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Anxiety and Depression Associated With Caregiver Burden in Caregivers of Stroke Survivors With Spasticity
Archives of Physical Medicine and Rehabilitation journal homepage: www.archives-pmr.org Archives of Physical Medicine and Rehabilitation 2013;-:-------
ORIGINAL ARTICLE
Anxiety and Depression Associated With Caregiver Burden in Caregivers of Stroke Survivors With Spasticity Melissa S. Denno, PharmD,a Patrick J. Gillard, PharmD, MS,b Glenn D. Graham, MD,c Marco D. DiBonaventura, PhD,d Amir Goren, PhD,d Sepi F. Varon, PhD,b Richard Zorowitz, MDe From aMercer University College of Pharmacy and Health Sciences, Atlanta, GA; bAllergan, Irvine, CA; cVA Medical Center, Albuquerque, NM; d Health Sciences Practice, Kantar Health, New York, NY; and eDepartment of Physical Medicine and Rehabilitation, Johns Hopkins Bayview Medical Center, Baltimore, MD.
Abstract Objective: To investigate the relationship between anxiety/depression and caregiver burden in informal caregivers of stroke survivors with spasticity. Design: Data were collected via online surveys from informal caregivers 18 years or older who cared for stroke survivors. Setting: Internet-based survey. Participants: 2007 through 2009 U.S. National Health and Wellness Survey database or Lightspeed Research general panel respondents. Interventions: Not applicable. Main Outcome Measures: Anxiety and depression were self-reported by the caregiver as a physician diagnosis. Depression severity was measured by the Patient Health Questionnaire-9 (PHQ-9). Caregiver burden was measured by the Oberst Caregiving Burden Scale (OCBS) and the Bakas Caregiving Outcomes Scale (BCOS). Logistic regression analyses were conducted with anxiety, depression, and the PHQ-9 depression severity categories as a result of each caregiver burden scale. Results: Data were analyzed for 153 informal caregivers; they were mostly women (70.6%) and white (78.4%), with a mean age of 51.6 years. For every 1-point increase in the OCBS Difficulty Scale, the odds of anxiety or depression were 2.57 times as great (P<.001) and 1.88 times as great (PZ.007), respectively. The odds of PHQ-9 severe depression versus all other categories combined were 2.48 times as great (P<.001). For every 1-point decrease in the BCOS, the odds of anxiety or depression were 2.43 times as great (P<.001) and 2.27 times as great (PZ.002), respectively. The odds of PHQ-9 severe depression versus all other categories combined were 4.55 times as great (P<.001). Conclusions: As caregiver burden increases, caregivers are more likely to have anxiety and depression. Depression severity also increases. Providing treatment to stroke survivors with spasticity that lessens the time and more importantly, the difficulty of caregiving may lead to a reduction in caregiver anxiety and depression. Archives of Physical Medicine and Rehabilitation 2013;-:------ª 2013 by the American Congress of Rehabilitation Medicine
Stroke is the third leading cause of death and a leading cause of long-term disability in the United States.1 Of the estimated 5.7 million stroke survivors in the United States, approximately 19% to Presented as a poster to the Academy of Managed Care Pharmacy, October 13e15, 2010, St. Louis, MO. No commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a benefit on the authors or on any organization with which the authors are associated (Denno, Gillard, Graham, Varon, Zorowitz). A commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit on the author or one or more of the authors. Allergan, Inc, provided funding for the study; DiBonaventura and Goren, as employees of Kantar Health, helped design, execute, and report on the study with funding from Allergan.
38% have spasticity.2,3 Spasticity is a disorder of the sensorimotor system characterized by a velocity-dependent increase in muscle tone with exaggerated tendon jerks that may contribute to disability.4 Stroke survivors with spasticity frequently experience physical disability, secondary limb deformities, and pain that limit their ability to perform basic activities of daily living such as dressing, personal hygiene, and mobility.4,5 As a result, informal caregivers who voluntarily provide care play an important role in the lives and long-term care of stroke survivors with spasticity.6 Informal care of a stroke survivor may involve personal care; assistance with dressing, walking, and activities of daily living; as
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well as emotional and social support.7 Providing this care may result in a burden experienced by the informal caregivers that is not endured by noncaregivers. Caregiver burden is often measured by the amount of time required by the caregiver, difficulty in tasks performed, and lifestyle changes as a result of caregiving.8,9 Doan et al10 reported that the time (hours per week) an informal caregiver spends providing care for a stroke survivor with spasticity increases with increasing disability of the stroke survivor. Multiple studies have recognized that burden caused by caring for a stroke survivor is a detriment to the mental health of the caregiver.11 The literature has shown that stroke caregivers have consistently higher rates of depression (34%e52%) than noncaregiver control groups.11 Increased rates of depression may be due to factors such as the physical disability of the patient, decreased social activity of the caregiver, and level of dependency of the patient, among others.11 There is also evidence suggesting that declining caregiver health is associated more with the difficulty in providing care than the time required,8 and that caregivers of patients with less functional independence report more depressive symptoms.8,12 The aim of this study was to examine the relationship between anxiety and depression and caregiver burden among informal caregivers of stroke survivors with spasticity, an area not previously studied.
Methods Study design Data for this study were obtained through a cross-sectional internet survey (approximately 25min in length) fielded to members of an online panel who identified themselves as living in a household with a stroke survivor or caring for a stroke survivor. The study was approved by the Essex Institutional Review Board in Lebanon, New Jersey.
