Assessing quality of life of older people with dementia in long-term care: a comparison of two self-report measures

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1 ORIGINAL ARTICLE Assessing quality of life of older people with dementia in long-term care: a comparison of two self-report measures Wendy Moyle, Natalie Gracia, Jenny E Murfield, Susan G Griffiths and Lorraine Venturato Aims and objectives. This study sought to compare two well-known and well-used self-report quality of life questionnaires in terms of completion rates, reliability and assessment of quality of life. Background. People with dementia have a meaningful experience of quality of life and several disease-specific instruments have been designed to capture self-report assessments. Design. A quantitative survey design, with a convenience sample of older people with dementia from four long-term care facilities. Method. Sixty-one participants were recruited for survey on the Dementia Quality of Life questionnaire and the Quality of Life in Alzheimer s Disease questionnaire. Results. The Quality of Life in Alzheimer s Disease questionnaire had a higher rate of completion (98Æ4%) than the Dementia Quality of Life questionnaire (68Æ9%). Those unable to complete the latter measure had significantly greater cognitive impairment (F 1,59 =30Æ35, p < 0Æ001) than those completing the measure. Internal reliability was good for the Quality of Life in Alzheimer s Disease questionnaire (0Æ86), but there were varying levels found for the five Dementia Quality of Life questionnaire subscales (0Æ79 0Æ48). The Quality of Life in Alzheimer s Disease questionnaire was significantly correlated with all the Dementia Quality of Life questionnaire subscales and overall item. Conclusions. Although it is recognised that there is no superior instrument in assessing quality of life, this study found both the Quality of Life in Alzheimer s Disease questionnaire and Dementia Quality of Life questionnaire to be useful self-report instruments. Relevance to clinical practice. Assessment of quality of life should include the perspective of the person with dementia. The Quality of Life in Alzheimer s Disease questionnaire and Dementia Quality of Life questionnaire appear to measure similar aspects of quality of life. Where assessments are sought from participants with more advanced cognitive and functional impairment, it may be favourable to employ the Quality of Life in Alzheimer s Disease questionnaire. Key words: assessment, dementia, older people, quality of life, questionnaire, survey Accepted for publication: 2 December 2010 Authors: Wendy Moyle, PhD, MHSc, BN, RN, Professor and Director (RCCCPI), Griffith Health Institute, Research Centre for Clinical and Community Practice Innovation, Griffith University; Natalie Gracia, B BehSc/BCCJ, B Psy, Research Assistant, Griffith Health Institute, Research Centre for Clinical and Community Practice Innovation, Griffith University; Jenny E Murfield, BSc, Research Development Coordinator, Griffith Health Institute, Research Centre for Clinical and Community Practice Innovation, Griffith University; Susan G Griffiths, BA, Senior Research Assistant, Griffith Health Institute, Research Centre for Clinical and Community Practice Innovation, Griffith University; Lorraine Venturato, PhD, MN, BN, RN, Research Fellow, RSL Care and Griffith Health Institute, Research Centre for Clinical and Community Practice Innovation, Griffith University, Nathan, Qld, Australia Correspondence: Professor Wendy Moyle, Professor and Director (RCCCPI), Research Centre for Clinical and Community Practice Innovation. Griffith Health Institute, Griffith University, Nathan, Qld, 4111, Australia. Telephone: w.moyle@griffith.edu.au Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing 1 doi: /j x

2 W Moyle et al. Introduction Health service research, including that into dementia and long-term care (LTC) specifically, has undergone a shift in focus, seeing the emphasis move from how care is delivered, to the affect that care has on patients (Sloane et al. 2005). Alongside this, there has also been a move away from research that predominantly focuses on the biomedical outcomes of dementia in terms of clinical features, pathological basis and treatment options (Hubbard et al. 2003, Moore & Hollett 2003, Nygard 2006, Moyle et al. 2007). Collectively, this has culminated in greater efforts to consider and explore the subjective experience of the person with dementia (Sloane et al. 2005, McCabe 2008) and to have how care affects quality of life (QOL) as a key outcome measure in