C International Psychogeriatric Association 2014 International Psychogeriatrics (2014), 26:8, 1273–1282  doi:10.1017/S1041610214000660

Differential perceptions of quality of life (QoL) in community-dwelling persons with mild-to-moderate dementia ...........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................

Laura Tay,1,2 Kia Chong Chua,3 Mark Chan,1,2 Wee Shiong Lim,1,2 Yue Ying Ang,1 Evonne Koh4 and Mei Sian Chong1,2 1

Department of Geriatric Medicine, Tan Tock Seng Hospital, Singapore Institute of Geriatrics and Active Ageing, Tan Tock Seng Hospital, Singapore 3 Institute of Psychiatry, King’s College London, London, UK 4 Yong Loo Lin School of Medicine, National University of Singapore, Singapore 2

ABSTRACT

Background: Discordance between patient- and caregiver-reported quality of life (QoL) is well recognized. This study sought to (i) identify predictors of discrepancy between patient- and caregiver-rated QoL amongst community-dwelling persons with mild-to-moderate dementia, and (ii) differentiate between patients who systematically rate their QoL lower versus those who rate their QoL higher relative to their caregiver ratings. Methods: We recruited 165 patient–caregiver dyads with mild-to-moderate dementia. Quality of life in Alzheimer’s disease (QoL-AD) scale was administered separately to patients and caregivers. Data on sociodemographics, interpersonal relationship, and disease-related characteristics (cognitive performance, mood, neuropsychiatric symptoms, functional ability, and caregiver burden) were collected. Patient–caregiver dyads were categorized based on whether patient-rated QoL was lower or higher than their respective caregiver ratings. Univariate analyses and multiple regression models were performed to identify predictors of dyadic rating discrepancy. Results: Mean patient-rated QoL was significantly higher than caregiver rating (mean difference: 3.8 ± 7.1, p < 0.001). Majority (111 (67.2%)) of patients had more positive self-perceived QoL (QoL-ADp (QoL-AD self rated by the patient) > QoL-ADc (QoL-AD proxy-rated by a caregiver)), compared with those (44 (26.7%)) with poorer self-perceived QoL (QoL-ADp < QoL-ADc). Patient’s education level, depressive symptoms, and severity of neuropsychiatric symptoms predicted magnitude of discrepancy. Depression (OR = 1.17, 95% CI = 1.02–1.35) and being cared for by other relative (non-spouse/adult child; OR = 7.54, 95% CI = 1.07–53.03) predicted poorer self-perceived QoL. Conclusions: Dyadic rating discrepancy in QoL should draw the clinician’s attention to patient depression and neuropsychiatric symptoms. Consideration should also be given to nature of patient–caregiver relationship when discordance between patient and caregiver assessments of QoL is observed. Key words: quality of life, dementia, caregivers, agreement

Introduction Dementia is a chronic debilitating condition that exacts a profound negative impact on patients and their caregivers, consequent to deteriorating intellectual and physical functioning (Feldman et al., 2005). Enhancing and maintaining quality of life (QoL) in persons with dementia is thus a major

Correspondence should be addressed to: Dr Laura Tay, Department of Geriatric Medicine, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. Phone: +65-6357-7859; Fax: +65-6357-7837. Email: [email protected] Received 27 Dec 2013; revision requested 24 Jan 2014; revised version received 3 Mar 2014; accepted 14 Mar 2014. First published online 23 April 2014.

priority in dementia care. Indeed, the International Working Group for Harmonization of Dementia Drug Guidelines and the Alzheimer’s Society recommend that consideration be given to QoL from the perspectives of patients, family caregivers, and professionals when evaluating the efficacy and appropriateness of therapeutic interventions (Mack and Whitehouse, 2001). The growing emphasis on QoL as a treatment goal in dementia care necessitates its accurate assessment, to facilitate care providers in tailoring effective interventions to improve the well-being of persons with dementia. QoL is generally accepted as a multi-dimensional construct extending beyond subjective perception to include objective domains such as behavior