Study population The caregiver population for this study was obtained through the Lightspeed Research (LSR) panel respondents who were a part of the U.S. National Health and Wellness Survey (NHWS) in 2007, 2008, or 2009, and the LSR panelists at large. The NHWS is an annual cross-sectional study of subjects 18 years or older with the goal of providing “a comprehensive database of epidemiologic and treatment information, healthcare attitudes, behaviors, demographic and disease characteristics, and healthrelated outcomes.”13(p710) The LSR is a panel of more than 3.4 million respondents in 24 countries who are recruited by an optin e-mail, coregistration with LSR partners, e-newsletter campaigns, banner placements, and both internal and external affiliate networks. In order to become a panel member of the
List of abbreviations: BCOS CI LSR MS NHWS OCBS PHQ-9
Bakas Caregiving Outcomes Scale confidence interval Lightspeed Research multiple sclerosis National Health and Wellness Survey Oberst Caregiving Burden Scale Patient Health Questionnaire-9
LSR, the potential panelist must register with a unique e-mail address and password and complete an in-depth demographic registration profile. In 2007, 2008, and 2009, the NHWS was completed by 63,012, 63,000, and 75,000 members of the LSR panel, respectively. A total of 6978 respondents in either the 2007 through 2009 NHWS databases or in the LSR general panel identified themselves as providing care for a stroke survivor or patient with multiple sclerosis (MS). Although data were collected for MS caregivers, they were not a part of the scope of this article. These individuals were sent an e-mail invitation to participate in the study, which contained a link to the survey website. An e-mail reminder was sent to nonresponders 2 to 4 days after the initial invitation to remind the potential participants to complete the survey. A total of 1599 individuals responded (a 22.9% response rate), 305 (19.1%) met all inclusion criteria, and 153 (9.6%) were caregivers of stroke survivors with spasticity. Inclusion criteria were as follows: (1) 18 years or older; (2) providing care for a stroke survivor or patient with MS; (3) providing care for a patient who has spasticity (assessed by self-reported observation of spasticity [characterized by stiffness, tone, tightness, muscle resistance, pain, and contracture, as specified within the survey]); (4) providing care for at least 6 months; and (5) not self-employed or employed by an agency as a caregiver. Any formal or paid caregivers were excluded from this study and were not sent survey information. Respondents who completed the survey received points that could be accumulated and exchanged for small prizes through LSR. Data were retained for respondents who completed the survey; questions could not be skipped, except for sensitive questions such as weight and height and others with explicit “don’t know” response options.
Outcome measures Oberst Caregiving Burden Scale The Oberst Caregiving Burden Scale (OCBS) is a reliable and valid 15-item questionnaire that rates 15 different types of caregiving tasks for stroke survivors based on perceived time (OCBS-Time) and difficulty (OCBS-Difficulty) of the task.14 Each item is scored on a 5-point response scale. In response to time for each item, the caregiver chooses an amount ranging from no time (score, 1) to a great deal of time (score, 5) spent on tasks related to caregiving. In response to difficulty for each item, the caregiver chooses an amount ranging from not difficult (score, 1) to extremely difficult (score, 5). Scores were calculated by averaging across the 15 items of the time and difficulty subscales, thus achieving an average score between 1 and 5 for each subscale. Summed scores can be obtained by multiplying mean scores by 15 (eg, in order to compare results against other studies using OCBS, with possible range of 15e75), but for present purposes, mean scores were used in order to preserve the interpretability and contiguity of the original item scale scores. Higher scores represent more perceived time or difficulty of the task. Therefore, higher scores indicate increased caregiver burden. Bakas Caregiving Outcomes Scale The Bakas Caregiving Outcomes Scale (BCOS) is a reliable and valid 15-item questionnaire that measures life changes as a consequence of caregiving for a stroke survivor.9 The 15 items are scored on a 7-point scale, with responses ranging from changed for the worse (score, 1) to changed for the best (score, 7) www.archives-pmr.org
Anxiety/depression in spasticity caregivers as a consequence of caring for a stroke survivor. Scores are calculated by averaging across the 15 items, thus achieving an average score between 1 and 7, with lower scores indicating increased caregiver burden.9 Again, means rather than summed scores were used to preserve item interpretability, but can be multiplied by 15 to obtain the full 15 to 105 range. Self-reported anxiety and depression Within the survey, caregivers were asked to select whether they had ever received a diagnosis of various health conditions from a physician. Anxiety and depression were listed as conditions independent of one another. Patient Health Questionnaire-9 The Patient Health Questionnaire-9 (PHQ-9) is a reliable and valid questionnaire for the assessment of depression, derived from the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition.15 The PHQ-9 consists of 9 items, with each item having to do with symptoms of depression over the previous 2 weeks. Item responses range from not at all (0), on several days (1), on more than half the days (2), and nearly every day (3). PHQ-9 Severity Index scores range from 0 to 27 and are calculated by summing across the 9 items. PHQ-9 Severity Index scores can be categorized into level of depression severity: none (0e4), mild (5e9), moderate (10e14), moderately severe (15e19), and severe (20e27).15
Statistical analyses Multiple logistic regressions were run in SPSS 15.0a to predict anxiety and depression as a function of caregiver burden using OCBS-Time, OCBS-Difficulty, and BCOS scores. Ordered logistic regressions were used to predict the relative odds of being in any higher PHQ-9 depression severity category (vs the current category and all lower categories combined) with an increase in caregiver burden (eg, moderately to severely depressed vs none to mildly depressed), in order to assess the adjusted relative odds of clinically intuitive shifts associated with 1-unit changes in burden. Linear regressions were also used to predict PHQ-9 score with an increase in caregiver burden (OCBS-Time, OCBS-Difficulty, or BCOS scales) to complement the logistic regressions with an understanding of the units of change in burden associated with corresponding shifts across depression categories. A P value of less than .05 was considered indicative of statistical significance, and 95% confidence intervals (CIs) were calculated. All regression analyses controlled for age, sex, race, education, employment, annual household income, and caregiver relationship to the patient. These variables were controlled for because of the possible impact they have on caregiver burden and the conditions of anxiety and depression. Controlling for each of these covariates strengthens the observed association between caregiver burden and the conditions of anxiety and depression.
3 Table 1 Demographics of informal caregivers of stroke survivors with spasticity Characteristics
Caregivers (NZ153)
Age (y) Women White Graduated college Employment Employed Retired Homemaker Other Caregiver relationship with patient Daughter/son Spouse/significant other Daughter-/son-in-law Other Income $50,000 <$50,000
51.612.59 108 (70.6) 120 (78.4) 70 (45.8) 75 30 16 32
(49.0) (19.6) (10.5) (20.9)
91 27 14 21
(59.5) (17.7) (9.2) (13.7)
92 (60.1) 61 (39.9)
NOTE. Values are mean SD or n (%).
(78.4%), with a mean age of 51.6 years. The caregiver was most commonly a child of the stroke survivor (59.5%), with 17.7% being a spouse or significant other, and 9.2% being a daughter-inlaw or son-in-law.