research (Kane 2001, Thorgrimsen et al. 2003, Sloane et al. 2005, Banerjee et al. 2009). Background Although definitions vary, due partly to a lack of consensus regarding what constitutes QOL (Selai & Trimble 1999, Ready et al. 2004, Walker & Lowenstein 2009), there is an emerging agreement on QOL in the context of cognitive impairment. Lawton s (1983) model has traditionally been the most pervasive conceptualisation of QOL in dementia, encompassing both subjective and objective factors based on four components: behavioural competence; objective environment; psychological well-being; and perceived QOL (Lawton 1994). Although many academics support the conceptualisation of QOL as comprising subjective components, the question of whether people with dementia are able to communicate reliably a subjective account of their QOL remains a contentious issue (Thorgrimsen et al. 2003). For example, the very nature of dementia means that cognitive deficits in memory, attention, language and insight may impact on the individual s ability to comprehend and coherently communicate their subjective state (Rabins & Black 2007). In addition, personality changes, depression, agitation and psychosis common to dementia may also encumber attempts to measure QOL (Ready et al. 2004). Such perceived challenges have traditionally led to the assumption that people with dementia are unable to give reliable and valid accounts of their own QOL (Cotrell & Schulz 1993), and thus proxy accounts from caregivers and family members have been used instead (Hubbard et al. 2003, Thompson & Kingston 2004). However, proxy measures are not without validity issues (Novella et al. 2001) and, given the very subjective nature of QOL, it is widely acknowledged that the person with dementia may be the best informants (Lawton 1994, Brod et al. 2000, Kane et al. 2003). Indeed, it has been shown that people with mild-tomoderate dementia (Brod et al. 1999, Trigg et al. 2007, Arlt et al. 2008) and, to some extent, those with severe dementia (Thorgrimsen et al. 2003) can reliably report their QOL. In addition, findings also suggest that people with dementia are able to provide reliable comments on their needs (Orrell et al. 2008). In attempting to quantify QOL in dementia, the last few decades have seen a variety of disease-specific instruments developed (Selai & Trimble 1999, Sloane et al. 2005). The Dementia Quality of Life questionnaire (DQOL) (Brod et al. 1999) and the Quality of Life in Alzheimer s Disease questionnaire (QOL-AD) (Logsdon et al. 1999, 2002) are two such self-report instruments that measure QOL from the perspective of the person with dementia. The QOL-AD, which has been touted as the most widely used self-report measure internationally (Whitehouse et al. 2003), was based on a literature review of QOL in older people and chronically ill populations. Originally a 13-item questionnaire for community-dwelling patients, a modified 15-item version (Edelman et al. 2005) was adapted for use with people in LTC settings. The interviewer-administered measure includes assessment of physical health, mental health, social and financial domains and provides an overall QOL rating in a single score. The DQOL instrument (Brod et al. 1999) was designed through a literature review and focus group consultations with people with dementia, caregivers and professional care providers. There are 29 items, which address five domains of QOL, including self-esteem, positive affect, absence of negative affect, feelings of belonging and sense of aesthetics, and there is a final item that provides an optional global measure of QOL. All items are interviewer administered and there are three screening questions to ensure that participants understand the scale and question format. In exploring the psychometric robustness of the two scales in measuring QOL in older people with dementia, both the DQOL and QOL-AD have been repeatedly shown to be valid and reliable instruments. Specifically, the QOL-AD has been found to have an internal reliability of 0Æ94 (Edelman et al. 2005) and a one-week test retest reliability coefficient of 0Æ76 (Logsdon et al. 1999). Acceptable internal reliability for the DQOL s five scales has also been reported, ranging from 0Æ59 0Æ89 (Sloane et al. 2005). Similarly acceptable twoweek test retest reliability coefficients have also been found for the five subscales of the DQOL, ranging from 0Æ64 0Æ90 (Brod et al. 1999). In terms of the usefulness, appropriateness and actual experience of using the DQOL and QOL-AD, several studies have also provided comment, and these have 2 Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing

3 Original article chiefly been more favourable of the QOL-AD as an instrument for use with older people with dementia. For instance, Selwood et al. (2005) found that in a sample of older people with dementia with an average Mini Mental State Exam (MMSE) score of 10, more participants were able to complete the QOL-AD than the DQOL (73% compared with 60%). Furthermore, although Thorgrimsen et al. (2003) and Hoe et al. (2006) both reported successful use of the QOL-AD with persons with scores as low as 3 on the MMSE, Brooker et al. (2007) were critical of the DQOL in their study. Specifically, due to the large number of participants who had a score of zero on the MMSE (i.e. severe cognitive impairment), only 11 participants completed the DQOL at baseline and follow up. Despite such criticisms, however, the DQOL is still a well-used measure and is regarded as a useful instrument, specifically for those evaluating the impact of daytime activities on QOL of older people with dementia (Scholzel-Dorenbos et al. 2007). This article reports on a comparative analysis of the DQOL and QOL-AD as instruments for use with older people with dementia in LTC facilities. The article is intended to be of practical use for those seeking the views of older people with dementia on their QOL by providing timely insight into how the two, well-known and well-used, scales performed when employed in the same sample of participants in LTC facilities. Specifically, this study sought to compare the DQOL and QOL-AD in the same sample of older people with dementia in LTC in terms of completion rates, reliability and assessment of QOL. Method Design The study was part of a larger programme of research (see Moyle et al. in press), which aimed to provide an understanding of QOL and moral worth of older people with dementia to inform a new model of dementia care. Specifically, the overarching research programme sought to (1) explore QOL and the moral value of older people with dementia living in LTC and to compare their perceptions with family caregivers and care staff; and (2) identify those aspects of the care environment that influence QOL and moral value for the person living with dementia. Using all collected data, the developed model of care draws nursing staff to focus on the capabilities of the person with dementia whilst also providing them with training and education that are strength focused to give clearer roles and solutions to better meet the demands of caring for a person with dementia. This model is currently being trialled in LTC facilities and the results will be reported in future publications. This article focuses on a comparative appraisal of two selfrated dementia-specific measures used to assess QOL of older people with dementia. Data were collected from August December 2007 and involved completion of the DQOL and QOL-AD (both self-report quantitative surveys) with older people with dementia residing in participating LTC facilities. These instruments were chosen because of their reported validity and reliability in studies that have assessed QOL in older people with dementia (Brod et al. 1999, Logsdon et al. 1999, Edelman et al. 2005, Sloane et al. 2005). Ethics approval for the study was received from the University human research ethics committee and a support statement was provided by the partner aged care organisation. Setting Four mixed-gender LTC facilities, providing low (hostel), high (nursing home), special (dementia specific) and respite care, were used to recruit participants. The facilities were managed by a not-for-profit aged care organisation and were located across New South Wales and Queensland, Australia. All were medium-sized, with bed numbers ranging from , and were considered representative of Australian LTC settings. Sample Study participants were recruited from a convenience sample of the four LTC facilities, with managers initially identifying potential male and female participants who met the following four inclusion criteria: (1) a confirmed diagnosis of early to mid-stage dementia, or probable dementia (i.e. a cognitive impairment level of on the MMSE) (Folstein et al. 1975), or features consistent with dementia of Alzheimer s type as per the DSM-IV (American Psychiatric Association 1994); and (2) the ability to complete surveys, with the aide of an assistant; and (3) one family member or friend that was accessible and in contact with the participant; and (4) informed consent provided by next of kin and, where possible, a signature of consent from the participant themselves. The study aimed to recruit 60 people with dementia and recruitment was continued until this number was achieved. Data collection Comparison of the DQOL and QOL-AD Participants were interviewed by trained and experienced Research Assistants (RAs), employed by the University, on two instruments that provided self-report assessments of QOL: Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing 3

