lung cancer or dementia. Hosp J
11. Rha SY, Park Y, Song SK, et al. Caregiving burden and the quality of life of family caregivers of cancer patients: the relationship and correlates. Eur J Oncol Nurs
12. Belgacem B, Auclair C, Fedor MC, et al. A caregiver educational program improves quality of life and burden for cancer patients and their caregivers: a randomised clinical trial. Eur J Oncol Nurs
13. Li C, Zeliadt SB, Hall IJ, et al. Burden among partner caregivers of patients diagnosed with localized prostate cancer within 1 year after diagnosis: an economic perspective. Support Care Cancer
14. Wasner M, Paal P, Borasio GD. Psychosocial care for the caregivers of primary malignant brain tumor patients. J Soc Work End Life Palliat Care
15. Whisenant M. Informal caregiving in patients with brain tumors. Oncol Nurs Forum
16. Goldstein NE, Concato J, Fried TR, et al. Factors associated with caregiver burden
among caregivers of terminally ill patients with cancer. J Palliat Care
17. Kang J, Shin DW, Choi JE, et al. Factors associated with positive consequences of serving as a family caregiver
for a terminal cancer patient. Psychooncology
20. Duckitt K, Harrington D. Risk factors for pre-eclampsia at antenatal booking: systematic review
of controlled studies. BMJ
21. Zhao JZ, Zheng H, Li LY, et al. Predictors for weight loss in head and neck cancer patients undergoing radiotherapy: a systematic review
. Cancer Nurs
22. Slavin RE. Best evidence synthesis: an intelligent alternative to meta-analysis. J Clin Epidemiol
23. Gomes B, Higginson IJ. Factors influencing death at home in terminally ill patients with cancer: systematic review
24. Zhou X, Xie H, Xie L, et al. Factors associated with lymph node metastasis in radically resected rectal carcinoids: a systematic review
and meta analysis. J Gastrointest Surg
25. Xing D, Ma JX, Ma XL, et al. A methodological, systematic review
of evidence-based independent risk factors for surgical site infections after spinal surgery. Eur Spine J
26. Hsu T, Loscalzo M, Ramani R, et al. Factors associated with high burden in caregivers of older adults with cancer. Cancer
27. Chindaprasirt J, Limpawattana P, Pakkaratho P, et al. Burdens among caregivers of older adults with advanced cancer and risk factors. Asian Pac J Cancer Prev
28. Gilbar O. Gender as a predictor of burden and psychological distress of elderly husbands and wives of cancer patients. Psychooncology
29. Andrews SC. Caregiver burden
and symptom distress in people with cancer receiving hospice care. Oncol Nurs Forum
30. Doorenbos AZ, Given B, Given CW, et al. The influence of end-of-life cancer care on caregivers. Res Nurs Health
31. Palma E, Simonetti V, Franchelli P, et al. An observational study of family caregivers’ quality of life caring for patients with a stoma. Gastroenterol Nurs
32. Porter LS, Keefe FJ, Garst J, et al. Self-efficacy for managing pain, symptoms, and function in patients with lung cancer and their informal caregivers: associations with symptoms and distress. Pain
33. Pearlin LI, Mullan JT, Semple SJ, et al. Caregiving and the stress process: an overview of concepts and their measures. Gerontologist
34. Given BA, Wyatt G, Given CW, et al. Burden and depression among caregivers of patients with cancer at the end of life. Oncol Nurs Forum
35. Kim Y, Schulz R. Family caregivers’ strains: comparative analysis of cancer caregiving with dementia, diabetes, and frail elderly caregiving. J Aging Health
36. Kim Y, Spillers RL. Quality of life of family caregivers at 2 years after a relative’s cancer diagnosis. Psychooncology
37. Kim Y, Spillers RL, Hall DL. Quality of life of family caregivers 5 years after a relative’s cancer diagnosis: follow-up of the national quality of life survey for caregivers. Psychooncology
38. Williamson GM, Shaffer DR, Schulz R. Activity restriction and prior relationship history as contributors to mental health outcomes among middle-aged and older spousal caregivers. Health Psychol
39. Molyneux GJ, McCarthy GM, McEniff S, et al. Prevalence and predictors of carer burden and depression in carers of patients referred to an old age psychiatric service. Int Psychogeriatr
40. Conde-Sala JL, Garre-Olmo J, Turro-Garriga O, et al. Differential features of burden between spouse and adult-child caregivers of patients with Alzheimer’s disease: an exploratory comparative design. Int J Nurs Stud
41. Kim H, Chang M, Rose K, et al. Predictors of caregiver burden
in caregivers of individuals with dementia. J Adv Nurs
42. Perz J, Ussher JM, Butow P, et al. Gender differences in cancer carer psychological distress: an analysis of moderators and mediators. Eur J Cancer Care (Engl)
43. Park CH, Shin DW, Choi JY, et al. Determinants of the burden and positivity of family caregivers of terminally ill cancer patients in Korea. Psychooncology
44. Adelman RD, Tmanova LL, Delgado D, et al. Caregiver burden
: a clinical review. JAMA
45. Guerriere D, Husain A, Zagorski B, et al. Predictors of caregiver burden
across the home-based palliative care trajectory in Ontario, Canada. Health Soc Care Community
46. Lee KC, Chang WC, Chou WC, et al. Longitudinal changes and predictors of caregiving burden while providing end-of-life care for terminally ill cancer patients. J Palliat Med
47. Braine ME, Wray J. Supporting Families and Carers: A Nursing Perspective
. Boca Raton, FL: CRC Press (Taylor and Francis); 2016.
48. Hammer GP, du Prel J-B, Blettner M. Avoiding bias in observational studies: part 8 in a series of articles on evaluation of scientific publications. Dtsch Arztebl Int
Keywords:Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved
Associated factors; Caregiver burden; Elderly cancer patients; Family caregiver; Systematic review