Burden and diagnoses The BCOS scale had a Cronbach alpha of .944 for the 15 items, indicating very high reliability. The OCBS Time and Difficulty subscales had Cronbach alpha values of .913 and .938, respectively, also indicating high reliability. Caregiver burden scores for the informal caregivers of stroke survivors with spasticity are reported in table 2. The mean scores SD for OCBS-Time, OCBS-Difficulty, and BCOS were 3.08.86, 2.16.90, and 3.28.87, respectively. Of the 153 caregivers, 33 respondents (21.6%) reported that they had a physician diagnosis of anxiety, and 34 (22.2%) reported a physician diagnosis of depression. PHQ-9 categories of depression included none (44.4%), mild (19.6%), moderate (18.3%), moderately severe (10.5%), and severe (7.2%).
Demographics
OCBS-Difficulty as a predictor of anxiety, depression, and depression severity The OCBS-Difficulty score was a statistically significant predictor of anxiety, depression, and of being in any higher depression severity category as measured by the PHQ-9. For every 1-point increase in the OCBS-Difficulty score, the odds of a diagnosis of anxiety or depression were 2.57 times greater (95% CI, 1.57e 4.21; P<.001) and 1.88 times greater (95% CI, 1.19e2.99; PZ.007), respectively. The odds of being in any higher depression severity category (eg, any depression category vs no depression) were 2.48 times greater (95% CI, 1.72e3.56; P<.001) (fig 1).
The mean age, sex, race, college experience, employment status, caregiver relationship to patient, and income of the informal caregivers of stroke survivors with spasticity are listed in table 1. Most of the caregivers (NZ153) were women (70.6%) and white
OCBS-Time as a predictor of anxiety, depression, and depression severity The odds of anxiety and depression did not differ significantly with changes in the OCBS-Time score (P>.35). However, the
Results
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M.S. Denno et al Table 2 Caregiver burden of informal caregivers of stroke survivors with spasticity Measures of Caregiver Burden Caregiving burden OCBS-Time* OCBS-Difficulty* BCOSy Self-reported anxiety Self-reported depression PHQ-9 None Mild Moderate Moderately severe Severe
Respondents (NZ153) 3.08.86 2.16.90 3.28.87 33 (21.6) 34 (22.2) 68 30 28 16 11
(44.4) (19.6) (18.3) (10.5) (7.2)
NOTE. Values are mean SD or n (%). * Scores are between 1 and 5, with higher numbers indicating increased caregiver burden. y Scores are between 1 and 7, with lower numbers indicating increased caregiver burden.
odds of being in any higher depression severity category as measured by the PHQ-9 were 1.96 times greater with a 1-point increase in the OCBS-Time score (95% CI, 1.35e2.83; P<.001) (see fig 1). BCOS as a predictor of anxiety, depression, and depression severity The BCOS score, measured via responses regarding life changes, was also a statistically significant predictor of anxiety, depression, and of being in any higher depression severity category as measured by the PHQ-9. For every 1-point decrease in the BCOS, the odds of a diagnosis of anxiety or depression were 2.43 times greater (95% CI, 1.47e4.16; PZ.001) and 2.27 times greater
Fig 2 Odds ratio* (95% CI, P value) for anxiety, depression, or higher PHQ-9 categorical severity with each 1-point decrease in BCOS score. *Logistic regression model predicting odds of anxiety, depression, and higher PHQ-9 severity category based on BCOS score. Each value represents a separate regression model, predicting the outcome variable as a function of the caregiver burden variables, adjusted for age, sex, white (vs other race/ethnicity), graduated college (vs not), employed (vs not), income $50,000 (vs less), and caring for spouse or significant other (vs caring for others).
(95% CI, 1.35e3.70; PZ.002), respectively. The odds of being in any higher depression severity category were 4.55 times greater (95% CI, 2.94e7.14; P<.001) (fig 2). Caregiver burden scores as predictors of depression severity (linear regression) Figure 3 represents a change in depression severity as measured by the PHQ-9 as a function of each caregiver burden score. Based on linear regression, an increase of 2.44 points in the OCBS-Time score predicts a shift into the next-higher depression severity category (bZ2.05; 95% CI, .92e3.18; P<.001). An increase of 1.78 points in the OCBS-Difficulty score or a decrease of 1.31 points in the BCOS “life changes” score also predicts a shift into the next-higher depression severity category (bZ2.80; 95% CI, 1.76e3.85; P<.001).
Discussion
Fig 1 Odds ratio* (95% CI, P value) for anxiety, depression, or higher PHQ-9 categorical severity with each 1-point increase in OCBSTime or OCBS-Difficulty score. *Logistic regression model predicting odds of anxiety, depression, and higher PHQ-9 severity category based on OCBS-Time and OCBSDifficulty scores. Each value represents a separate regression model, predicting the outcome variable as a function of the caregiver burden variables, adjusted for age, sex, white (vs other race/ethnicity), graduated college (vs not), employed (vs not), income $50,000 (vs less), and caring for spouse or significant other (vs caring for others).
Increased caregiver burden was associated with significantly poorer mental health of informal caregivers of stroke survivors with spasticity. As caregiver burden increases, it is more likely that caregivers may have anxiety and depression. The difficulty of completing tasks associated with caregiving appears to be a stronger predictor of anxiety and depression than the time required to complete such tasks. Increases in the difficulty of tasks and in the time required for caregiving have both been shown to be associated with an increase in depression severity. Studies in several diseases show that the odds of caregiver depression and anxiety increase with an increase in caregiver burden. In a population of caregivers of patients with dementia, for example, each incremental increase in caregiver burden score was associated with a 60% to 70% increase in the risk of reporting anxiety and depression.16 Similarly, in a study by Epstein-Lubow et al,17 caregivers of patients with dementia who had persisting www.archives-pmr.org
Anxiety/depression in spasticity caregivers
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Fig 3 PHQ-9 scores predicted by each caregiver burden scale. BCOS scores >5 were excluded from the figure because only 3 individuals had scores in that range.