4 W Moyle et al. 1 Dementia Quality of Life (DQOL) (Brod et al. 1999): a 29- item questionnaire that has five subscales and an optional final item that can provide an overall assessment of QOL in a single score. The 29 items are rated on one of two fivepoint Likert scales that measure either frequency (ranging from 1 = never 5 = very often ) or enjoyment (1 = not at all 5 = a lot ). Scores for each subscale are calculated by computing the mean score of component items. The optional single item to assess overall QOL is also rated on a five-point scale, ranging from 1 = bad 5 = excellent. Higher scores represent better QOL. 2 Quality of Life Alzheimer s Disease (QOL-AD) (originally devised by Logsdon et al. 1999, 2002, and modified for use in LTC by Edelman et al. 2005): a 15-item questionnaire that provides an assessment of QOL. A four-point Likert scale, ranging from 1 = poor 4 = excellent, is used to rate each item on indicators such as physical health, energy, mood and memory. The measure yields a single mean score ranging from 15 60, with higher scores indicating greater QOL. The final item can also provide an independent assessment of life overall. The person with dementia was also assessed by RAs on the Mini-Mental State Exam (MMSE) (Folstein et al. 1975): a widely used instrument to assess dementia severity. The MMSE provides an overall score ranging from 0 30, with a lower score being indicative of greater cognitive impairment. In addition, an assessment of physical functioning was also undertaken. Trained facility care staff assessed participants on the Physical Self-Maintenance Scale (PSMS) (Lawton & Brody 1969): a six-item scale that provides a functional assessment of basic activities of daily living (ADL) in terms of bathing, dressing, grooming, feeding, toileting and physical ambulation. Total scores for the scale can range from 6 30, with higher scores reflecting greater dependence and more impairment in ADL. Finally, a range of demographic information was also collected (i.e. age, gender, length of stay in the LTC facility etc.). Data analysis Data were analysed using the Statistical Package for the Social Sciences Version 17.0 (SPSS Inc., Chicago, IL, USA). Prior to analysis, basic frequencies were run on the data to screen for missing values and outliers and to establish data entry accuracy. For the QOL-AD, cases (completed questionnaires) were included in analysis if 80% of items (questions) were answered (i.e. 12 out of 15). Using this criterion, one case was removed from analysis as it included six missing items. For the DQOL, 19 cases were excluded from statistical analysis. Specifically, 18 participants did not complete any of the items on the questionnaire and one participant completed just the first 11 items (out of 30). Following this, a missing values analysis was conducted on the 60 completed QOL-AD and 42 completed DQOL questionnaires. This identified three cases requiring case mean substitution on the QOL-AD and two cases on the DQOL subscale feelings of belonging. Mean scores were computed for the QOL-AD and for each of the DQOL s five subscales. Internal consistency was verified through the computation of Cronbach s alpha (a) and basic frequencies were run for participant demographics. Following inspection of completion rates of the two scales, a one-way ANOVA was undertaken to explore differences between participants who did or did not complete the DQOL by age, length of stay, MMSE score and PSMS score. To measure the association between the DQOL (overall and five subscales) and the QOL-AD, a series of Pearson productmoment correlations were computed. For all statistical tests, reported significant differences are at the p-value of 0Æ05. Results Sample characteristics A total of 61 people with dementia were formally enrolled into the study. As shown in Table 1, the majority of these participants were aged between years (75Æ4%), were women (70Æ5%) and widowed (65Æ6%). Most had mild cognitive impairment (62Æ3%), as assessed on the MMSE, and a third had formally been diagnosed with dementia (36Æ1%). As expected with this population, comorbidities were frequently reported, with these chiefly affecting