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and functional abilities (Lawton, 1994). While there is still no consensus regarding the procedure for assessment of QoL in dementia, there is cumulative evidence that persons with mild-tomoderate dementia can reliably rate their own QoL (Brod et al., 1999; Logsdon et al., 2002). Patient-rated QOL emphasizes the individual’s subjectively appraised experiences and has been lauded for respecting the autonomy of the person with dementia (Buckley et al., 2012). However, clinicians often become increasingly reliant on caregivers as the primary source of information with deteriorating cognitive function in patients. Unfortunately, significant discordance exists between patient- and caregiver-rated QoL, with tendency for underestimation when rated by caregivers (Logsdon et al., 2002; Conde-Sala et al., 2009; Huang et al., 2009). This discrepancy has also been interpreted to reflect the unique and independent perspectives of QoL between persons with dementia and their caregivers (Naglie, 2007). There is substantive literature reporting the separate perceptions of dementia patient’s QoL, as rated by persons with dementia and their caregivers, with factors such as cognition, behavior, and functional ability having been variably associated with either patient or caregiver perspectives (CondeSala et al., 2009; Hurt et al., 2010; Sousa et al., 2013). Recognizing the often poor correlations between patient and caregiver ratings, recent studies sought to explore predictors for the discrepancies between patient’s and caregiver’s perceptions of QoL, incorporating patient characteristics such as loss of insight into their impairment and behavioral disturbances, caregiver factors including perceived burden of care, as well as nature of the caregiver–patient relationship (Huang et al., 2009; Zhao et al., 2012; Conde-Sala et al., 2014). However, these studies focused on magnitude of discrepancy and caregiver rating bias toward underestimation, without differentiating between patients who systematically rate their QoL lower relative to their caregiver ratings from counterparts who rate their QoL higher than their caregivers. Addressing how, in addition to why patient and caregiver ratings of QoL may be disparate, will further guide clinicians in assessment of well-being of persons with dementia and inform clinical decision making. The objectives of this study were to (i) identify predictors of discrepancy between patient- and caregiver-rated QoL amongst community-dwelling persons with mild-to-moderate dementia, and (ii) differentiate between patients who systematically rate their QoL lower versus those who rate their QoL higher relative to their caregiver ratings, exploring the factors predictive of a poorer selfperceived QoL.

Methods Study population We recruited 165 mild-to-moderate communitydwelling dementia patient–caregiver dyads attending the Memory Clinic in Tan Tock Seng Hospital, Singapore, from June 2011 to September 2012. We included patients aged ࣙ55 years who met Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) criteria for dementia with a Clinical Dementia Rating (CDR) global score of >0 and ࣘ2, indicating the dementia to be of mild-to-moderate severity (Morris, 1993; Lim et al., 2005). They had to be accompanied by a reliable caregiver or informant and be fluent in either English or Mandarin. The caregiver or informant had to be the primary caregiver of the patient and be ࣙ21 years of age. We excluded dementia patients with a CDR score of ࣙ3 (severe dementia) or 0 (no dementia) and patients with no reliable informant or caregiver. We also excluded patients with mild cognitive impairment and those living in an assisted living facility or nursing home. Patient–caregiver dyads fulfilling inclusion/exclusion criteria were invited to participate in the study by their attending geriatrician. Verbal assent to study participation was obtained from the patients, with written informed consent from the caregivers. Ethics approval was obtained from the National Healthcare Group Domain-Specific Review Board.

Measures QUALITY OF LIFE IN ALZHEIMER’S DISEASE SCALE

The dementia-specific QoL-AD (Logsdon et al., 2002), designed to be self-rated by the cognitively impaired person (QoL-ADp) and proxy-rated by a caregiver (QoL-ADc), was administered separately in interview format to both patient and caregiver. The 13 items in QoL-AD reflect multiple domains of subjective health, with each item being rated on a 4-point Likert scale: 1 = poor, 2 = fair, 3 = good, and 4 = excellent. An overall score was calculated separately for the patient and caregiver reports by summing the 13 items (range 13 to 52), with higher scores indicating higher QoL. We also computed a composite QoL score that took into account ratings by both patient and caregiver, but with higher weighting given to patient’s rating (patient-rated QoL-AD is multiplied by 2 before being added to the caregiver-rated QoL-AD, and the sum is divided by 3; Zhao et al., 2012). Good reliability and validity of patient and caregiver reports on QoL-AD have been established (Logsdon et al., 2002).