high caregiver burden showed significantly worsened depression survey scores 12 months into the study, when compared with caregivers without persisting high caregiver burden (PZ.029). The results of our study confirm and quantify this positive relationship between caregiver burden and the likelihood of anxiety and depression in caregivers of stroke survivors with spasticity. Consistent with previous studies mentioned, our findings demonstrated that caregiver burden, in this case quantified by the OCBS-Difficulty and BCOS “life changes” validated scales, was associated with significantly increased odds of reporting anxiety, depression, and being in a higher PHQ-9 depression severity category. Moreover, our results were comparable in magnitude to other study results that indicated increased anxiety and depression as an outcome of caregiver burden in caregivers of other disease states. We also evaluated the similarity between our population and the overall stroke populations included in other studies. In 2 studies,8,14 both time and difficulty in completing tasks were predictors of “emotional distress” (mood) and negative caregiver outcomes (measured as change in social functioning, subjective well-being, and physical health as a result of providing care) in caregivers of stroke survivors. Additionally, the difficulty subscale score was a significant independent predictor of “emotional distress” and caregiver outcomes.14 Similar findings showed that the tasks perceived as most time-consuming and most difficult were significant predictors of negative mood of the caregiver.8 Multiple tasks dealing with difficulty were independent predictors of negative caregiver mood, while only 1 task dealing with time (managing finances, bills, and forms) was an independent predictor. Only the tasks shown to be most difficult were predictors of negative caregiver outcomes.8 The results of these studies confirm our findings by demonstrating an association of both time and difficulty of tasks with anxiety and depression. We also found a stronger association between development of these psychological outcomes and the difficulty of completing tasks. Both physical disability, measured by the Barthel Index, and self-reported dependency have been found to be predictors of caregiver burden in previous studies.18 It may be possible that increased physical disability translates to www.archives-pmr.org
more difficulty associated with completing tasks, contributing to heightened caregiver burden.
Study limitations There are several limitations to this study. The study was observational and cross-sectional. Therefore, causal effects of caregiver burden on anxiety and depression could not be definitively distinguished from reverse causal effects of depression on caregiver burden. The utilization of an online survey and the low overall response rate (ie, a subset of a subgroup of respondents originally identified as caregivers for persons with stroke or MS) limit the generalizability of the results, given the possible overrepresentation of respondents with particular characteristics (eg, being relatively young and mobile, or those having access to a computer). Although potential confounding variables were controlled for in the study, it is possible that other unrecognized confounders may be present. For instance, we did not control for severity of stroke within our study. This study also does not compare outcomes for caregivers of stroke survivors with spasticity with those for patients without spasticity, so the incremental impact of spasticity on caregiver burden cannot be determined. The outcomes within this study can only be attributed to caregivers of stroke survivors with spasticity as a whole. Furthermore, the study does not allow us to determine whether physical attributes (as expected with post-stroke spasticity per se) or cognitive attributes (as generally expected with brain injury) account for most of the association with outcomes. Self-report measures used in the study, such as diagnosis with depression and anxiety, are subject to potential biases and lack of validation against clinical measures such as patient charts. There is also the possibility that caregivers without internet access may respond differently to caregiver burden than those caregivers able to use internet resources. Caregivers who were unwilling or unable to complete the entire survey (and whose data were therefore excluded from consideration) may also have differed in terms of their characteristics and motivations from those who participated fully. These caregivers would not have
6 been captured in this study. The OCBS and BCOS caregiver burden scales have also not been specifically validated in caregivers of stroke survivors with spasticity, although they have been validated in stroke survivors. Lastly, anxiety and depression were determined through caregiver self-report of physician diagnoses; thus the conditions could have been under- or overreported, based on caregiver perceptions of their diagnoses.
Conclusions Increased caregiver burden was associated with significantly poorer mental health of informal caregivers of stroke survivors with spasticity. As caregiver burden increases, caregivers are more likely to have anxiety and depression. The severity of depression may also increase. Further evaluation of the clinical significance and implications for caregiver lifestyle of the increased anxiety and depression resulting from caregiver burden, as well as a comparison of the burden on caregivers of stroke survivors with and without spasticity, is warranted. An understanding of these relationships will not only lead to a better understanding of the impact of caregiver burden, but it may also provide insight into which interventions will be most effective in reducing anxiety and depression in caregivers of stroke survivors with spasticity. While not evaluated in this study, treatment options that decrease the time, and more importantly, the difficulty of caring for a stroke survivor with spasticity may lead to a reduction in caregiver anxiety and depression. Treatment options that reduce the functional disability of the stroke survivor caused by spasticity may also translate to reduced time and difficulty of tasks completed by the caregiver. Further study is warranted.
Supplier a. IBM Corp, 1 New Orchard Rd, Armonk, NY 10504-1722.
Keywords Anxiety; Caregivers; Depression; Muscle spasticity; Rehabilitation; Stroke
Corresponding author Melissa S. Denno, PharmD, 4114 Woodlands Pkwy, Ste 500, Palm Harbor, FL 34685. E-mail address: [email protected].