the circulatory (78Æ7%) or musculoskeletal systems (73Æ8%) and, to a lesser extent, the digestive/gastrointestinal system (44Æ3%) or vision/hearing (41Æ0%). Participants most commonly had moderate levels of functioning regarding ADL (44Æ3%), as assessed on the PSMS, although a minority (6Æ6%) were considered to be totally independent. Most were receiving low care (75Æ4%) and had lived in one of the sampled LTC facilities for less than 18 months (68Æ9%). Ability to complete measures Participants were interviewed by RAs on the two self-report measures. Sixty participants completed the QOL-AD, resulting in a 98Æ4% response rate. The remaining participant, although completing the first nine items on the questionnaire, had 40% of responses missing, therefore making it inappropriate to impute missing values and include in the statistics. 4 Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing

5 Original article Table 1 Sample characteristics Characteristic Sub-category n (%) Gender Female 43 (70Æ5) Male 18 (29Æ5) Age (1Æ6) (11Æ5) (24Æ6) (39Æ3) (18Æ0) >96 3 (4Æ9) Marital status Married 17 (27Æ9) Widowed 40 (65Æ6) Single 2 (3Æ3) Divorced 2 (3Æ3) Facility Facility A 24 (39Æ3) Facility B 12 (19Æ7) Facility C 6 (9Æ8) Facility D 19 (31Æ1) Level of care Low care 46 (75Æ4) High care 12 (19Æ7) Special care unit 3 (4Æ9) Length of stay <8 months 24 (39Æ3) 8 18 months 18 (29Æ5) >18 months 19 (31Æ1) Dementia diagnosis No 39 (63Æ9) Yes 22 (36Æ1) Cognitive Early-stage (20 30) 38 (62Æ3) impairment/mmse Mid-stage (10 19) 22 (36Æ1) score Late-stage (0 9) 1 (1Æ6) Comorbidities Circulatory system 48 (78Æ7) Musculoskeletal 45 (73Æ8) Respiratory 4 (6Æ6) Dermatological 12 (19Æ7) Endocrine 21 (34Æ4) Genitourinary 16 (26Æ2) Digestive/gastrointestinal 27 (44Æ3) Vision/hearing 25 (41Æ0) Mental health 20 (32Æ8) Impairment in 6: Greater independence 4 (6Æ6) ADLs/PSMS (24Æ6) Score (44Æ3) (24Æ6) 25 30: Greater dependence 0 (0Æ0) n =61. ADL, activities of daily living; PSMS, Physical Self Maintenance Scale; MMSE, Mini Mental State Exam. Of the 60 participants completing the QOL-AD, missing values analysis showed that just 0Æ6% of data (five items) were missing. Two of these missing items were for question 11 (ability to do things for fun), two were for question 13 (ability to live with others) and one was for question 13 (ability to make choices in one s life). In exploring completion rates for the DQOL, only 42 participants were able to complete the questionnaire, bringing Comparison of the DQOL and QOL-AD the response rate down to 68Æ9%. Of the remaining 19 participants, 18 did not complete any part of the questionnaire and one was able to complete just the first 11 questions (out of 30; 63Æ3% missing). Reasons for not completing the DQOL, as noted by RAs, included participants becoming visibly agitated or upset and/or being unable to provide meaningful or coherent responses, which made it inappropriate to commence or continue the interview. Of the 42 participants completing the DQOL, missing values analysis showed that just 0Æ2% of data (two items) were missing and this was for question 11 (that people liked you), which was an item from the feelings of belonging subscale. In comparing the demographic profile of those participants who did (n = 42), or did not (n = 19) complete the DQOL, Table 2 shows that there was a significant difference according to the extent of cognitive impairment (F 1,59 =30Æ35, p < 0Æ001). Specifically, those unable to complete the DQOL had greater cognitive impairment than those who completed the measure (mean MMSE = 16Æ42 compared with 23Æ12 respectively). Although just outside of statistical significance, it is also worth noting the difference in the levels of functional impairment on ADLs between those who did or did not complete the DQOL (F 1,59 =3Æ22, p =0Æ078). Indeed, those who could not complete the measure had greater functional impairment, as measured on the PSMS, than those who completed the scale (mean PSMS = 16Æ0 compared with 13Æ86 respectively). Neither age nor length of stay in the LTC facility significantly influenced completion rates of the DQOL. Psychometric properties and extent of correlation between the QOL measures In this sample, the internal reliability was good for the QOL- AD scale (0Æ86), but there were varying levels of reliability calculated for the five DQOL subscales. Specifically, internal reliability was highest for absence of negative affect (0Æ79) and sense of aesthetics (0Æ70) and lowest for feelings of belonging (0Æ48) and positive affect (0Æ58). The subscale self-esteem had a moderately acceptable reliability coefficient of 0Æ64. In terms of the correlation between the two QOL measures, Table 3 shows that the QOL-AD was significantly correlated with each of the five DQOL scales, and the overall item. Specifically, the strongest correlation was between the QOL-AD and the DQOL s overall item (r =0Æ519, n = 42, p < 0Æ001) and on the subscale positive affect (r =0Æ504, n = 42, p < 0Æ01). In comparison, the weakest correlations were between the QOL-AD and the DQOL s subscales absence of negative affect (r =0Æ307, n = 42, p < 0Æ05) and aesthetics (r =0Æ317, n = 42, p < 0Æ05). Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing 5

