Scalability and internal consistency of the German version of the dementia-specific quality of life instrument QUALIDEM in nursing homes – a secondary data analysis

Abstract

BackgroundQuality of life (Qol) is a widely selected outcome in intervention studies. The QUALIDEM is a dementia-specific Qol-instrument from The Netherlands. The aim of this study is to evaluate the scalability and internal consistency of the German version of the QUALIDEM.MethodsThis secondary data analysis is based on a total sample of 634 residents with dementia from 43 nursing homes. The QUALIDEM consists of nine subscales that were applied to a subsample of 378 people with mild to severe dementia and six consecutive subscales that were applied to a subsample of 256 people with very severe dementia. Scalability, internal consistency and distribution scores were calculated for each predefined subscale using the Mokken scale analysis.ResultsIn people with mild to severe dementia, seven subscales, care relationship, positive affect, negative affect, restless tense behavior, positive self-image, social relations and feeling at home, were scalable (0.31 ≤ H ≤ 0.65) and internally consistent (Rho ≥ 0.62). The subscales social isolation (H = 0.28) and having something to do (H = 0.18) were not scalable and exhibited insufficient reliability scores (Rho ≤ 0.53). For people with very severe dementia, five subscales, care relationship, positive affect, restless tense behavior, negative affect and social relations, were scalable (0.33 ≤ H ≤ 0.65), but only the first three of these subscales showed acceptable internal consistency (Rho 0.59 – 0.86). The subscale social isolation was not scalable (H = 0.20) and exhibited poor internal consistency (Rho = 0.42).ConclusionsThe results show an acceptable scalability and internal consistency for seven QUALIDEM subscales for people with mild to severe dementia and three subscales for people with very severe dementia. The subscales having something to do (mild to severe dementia), negative affect (very severe dementia), social relations (very severe dementia) and social isolation (both versions) produced unsatisfactory results and require revision.

Quality of life of patients with dementia in acute hospitals in Germany: a non-randomised, case–control study comparing a regular ward with a special care ward with dementia care concept

“…Although studies show reliable results of the QUALIDEM in nursing homes even for a short observation period of about 1 week,63 there are no studies that evaluate the reliability and validity for use in hospitals. We have done checks of internal consistencies, which showed that most subdomains of the QUALIDEM perform well with our data and are comparable with results from other validation studies 64. This indicates that the use of the QUALIDEM is feasible for hospital research.…”

Quality of life in people with dementia living in nursing homes: validation of an eight-item version of the QUALIDEM for intensive longitudinal assessment

“…Next to the subscales, we created a composite sum score across all 37 items, which has been used extensively in the literature as well [25][26][27][28][29][30]. Thus, in our analyses, we look into both the comprehensive sum score (Table 2) as well as subscale results ( 'positive affect', 'negative affect', 'restlessness', and 'social relationships' of the full 37-item version of QUALIDEM (i.e., subscale B, subscale C, subscale D, and subscale F) [8,31]. As part of a workshop, the study team was selecting the items based on the following considerations: Two items from four subscales of the German QUALIDEM version were used for the short version.…”

“…Focusing on the psychosocial domains of QoL in PwD, the QoL assessment tool QUALI-DEM showed the best acceptability interviewing PwD and their proxies. It was considered as acceptable in the long and short forms profiling PwD with mild-to-very severe stages of dementia living in nursing homes [4,[7][8][9].…”

Assessing the quality of life and well-being of older adults with physical and cognitive impairments in a German-speaking setting: A systematic review of validity and utility of assessments / Die Erfassung von Lebensqualität und Wohlbefinden älterer Menschen mit psychischen und kognitiven Einschränkungen: ein systematisches Literaturreview zur Validität und Praktikabilität deutschsprachiger Assessments

“…Seine Praktikabilität wird als gut beurteilt (Bouman et al, 2011;Dichter, Bartholomeyczik, Nordheim, Achterberg & Halek, 2011;Gräske et al, 2014). Die Studien stützen die Validität des QUALIDEM, im Bereich Beziehung zu anderen Variablen besteht jedoch noch wenig Evidenz (Arons et al, 2018;Bouman et al, 2011;Dichter et al, 2011Dichter et al, , 2013Dichter et al, , 2014Dichter, Wolschon, Meyer & Kopke, 2016;Ettema, Dröes, de Lange, Mellenbergh & Ribbe, 2007b, 2007aGräske et al, 2014).…”