M.S. Denno et al
References 1. National Stroke Association website. Available at: http://info.stroke. org/site/PageServer?pagenameZSTROKE. Accessed October 8, 2010. 2. Watkins CL, Leathley MJ, Gregson JM, Moore AP, Smith TL, Sharma AK. Prevalence of spasticity post stroke. Clin Rehabil 2002;16:515-22. 3. Sommerfeld DK, Eek EU, Svensson AK, Holmqvist LW, von Arbin MH. Spasticity after stroke: its occurrence and association with motor impairments and activity limitations. Stroke 2004;35:134-9. 4. Lance JW. The control of muscle tone, reflexes, and movement: Robert Wartenberg lecture. Neurology 1980;30:1303-13. 5. Thompson AJ, Jarrett L, Lockley L, Marsden J, Stevenson VL. Clinical management of spasticity. J Neurol Neurosurg Psychiatry 2005;76:459-63. 6. Dewey HM, Thrift AG, Mihalopoulos C, et al. Informal care for stroke survivors: results from the North East Melbourne Stroke Incidence Study (NEMESIS). Stroke 2002;33:1028-33. 7. Ski C, O’Connell B. Stroke: the increasing complexity of carer needs. J Neurosci Nurs 2007;39:172-9. 8. Bakas T, Austin JK, Jessup SL, Williams LS, Oberst MT. Time and difficulty of tasks provided by family caregivers of stroke survivors. J Neurosci Nurs 2004;36:95-106. 9. Bakas T, Champion V, Perkins SM, Farran CJ, Williams LS. Psychometric testing of the revised 15-item Bakas Caregiving Outcomes Scale. Nurs Res 2006;55:346-55. 10. Doan Q, Brashear A, Gillard P, et al. Relationship between disability and health-related quality of life and caregiver burden in patients with upper-limb poststroke spasticity. PM R 2012;4:4-10. 11. Han B, Haley WE. Family caregiving for patients with stroke: review and analysis. Stroke 1999;30:1478-85. 12. Chumbler NR, Rittman M, Van Puymbroek M, Vogel WB, Qin H. The sense of coherence, burden and depressive symptoms in informal caregivers during the first month after stroke. Int J Geriatr Psychiatry 2004;19:944-53. 13. DiBonaventura M, Wagner J, Yuan Y, L’Italien G, Langley P, Ray Kim W. Humanistic and economic impacts of hepatitis C infection in the United States. J Med Econ 2010;13:709-18. 14. Bakas T, Burgener SC. Predictors of emotional distress, general health, and caregiving outcomes in family caregivers of stroke survivors. Top Stroke Rehabil 2002;9:34-45. 15. Kroenke K, Spitzer RL. The PHQ-9: a new depression diagnostic and severity measure. Psychiatr Ann 2002;32:509-21. 16. Ho SC, Chan A, Woo J, Chong P, Sham A. Impact of caregiving on health and quality of life: a comparative population-based study of caregivers for elderly persons and noncaregivers. J Gerontol A Biol Sci Med Sci 2009;64:873-9. 17. Epstein-Lubow G, Davis JD, Miller IW, Tremont G. Persisting burden predicts depressive symptoms in dementia caregivers. J Geriatr Psychiatry Neurol 2008;21:198-203. 18. Rigby H, Gubitz G, Eskes G, et al. Caring for stroke survivors: baseline and 1-year determinants of caregiver burden. Int J Stroke 2009;4:152-8.
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ORIGINAL ARTICLE
Anxiety and Depression Associated With Caregiver Burden in Caregivers of Stroke Survivors With Spasticity Melissa S. Denno, PharmD,a Patrick J. Gillard, PharmD, MS,b Glenn D. Graham, MD,c Marco D. DiBonaventura, PhD,d Amir Goren, PhD,d Sepi F. Varon, PhD,b Richard Zorowitz, MDe From aMercer University College of Pharmacy and Health Sciences, Atlanta, GA; bAllergan, Irvine, CA; cVA Medical Center, Albuquerque, NM; d Health Sciences Practice, Kantar Health, New York, NY; and eDepartment of Physical Medicine and Rehabilitation, Johns Hopkins Bayview Medical Center, Baltimore, MD.
Abstract Objective: To investigate the relationship between anxiety/depression and caregiver burden in informal caregivers of stroke survivors with spasticity. Design: Data were collected via online surveys from informal caregivers 18 years or older who cared for stroke survivors. Setting: Internet-based survey. Participants: 2007 through 2009 U.S. National Health and Wellness Survey database or Lightspeed Research general panel respondents. Interventions: Not applicable. Main Outcome Measures: Anxiety and depression were self-reported by the caregiver as a physician diagnosis. Depression severity was measured by the Patient Health Questionnaire-9 (PHQ-9). Caregiver burden was measured by the Oberst Caregiving Burden Scale (OCBS) and the Bakas Caregiving Outcomes Scale (BCOS). Logistic regression analyses were conducted with anxiety, depression, and the PHQ-9 depression severity categories as a result of each caregiver burden scale. Results: Data were analyzed for 153 informal caregivers; they were mostly women (70.6%) and white (78.4%), with a mean age of 51.6 years. For every 1-point increase in the OCBS Difficulty Scale, the odds of anxiety or depression were 2.57 times as great (P<.001) and 1.88 times as great (PZ.007), respectively. The odds of PHQ-9 severe depression versus all other categories combined were 2.48 times as great (P<.001). For every 1-point decrease in the BCOS, the odds of anxiety or depression were 2.43 times as great (P<.001) and 2.27 times as great (PZ.002), respectively. The odds of PHQ-9 severe depression versus all other categories combined were 4.55 times as great (P<.001). Conclusions: As caregiver burden increases, caregivers are more likely to have anxiety and depression. Depression severity also increases. Providing treatment to stroke survivors with spasticity that lessens the time and more importantly, the difficulty of caregiving may lead to a reduction in caregiver anxiety and depression. Archives of Physical Medicine and Rehabilitation 2013;-:------ª 2013 by the American Congress of Rehabilitation Medicine
Stroke is the third leading cause of death and a leading cause of long-term disability in the United States.1 Of the estimated 5.7 million stroke survivors in the United States, approximately 19% to Presented as a poster to the Academy of Managed Care Pharmacy, October 13e15, 2010, St. Louis, MO. No commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a benefit on the authors or on any organization with which the authors are associated (Denno, Gillard, Graham, Varon, Zorowitz). A commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a financial benefit on the author or one or more of the authors. Allergan, Inc, provided funding for the study; DiBonaventura and Goren, as employees of Kantar Health, helped design, execute, and report on the study with funding from Allergan.
38% have spasticity.2,3 Spasticity is a disorder of the sensorimotor system characterized by a velocity-dependent increase in muscle tone with exaggerated tendon jerks that may contribute to disability.4 Stroke survivors with spasticity frequently experience physical disability, secondary limb deformities, and pain that limit their ability to perform basic activities of daily living such as dressing, personal hygiene, and mobility.4,5 As a result, informal caregivers who voluntarily provide care play an important role in the lives and long-term care of stroke survivors with spasticity.6 Informal care of a stroke survivor may involve personal care; assistance with dressing, walking, and activities of daily living; as
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well as emotional and social support.7 Providing this care may result in a burden experienced by the informal caregivers that is not endured by noncaregivers. Caregiver burden is often measured by the amount of time required by the caregiver, difficulty in tasks performed, and lifestyle changes as a result of caregiving.8,9 Doan et al10 reported that the time (hours per week) an informal caregiver spends providing care for a stroke survivor with spasticity increases with increasing disability of the stroke survivor. Multiple studies have recognized that burden caused by caring for a stroke survivor is a detriment to the mental health of the caregiver.11 The literature has shown that stroke caregivers have consistently higher rates of depression (34%e52%) than noncaregiver control groups.11 Increased rates of depression may be due to factors such as the physical disability of the patient, decreased social activity of the caregiver, and level of dependency of the patient, among others.11 There is also evidence suggesting that declining caregiver health is associated more with the difficulty in providing care than the time required,8 and that caregivers of patients with less functional independence report more depressive symptoms.8,12 The aim of this study was to examine the relationship between anxiety and depression and caregiver burden among informal caregivers of stroke survivors with spasticity, an area not previously studied.