6 W Moyle et al. Dependent variables Completed DQOL (n = 42) Did not complete DQOL (n = 19) ANOVA test statistics (n =61) Mean (SD) Mean (SD) F p Table 2 One-way ANOVAs comparing those who did or did not complete the DQOL by cognitive impairment, functional impairment, age and length of stay in longterm care facility MMSE raw score 23Æ12 (4Æ30) 16Æ42 (4Æ62) 30Æ35 0Æ000** PSMS raw score 13Æ86 (4Æ04) 16Æ00 (4Æ90) 3Æ22 0Æ078 Age (years) 87Æ12 (4Æ56) 85Æ63 (6Æ10) 1Æ12 0Æ293 Length of stay (months) 16Æ60 (23Æ51) 20Æ32 (18Æ27) 0Æ37 0Æ544 **p < 0Æ001. DQOL, Dementia Quality of Life questionnaire; MMSE, Mini Mental State Exam; PSMS, Physical Self Maintenance Scale. Table 3 Pearson s correlation coefficients (r) for the QOL-AD and the DQOL s five subscales DQOL Discussion QOL-AD Overall 0Æ519 0Æ000** Aesthetics 0Æ317 0Æ041* Feelings of belonging 0Æ465 0Æ002** Positive affect 0Æ504 0Æ001** Absence of negative affect 0Æ307 0Æ048* Self-esteem 0Æ403 0Æ008** *p < 0Æ05; **p < 0Æ01; n = 43. QOL-AD, Quality of Life Alzheimer s Disease questionnaire; DQOL, Dementia Quality of Life questionnaire. This study involved a comparative analysis of the DQOL and QOL-AD as instruments for use with older people with dementia in LTC facilities. It was hoped that the findings would be of practical use for those seeking the views of older people with dementia on their QOL, by providing timely insight into how the two, well-known and well-used, scales performed when employed in the same sample of participants in LTC facilities. First, our study found that the QOL-AD had a higher rate of completion than the DQOL when used with the same sample of older people with dementia; a finding broadly consistent with previous literature (Selwood et al. 2005, Sloane et al. 2005). Of those 18 participants unable to complete the DQOL, RAs noted that this was because they became visibly agitated or upset and/or were unable to provide meaningful or coherent responses, thus making it inappropriate to continue the survey. In exploring sample characteristics of those who did, and did not complete the DQOL, our study found that there were significant differences between participants level of cognitive impairment and, to a lesser extent, physical impairment. Specifically, r p those unable to complete the DQOL had greater cognitive impairment and were more physically dependent compared with those who were able to complete the measure. These findings draw support from previous research that has shown, when there is evidence of more advanced cognitive impairment, the DQOL is more difficult for participants to complete (Brooker et al. 2007), in comparison to the QOL- AD, which can be successfully used with persons with more severe impairment (Thorgrimsen et al. 2003, Selwood et al. 2005, Hoe et al. 2006). Although the DQOL was developed for use in people with mild-to-moderate dementia, this study found that the complexity of the instrument and the emotions that arose from the interview questions impacted on participants ability to complete their assessment of QOL. The QOL-AD, however, was developed for use in people with early-to-severe stage dementia, and the strong participant completion rates in this study support the use of this instrument. At a practical level, nursing staff can glean important insight into the dementia-affected person s perceptions of their QOL from the QOL-AD and this could be used to develop activities and interventions to maintain or improve QOL. For instance, if LTC facility residents rated the QOL-AD item ability to make choices in one s life poorly, nursing staff may think it appropriate to offer more opportunities to consult and engage with residents to improve well-being, such as including them in the design/ layout of communal living areas (Knight et al. 2010). Similarly, items such as ability to do things for fun and ability to keep busy may offer up opportunities for nursing staff to investigate what activities each resident prefers and, as recommended (Vernooij-Dassen et al. 2010), develop individualised and tailored interventions around the likes and needs of residents. Although the time taken to complete the measures was not considered to be of importance in this study, the DQOL is considerably longer than the QOL-AD and the RAs reported that the QOL-AD took a shorter time for participants to 6 Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing

7 Original article complete. This may be an important factor for clinicians and researchers to consider when selecting suitable measures. Our study found better internal reliability for the QOL-AD than the DQOL s five subscales, when used with the same sample of residents in LTC facilities. These findings are in line with existing literature, which reports higher reliability values for the QOL-AD than the DQOL, where feelings of belonging is typically the least reliable subscale and absence of negative affect the most reliable subscale (Sloane et al. 2005). Despite such differences in psychometric robustness, however, our findings also show that the two QOL measures significantly and positively correlated with each other, and this was stronger than that reported elsewhere (Sloane et al. 2005). This suggests that the two QOL instruments, whilst incorporating different domains and different scoring methods (i.e. QOL-AD global score, DQOL subscales), were broadly measuring the same construct when used with the same sample of participants. Perhaps, more importantly, however, this finding could be used to support the argument that older people with dementia can reliably report their QOL, as both measures were able to capture these assessments (Lawton 1994, Brod et al. 2000, Kane et al. 2003, Thorgrimsen et al. 2003, Moyle et al. 2007, O Connor et al. 2007, Trigg et al. 2007, Arlt et al. 2008). As such, the use of either measure would enhance QOL research by ensuring that the subjective experience is recognised and that the person with dementia is acknowledged as important informants of their QOL. Limitations There are several factors in this study that would limit the interpretation and the ability to generalise the results. The participants were not randomly selected, resulting in a sample from four LTC facilities owned and operated by one aged care provider. In addition, the sample was relatively small, and only two QOL instruments were compared. To enable a more accurate picture of the reliability of QOL instruments, data would need to be gathered from a larger number of facilities and participants, using several QOL instruments. However, this article is not intended to be a comprehensive appraisal of all QOL instruments but a comparison of how two, well-known and well-used, scales performed in the same population of older people with dementia in LTC facilities. Conclusion Whilst it is keenly recognised that there is no gold standard or superior instrument in assessing QOL (Edelman et al. 2005, Sloane et al. 2005), this study has shown that both the QOL-AD and DQOL are useful instruments for capturing QOL from the perspective of the person with dementia. However, given that the QOL-AD had better rates of completion and internal reliability in this study, the QOL-AD may be the most favourable instrument to employ, particularly with those with more severe cognitive impairment and also, to a lesser extent, functional impairment. Researchers should, however, consider the type of data that they require and for what purpose before making an informed decision on which instrument to employ. It may also be advisable to examine QOL using at least two measurements and to also consider collection of qualitative data as a complementary source of information to ensure the best assessment of QOL is undertaken and the perspective of the person with dementia is truly captured. Relevance to clinical practice Research that seeks to explore QOL of older people with dementia in LTC should strive to include measures that capture the perspective of the person with dementia. This study found that people with dementia could provide reliable and important insight into QOL. In employing disease-specific self-report instruments, this study found both the QOL-AD and DQOL to be good, reliable and appropriate tools for assessing QOL from the perspective of the person with dementia, with the strong correlation between the two suggesting that similar aspects of the construct were being measured. In instances where QOL assessments are sought from participants with more advanced cognitive impairment and, to a lesser extent, functional