Differential QoL perceptions in dementia QOL Patient and caregiver socio-demographics: We collected

CORRELATES OF

socio-demographic data including age, gender, ethnicity, and level of education of patients and caregivers. Information on caregiver employment status was routinely documented. Inter-personal relationship: Indicators of interpersonal relationship included nature of caregiver’s relationship with the patient, level of caregiver’s contribution to patient’s care and caregiver’s living arrangement with the patient. Disease-related scales: Cognitive status was assessed using the Chinese Mini-Mental State Examination (CMMSE, range 0 to 28; Sahadevan et al., 2000). Functional ability was evaluated on the Bristol Activities of Daily Living Scale (Bristol ADL), a carer-rated instrument consisting of 20 daily-living abilities (range 0 to 60, higher scores indicating greater dependency; Bucks et al., 1996). Psychological and behavioral evaluation was performed via the Cornell Scale for Depression in Dementia (CSDD; Alexopoulos et al., 1988), as well as the 12-item informantbased Neuropsychiatric Inventory Questionnaire (NPI-Q; Kaufer et al., 2000), which assessed symptom severity (summated to yield a total NPIQ severity score, ranging from 0 to 36) as well as caregiver distress associated with each symptom manifestation (total NPI-Q distress score ranging from 0 to 60). We used the CDR, a structured clinician rating, to determine dementia severity. A trained assessor administered the different scales and questionnaires used. Caregiver burden was assessed using the Zarit Burden Interview (ZBI) (Zarit et al., 1980). To further explore the different domains of caregiver burden that may impact on QoL, we used four subscales of the ZBI as identified in our previous study (Cheah et al., 2012): factor 1 – demands of care and societal impact on caregiver (role strain); factor 2 – confidence or control over the situation (role strain); factor 3 – psychological impact on caregiver (personal strain); factor 4 – worry about caregiving performance. Statistical analysis: Descriptive data are presented

as means (±SD) for quantitative variables and as absolute and relative frequencies for qualitative variables. The internal consistency reliability of patient and caregiver ratings of QoL-AD was established using Cronbach’s α. Agreement between patient-rated and caregiverrated QoL-AD scores was examined for both consistency and absolute agreement, using a two-way mixed model, single-measure intraclass correlation coefficient (ICC). Student t-test for paired data

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was used to evaluate the difference between QoLADp and QoL-ADc scores. Discrepancy score for each patient–caregiver dyad was calculated by subtracting caregiver-rated QoL from the respective patient-rated QoL (discrepancy score greater than zero indicating that QoL was underestimated by caregiver relative to patient rating). To identify predictors of discrepancy between patient- and caregiver-rated QoL, the discrepancy score was entered as the dependent variable in generalized linear regression analyses. The predictor variables examined included patient and caregiver demographics (age, gender, education), diseaserelated characteristics (cognitive performance, dementia severity, behavioral and psychological symptoms (NPI-Q total severity score and CSDD), Bristol ADL, and caregiver burden), and inter-personal relationship (patient–caregiver relationship and caregiver’s level of contribution to patient’s care). Predictors with a significance level QoL-ADc) in demographic variables, disease-related characteristics, and interpersonal relationship. We performed multiple logistic regression using variables with p < 0.10 in univariate analyses with adjustment for patient and caregiver age and gender, to determine factors for patient’s poorer self-perceived QoL relative to their caregiver’s rating. Statistical analyses were performed using the SPSS software (version 19.0). All statistical tests were two-tailed, with p value ࣘ0.05 considered statistically significant.

Results Socio-demographic and disease-related characteristics (Table 1) 165 dementia patient–caregiver dyads were studied. All patients were able to rate their own QoLAD. The mean age of patients was 76.8 ± 6.9 years, approximately half (55.2%) were women, and majority (95.2%) were living with their spouses and/or children. 127 patients had mild dementia (CDR: 0.5–1) and 38 had moderate dementia (CDR: 2). Mean CMMSE score of the patient cohort was 18.4 ± 4.2 and mean Bristol ADL score was 15.2 ± 9.1. The mean total NPI-Q

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Table 1. Characteristics of 165 patient–caregiver dyads CHARACTERISTICS

PATIENT

CAREGIVER

.........................................................................................................................................................................................................................................................................................................................

Socio-demographics Age, years (mean ± SD) Gender (female %) Ethnicity (Chinese %) Education, years (mean ± SD) Actively employed currently Yes (%) No (%) Interpersonal relationship Nature of relationship Spouse (%) Adult child (%) Other relative (%) Living with patient Yes (%) No (%) Level of contribution to patient’s care compared with all other caregivers involved (%) Disease-related characteristics Dementia severity Global CDR (mean ± SD) Cognitive status CMMSE (mean ± SD) Functional status Bristol ADL (mean ± SD) Depression CSDD (mean ± SD) Behavioral symptoms NPI-Q total severity (mean ± SD) Caregiver burden Zarit caregiver burden (mean ± SD)

76.8 (6.9) 55.2 90.9 7.2 (4.5)