Methods Study design Data for this study were obtained through a cross-sectional internet survey (approximately 25min in length) fielded to members of an online panel who identified themselves as living in a household with a stroke survivor or caring for a stroke survivor. The study was approved by the Essex Institutional Review Board in Lebanon, New Jersey.
Study population The caregiver population for this study was obtained through the Lightspeed Research (LSR) panel respondents who were a part of the U.S. National Health and Wellness Survey (NHWS) in 2007, 2008, or 2009, and the LSR panelists at large. The NHWS is an annual cross-sectional study of subjects 18 years or older with the goal of providing “a comprehensive database of epidemiologic and treatment information, healthcare attitudes, behaviors, demographic and disease characteristics, and healthrelated outcomes.”13(p710) The LSR is a panel of more than 3.4 million respondents in 24 countries who are recruited by an optin e-mail, coregistration with LSR partners, e-newsletter campaigns, banner placements, and both internal and external affiliate networks. In order to become a panel member of the
List of abbreviations: BCOS CI LSR MS NHWS OCBS PHQ-9
Bakas Caregiving Outcomes Scale confidence interval Lightspeed Research multiple sclerosis National Health and Wellness Survey Oberst Caregiving Burden Scale Patient Health Questionnaire-9
LSR, the potential panelist must register with a unique e-mail address and password and complete an in-depth demographic registration profile. In 2007, 2008, and 2009, the NHWS was completed by 63,012, 63,000, and 75,000 members of the LSR panel, respectively. A total of 6978 respondents in either the 2007 through 2009 NHWS databases or in the LSR general panel identified themselves as providing care for a stroke survivor or patient with multiple sclerosis (MS). Although data were collected for MS caregivers, they were not a part of the scope of this article. These individuals were sent an e-mail invitation to participate in the study, which contained a link to the survey website. An e-mail reminder was sent to nonresponders 2 to 4 days after the initial invitation to remind the potential participants to complete the survey. A total of 1599 individuals responded (a 22.9% response rate), 305 (19.1%) met all inclusion criteria, and 153 (9.6%) were caregivers of stroke survivors with spasticity. Inclusion criteria were as follows: (1) 18 years or older; (2) providing care for a stroke survivor or patient with MS; (3) providing care for a patient who has spasticity (assessed by self-reported observation of spasticity [characterized by stiffness, tone, tightness, muscle resistance, pain, and contracture, as specified within the survey]); (4) providing care for at least 6 months; and (5) not self-employed or employed by an agency as a caregiver. Any formal or paid caregivers were excluded from this study and were not sent survey information. Respondents who completed the survey received points that could be accumulated and exchanged for small prizes through LSR. Data were retained for respondents who completed the survey; questions could not be skipped, except for sensitive questions such as weight and height and others with explicit “don’t know” response options.
Outcome measures Oberst Caregiving Burden Scale The Oberst Caregiving Burden Scale (OCBS) is a reliable and valid 15-item questionnaire that rates 15 different types of caregiving tasks for stroke survivors based on perceived time (OCBS-Time) and difficulty (OCBS-Difficulty) of the task.14 Each item is scored on a 5-point response scale. In response to time for each item, the caregiver chooses an amount ranging from no time (score, 1) to a great deal of time (score, 5) spent on tasks related to caregiving. In response to difficulty for each item, the caregiver chooses an amount ranging from not difficult (score, 1) to extremely difficult (score, 5). Scores were calculated by averaging across the 15 items of the time and difficulty subscales, thus achieving an average score between 1 and 5 for each subscale. Summed scores can be obtained by multiplying mean scores by 15 (eg, in order to compare results against other studies using OCBS, with possible range of 15e75), but for present purposes, mean scores were used in order to preserve the interpretability and contiguity of the original item scale scores. Higher scores represent more perceived time or difficulty of the task. Therefore, higher scores indicate increased caregiver burden. Bakas Caregiving Outcomes Scale The Bakas Caregiving Outcomes Scale (BCOS) is a reliable and valid 15-item questionnaire that measures life changes as a consequence of caregiving for a stroke survivor.9 The 15 items are scored on a 7-point scale, with responses ranging from changed for the worse (score, 1) to changed for the best (score, 7) www.archives-pmr.org
Anxiety/depression in spasticity caregivers as a consequence of caring for a stroke survivor. Scores are calculated by averaging across the 15 items, thus achieving an average score between 1 and 7, with lower scores indicating increased caregiver burden.9 Again, means rather than summed scores were used to preserve item interpretability, but can be multiplied by 15 to obtain the full 15 to 105 range. Self-reported anxiety and depression Within the survey, caregivers were asked to select whether they had ever received a diagnosis of various health conditions from a physician. Anxiety and depression were listed as conditions independent of one another. Patient Health Questionnaire-9 The Patient Health Questionnaire-9 (PHQ-9) is a reliable and valid questionnaire for the assessment of depression, derived from the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition.15 The PHQ-9 consists of 9 items, with each item having to do with symptoms of depression over the previous 2 weeks. Item responses range from not at all (0), on several days (1), on more than half the days (2), and nearly every day (3). PHQ-9 Severity Index scores range from 0 to 27 and are calculated by summing across the 9 items. PHQ-9 Severity Index scores can be categorized into level of depression severity: none (0e4), mild (5e9), moderate (10e14), moderately severe (15e19), and severe (20e27).15
Statistical analyses Multiple logistic regressions were run in SPSS 15.0a to predict anxiety and depression as a function of caregiver burden using OCBS-Time, OCBS-Difficulty, and BCOS scores. Ordered logistic regressions were used to predict the relative odds of being in any higher PHQ-9 depression severity category (vs the current category and all lower categories combined) with an increase in caregiver burden (eg, moderately to severely depressed vs none to mildly depressed), in order to assess the adjusted relative odds of clinically intuitive shifts associated with 1-unit changes in burden. Linear regressions were also used to predict PHQ-9 score with an increase in caregiver burden (OCBS-Time, OCBS-Difficulty, or BCOS scales) to complement the logistic regressions with an understanding of the units of change in burden associated with corresponding shifts across depression categories. A P value of less than .05 was considered indicative of statistical significance, and 95% confidence intervals (CIs) were calculated. All regression analyses controlled for age, sex, race, education, employment, annual household income, and caregiver relationship to the patient. These variables were controlled for because of the possible impact they have on caregiver burden and the conditions of anxiety and depression. Controlling for each of these covariates strengthens the observed association between caregiver burden and the conditions of anxiety and depression.