impairment, it may be most favourable to employ the QOL-AD questionnaire. In addition, the QOL-AD s good completion rate, psychometric robustness and the potential for a shorter completion time also promote the use of this measure further. Acknowledgements Comparison of the DQOL and QOL-AD The authors acknowledge support and contributions by RSL Care management (particularly Deborah Oxlade and Jenni Marshall), facility staff, family and residents and members of the International Advisory Panel. This article reports on an outcome of a larger collaborative research project funded by the Australian Research Council (LP ) under the Linkage Project Scheme for and RSL Care, the industry partner. Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing 7

8 W Moyle et al. Contributions Study design: WM, LV; data collection and analysis: WM, SG, LV, NG, JM and manuscript preparation: WM, NG, JM. Conflict of interest None declared. References American Psychiatric Association (1994) DSM-IV: Diagnostic and Statistical Manual of Mental Disorders. American Psychiatric Association, Washington DC. Arlt S, Hornung J, Eichenlaub M, Jahn H, Bullinger M & Petersen C (2008) The patient with dementia, the caregiver and the doctor: cognition, depression and quality of life from three perspectives. International Journal of Geriatric Psychiatry 23, Banerjee S, Samsi K, Petrie C, Alvir J, Treglia M, Schwam E & del Valle M (2009) What do we know about quality of life in dementia? A review of the emerging evidence on the predictive and explanatory value of disease specific measures of health related quality of life in people with dementia. 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9 Original article Comparison of the DQOL and QOL-AD of life in dementia: selection of the appropriate scale. International Journal of Geriatric Psychiatry 22, Selai C & Trimble MR (1999) Assessing quality of life in dementia. Aging & Mental Health 3, Selwood A, Thorgrimsen L & Orrell M (2005) Quality of life in dementia: a one-year follow-up study. International Journal of Geriatric Psychiatry 20, Sloane P, Zimmerman S, Williams C, Reed P, Gill K & Preisser J (2005) Evaluating the quality of life of long-term care residents with dementia. The Gerontologist 45, Thompson L & Kingston P (2004) Measures to assess the quality of life for people with advanced dementia: issues in measurement and conceptualisation. Quality in Ageing 5, Thorgrimsen L, Selwood A, Spector A, Royan L, de Madariaga Lopez M, Woods R & Orrell M (2003) Whose quality of life is it anyway? The validity and reliability of the Quality of Life-Alzheimer s Disease (QOL-AD) scale. Alzheimer Disease & Associated Disorders 17, Trigg R, Jones RW & Skevington SM (2007) Can people with mild to moderate dementia provide reliable answers about their quality of life? Age and Ageing 36, Vernooij-Dassen M, Vasse E, Zuidema S, Cohen-Mansfield J & Moyle W (2010) Psychosocial interventions for dementia patients in long-term care. International Psychogeriatrics 22, Walker A & Lowenstein A (2009) European perspectives on quality of life in old age. European Journal of Ageing 6, Whitehouse PJ, Patterson MB & Sami SA (2003) Quality of life in dementia: ten years later. Alzheimer Disease & Associated Disorders 17, The Journal of Clinical Nursing (JCN) is an international, peer reviewed journal that aims to promote a high standard of clinically related scholarship which supports the practice and discipline of nursing. For further information and full author guidelines, please visit JCN on the Wiley Online Library website: wileyonlinelibrary.com/journal/jocn Reasons to submit your paper to JCN: High-impact forum: one of the world s most cited nursing journals and with an impact factor of 1Æ194 ranked 16 of 70 within Thomson Reuters Journal Citation Report (Social Science Nursing) in One of the most read nursing journals in the world: over 1 million articles downloaded online per year and accessible in over 7000 libraries worldwide (including over 4000 in developing countries with free or low cost access). Fast and easy online submission: online submission at Early View: rapid online publication (with doi for referencing) for accepted articles in final form, and fully citable. Positive publishing experience: rapid double-blind peer review with constructive feedback. Online Open: the option to make your article freely and openly accessible to non-subscribers upon publication in Wiley Online Library, as well as the option to deposit the article in your preferred archive. Ó 2011 Blackwell Publishing Ltd, Journal of Clinical Nursing 9