58.1 (13.5) 64.2 – 11.4 (3.7)

– –

46.7 53.3

– – –

37.0 56.4 6.6

– – –

70.3 29.7 58.2

1.2 (0.5)



18.4 (4.2)



15.2 (9.1)



3.2 (3.9)



3.8 (4.1)





25.9 (15.7)

CMMSE = Chinese Mini-Mental State Examination; CDR = Clinical Dementia Rating; CSDD = Cornell scale for depression in dementia; Bristol ADL = Bristol Activities of Daily Living scale; NPI-Q = Neuropsychiatric Inventory Questionnaire.

severity score was 3.8 ± 4.1. 26 patient–caregiver dyads declined study participation. There was no difference in patient age, gender, and CMMSE between participating and non-participating dyads. Caregivers were predominantly women (64.2%), middle-aged (mean age: 58.1 ± 13.5 years), and spouse (37.0%) or adult child (56.4%) of the person with dementia. 116 caregivers (70.3%) were living with the patient, and average contribution to patient care by the primary caregiver compared with other informal carers involved was 58.2%. Mean Zarit burden score was 25.9 ± 15.7. Reliability and agreement between patientand caregiver-rated QoL-AD The internal consistency of patient and caregiver reports on QoL-AD was good (Cronbach’s α = 0.85 and 0.81, respectively).

There was poor overall agreement between patient- and caregiver-rated QoL-AD, with low ICC values in both absolute agreement (ICC = 0.22, 95% CI = 0.06–0.38) and consistency (ICC = 0.27, 95% CI = 0.12–0.41). Only ten (6.1%) patient–caregiver dyads achieved equivalent QoL ratings (QoL-ADp = QoL-ADc). Patient-rated QoL was lower than the rating provided by the caregiver (QoLADp < QoL-ADc) in 44 (26.7%) dyads, and higher than caregiver-rated QoL (QoL-ADp > QoL-ADc) in 111 (67.2%) dyads. In subgroup analysis, there were moderate-to-good consistency, but moderate-to-poor absolute agreement between patient and proxy ratings (ICC, consistency = 0.78, 95% CI = 0.62–0.87 for QoL-ADp < QoL-ADc dyads; ICC, consistency = 0.55, 95% CI = 0.40–0.66 for QoL-ADp > QoL-ADc dyads (Table 2)).

Differential QoL perceptions in dementia

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Table 2. Agreement between patient and caregiver perceptions of QoL PATIENT- VERSUS CAREGIVER-RATED QOL PATIENT-RATING




PATIENT-RATING

OVERALL COHORT

CAREGIVER RATING

CAREGIVER RATING

(N = 165)

(N = 44)

(N = 111)

.........................................................................................................................................................................................................................................................................................................................

ICC, consistency (95% CI) ICC, absolute agreement (95% CI)

0.27 (0.12–0.41) 0.22 (0.06–0.38)

0.78 (0.62–0.87) 0.52 (−0.09–0.81)

0.55 (0.40–0.66) 0.27 (−0.10–0.57)

QoL = quality of life; ICC = intraclass correlation coefficient.

Table 3. Predictors of discrepancy between patient- and caregiver-rated QoL-AD (n = 165) UNIVARIATE

MULTIPLE LINEAR REGRESSION

ANALYSIS

ANALYSIS MODEL

PREDICTOR

β

p VALUE

β

1a

p VALUE

FI N A L M O D E L

β

a

p VALUE

.........................................................................................................................................................................................................................................................................................................................

Socio-demographics Age of patient Age of caregiver Patient’s gender (vs. male) Caregiver’s gender (vs. male) Patient’s education Caregiver’s education Caregiver’s employment status (vs. unemployed) Interpersonal relationship Caregiver’s relationship (vs. spouse) Level of contribution to care Caregiver staying with patient Disease-related characteristics CMMSE CDR global CSDD NPI-Q total severity score Bristol ADL Zarit caregiver burden

0.02 0.06 − 0.75 1.07 0.94 0.15 − 1.59

0.81 0.17 0.51 0.36 0.01 0.68 0.16

− 1.96 0.03 0.43

0.04 0.05 0.73

0.07 0.22 − 0.25 0.58 0.09 0.07

0.63 0.85 0.09

Differential perceptions of quality of life (QoL) in community-dwelling persons with mild-to-moderate dementia.

Discordance between patient- and caregiver-reported quality of life (QoL) is well recognized. This study sought to (i) identify predictors of discrepa...
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