3 Table 1 Demographics of informal caregivers of stroke survivors with spasticity Characteristics
Caregivers (NZ153)
Age (y) Women White Graduated college Employment Employed Retired Homemaker Other Caregiver relationship with patient Daughter/son Spouse/significant other Daughter-/son-in-law Other Income $50,000 <$50,000
51.612.59 108 (70.6) 120 (78.4) 70 (45.8) 75 30 16 32
(49.0) (19.6) (10.5) (20.9)
91 27 14 21
(59.5) (17.7) (9.2) (13.7)
92 (60.1) 61 (39.9)
NOTE. Values are mean SD or n (%).
(78.4%), with a mean age of 51.6 years. The caregiver was most commonly a child of the stroke survivor (59.5%), with 17.7% being a spouse or significant other, and 9.2% being a daughter-inlaw or son-in-law.
Burden and diagnoses The BCOS scale had a Cronbach alpha of .944 for the 15 items, indicating very high reliability. The OCBS Time and Difficulty subscales had Cronbach alpha values of .913 and .938, respectively, also indicating high reliability. Caregiver burden scores for the informal caregivers of stroke survivors with spasticity are reported in table 2. The mean scores SD for OCBS-Time, OCBS-Difficulty, and BCOS were 3.08.86, 2.16.90, and 3.28.87, respectively. Of the 153 caregivers, 33 respondents (21.6%) reported that they had a physician diagnosis of anxiety, and 34 (22.2%) reported a physician diagnosis of depression. PHQ-9 categories of depression included none (44.4%), mild (19.6%), moderate (18.3%), moderately severe (10.5%), and severe (7.2%).
Demographics
OCBS-Difficulty as a predictor of anxiety, depression, and depression severity The OCBS-Difficulty score was a statistically significant predictor of anxiety, depression, and of being in any higher depression severity category as measured by the PHQ-9. For every 1-point increase in the OCBS-Difficulty score, the odds of a diagnosis of anxiety or depression were 2.57 times greater (95% CI, 1.57e 4.21; P<.001) and 1.88 times greater (95% CI, 1.19e2.99; PZ.007), respectively. The odds of being in any higher depression severity category (eg, any depression category vs no depression) were 2.48 times greater (95% CI, 1.72e3.56; P<.001) (fig 1).
The mean age, sex, race, college experience, employment status, caregiver relationship to patient, and income of the informal caregivers of stroke survivors with spasticity are listed in table 1. Most of the caregivers (NZ153) were women (70.6%) and white
OCBS-Time as a predictor of anxiety, depression, and depression severity The odds of anxiety and depression did not differ significantly with changes in the OCBS-Time score (P>.35). However, the
Results
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4
M.S. Denno et al Table 2 Caregiver burden of informal caregivers of stroke survivors with spasticity Measures of Caregiver Burden Caregiving burden OCBS-Time* OCBS-Difficulty* BCOSy Self-reported anxiety Self-reported depression PHQ-9 None Mild Moderate Moderately severe Severe
Respondents (NZ153) 3.08.86 2.16.90 3.28.87 33 (21.6) 34 (22.2) 68 30 28 16 11
(44.4) (19.6) (18.3) (10.5) (7.2)
NOTE. Values are mean SD or n (%). * Scores are between 1 and 5, with higher numbers indicating increased caregiver burden. y Scores are between 1 and 7, with lower numbers indicating increased caregiver burden.
odds of being in any higher depression severity category as measured by the PHQ-9 were 1.96 times greater with a 1-point increase in the OCBS-Time score (95% CI, 1.35e2.83; P<.001) (see fig 1). BCOS as a predictor of anxiety, depression, and depression severity The BCOS score, measured via responses regarding life changes, was also a statistically significant predictor of anxiety, depression, and of being in any higher depression severity category as measured by the PHQ-9. For every 1-point decrease in the BCOS, the odds of a diagnosis of anxiety or depression were 2.43 times greater (95% CI, 1.47e4.16; PZ.001) and 2.27 times greater
Fig 2 Odds ratio* (95% CI, P value) for anxiety, depression, or higher PHQ-9 categorical severity with each 1-point decrease in BCOS score. *Logistic regression model predicting odds of anxiety, depression, and higher PHQ-9 severity category based on BCOS score. Each value represents a separate regression model, predicting the outcome variable as a function of the caregiver burden variables, adjusted for age, sex, white (vs other race/ethnicity), graduated college (vs not), employed (vs not), income $50,000 (vs less), and caring for spouse or significant other (vs caring for others).
(95% CI, 1.35e3.70; PZ.002), respectively. The odds of being in any higher depression severity category were 4.55 times greater (95% CI, 2.94e7.14; P<.001) (fig 2). Caregiver burden scores as predictors of depression severity (linear regression) Figure 3 represents a change in depression severity as measured by the PHQ-9 as a function of each caregiver burden score. Based on linear regression, an increase of 2.44 points in the OCBS-Time score predicts a shift into the next-higher depression severity category (bZ2.05; 95% CI, .92e3.18; P<.001). An increase of 1.78 points in the OCBS-Difficulty score or a decrease of 1.31 points in the BCOS “life changes” score also predicts a shift into the next-higher depression severity category (bZ2.80; 95% CI, 1.76e3.85; P<.001).
Discussion
Fig 1 Odds ratio* (95% CI, P value) for anxiety, depression, or higher PHQ-9 categorical severity with each 1-point increase in OCBSTime or OCBS-Difficulty score. *Logistic regression model predicting odds of anxiety, depression, and higher PHQ-9 severity category based on OCBS-Time and OCBSDifficulty scores. Each value represents a separate regression model, predicting the outcome variable as a function of the caregiver burden variables, adjusted for age, sex, white (vs other race/ethnicity), graduated college (vs not), employed (vs not), income $50,000 (vs less), and caring for spouse or significant other (vs caring for others).
Increased caregiver burden was associated with significantly poorer mental health of informal caregivers of stroke survivors with spasticity. As caregiver burden increases, it is more likely that caregivers may have anxiety and depression. The difficulty of completing tasks associated with caregiving appears to be a stronger predictor of anxiety and depression than the time required to complete such tasks. Increases in the difficulty of tasks and in the time required for caregiving have both been shown to be associated with an increase in depression severity. Studies in several diseases show that the odds of caregiver depression and anxiety increase with an increase in caregiver burden. In a population of caregivers of patients with dementia, for example, each incremental increase in caregiver burden score was associated with a 60% to 70% increase in the risk of reporting anxiety and depression.16 Similarly, in a study by Epstein-Lubow et al,17 caregivers of patients with dementia who had persisting www.archives-pmr.org
Anxiety/depression in spasticity caregivers
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Fig 3 PHQ-9 scores predicted by each caregiver burden scale. BCOS scores >5 were excluded from the figure because only 3 individuals had scores in that range.
high caregiver burden showed significantly worsened depression survey scores 12 months into the study, when compared with caregivers without persisting high caregiver burden (PZ.029). The results of our study confirm and quantify this positive relationship between caregiver burden and the likelihood of anxiety and depression in caregivers of stroke survivors with spasticity. Consistent with previous studies mentioned, our findings demonstrated that caregiver burden, in this case quantified by the OCBS-Difficulty and BCOS “life changes” validated scales, was associated with significantly increased odds of reporting anxiety, depression, and being in a higher PHQ-9 depression severity category. Moreover, our results were comparable in magnitude to other study results that indicated increased anxiety and depression as an outcome of caregiver burden in caregivers of other disease states. We also evaluated the similarity between our population and the overall stroke populations included in other studies. In 2 studies,8,14 both time and difficulty in completing tasks were predictors of “emotional distress” (mood) and negative caregiver outcomes (measured as change in social functioning, subjective well-being, and physical health as a result of providing care) in caregivers of stroke survivors. Additionally, the difficulty subscale score was a significant independent predictor of “emotional distress” and caregiver outcomes.14 Similar findings showed that the tasks perceived as most time-consuming and most difficult were significant predictors of negative mood of the caregiver.8 Multiple tasks dealing with difficulty were independent predictors of negative caregiver mood, while only 1 task dealing with time (managing finances, bills, and forms) was an independent predictor. Only the tasks shown to be most difficult were predictors of negative caregiver outcomes.8 The results of these studies confirm our findings by demonstrating an association of both time and difficulty of tasks with anxiety and depression. We also found a stronger association between development of these psychological outcomes and the difficulty of completing tasks. Both physical disability, measured by the Barthel Index, and self-reported dependency have been found to be predictors of caregiver burden in previous studies.18 It may be possible that increased physical disability translates to www.archives-pmr.org
more difficulty associated with completing tasks, contributing to heightened caregiver burden.
Study limitations There are several limitations to this study. The study was observational and cross-sectional. Therefore, causal effects of caregiver burden on anxiety and depression could not be definitively distinguished from reverse causal effects of depression on caregiver burden. The utilization of an online survey and the low overall response rate (ie, a subset of a subgroup of respondents originally identified as caregivers for persons with stroke or MS) limit the generalizability of the results, given the possible overrepresentation of respondents with particular characteristics (eg, being relatively young and mobile, or those having access to a computer). Although potential confounding variables were controlled for in the study, it is possible that other unrecognized confounders may be present. For instance, we did not control for severity of stroke within our study. This study also does not compare outcomes for caregivers of stroke survivors with spasticity with those for patients without spasticity, so the incremental impact of spasticity on caregiver burden cannot be determined. The outcomes within this study can only be attributed to caregivers of stroke survivors with spasticity as a whole. Furthermore, the study does not allow us to determine whether physical attributes (as expected with post-stroke spasticity per se) or cognitive attributes (as generally expected with brain injury) account for most of the association with outcomes. Self-report measures used in the study, such as diagnosis with depression and anxiety, are subject to potential biases and lack of validation against clinical measures such as patient charts. There is also the possibility that caregivers without internet access may respond differently to caregiver burden than those caregivers able to use internet resources. Caregivers who were unwilling or unable to complete the entire survey (and whose data were therefore excluded from consideration) may also have differed in terms of their characteristics and motivations from those who participated fully. These caregivers would not have
6 been captured in this study. The OCBS and BCOS caregiver burden scales have also not been specifically validated in caregivers of stroke survivors with spasticity, although they have been validated in stroke survivors. Lastly, anxiety and depression were determined through caregiver self-report of physician diagnoses; thus the conditions could have been under- or overreported, based on caregiver perceptions of their diagnoses.
Conclusions Increased caregiver burden was associated with significantly poorer mental health of informal caregivers of stroke survivors with spasticity. As caregiver burden increases, caregivers are more likely to have anxiety and depression. The severity of depression may also increase. Further evaluation of the clinical significance and implications for caregiver lifestyle of the increased anxiety and depression resulting from caregiver burden, as well as a comparison of the burden on caregivers of stroke survivors with and without spasticity, is warranted. An understanding of these relationships will not only lead to a better understanding of the impact of caregiver burden, but it may also provide insight into which interventions will be most effective in reducing anxiety and depression in caregivers of stroke survivors with spasticity. While not evaluated in this study, treatment options that decrease the time, and more importantly, the difficulty of caring for a stroke survivor with spasticity may lead to a reduction in caregiver anxiety and depression. Treatment options that reduce the functional disability of the stroke survivor caused by spasticity may also translate to reduced time and difficulty of tasks completed by the caregiver. Further study is warranted.
Supplier a. IBM Corp, 1 New Orchard Rd, Armonk, NY 10504-1722.
Keywords Anxiety; Caregivers; Depression; Muscle spasticity; Rehabilitation; Stroke
Corresponding author Melissa S. Denno, PharmD, 4114 Woodlands Pkwy, Ste 500, Palm Harbor, FL 34685. E-mail address: [email protected].
M.S. Denno et al
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