title: Internal consistency and construct validity of the Quality of Life in Alzheimer's Disease (QoL-AD) proxy – a secondary data analysis
abstract: Background: The maintenance and promotion of Quality of Life (QoL) of people with dementia is a major outcome in intervention studies and health care. The Quality of Life Alzheimer's Disease (QoL-AD) is an internationally recommended QoL measurement also available in German language. Until now, only a few results on the psychometric properties of the German QoL-AD were available. Objective: Evaluation of internal consistency and construct validity of the QoL-AD proxy. Method: A principal component analysis (secondary data analysis) of the 13 QoL-AD items was carried out based on the total sample of 234 people with dementia from nine nursing homes in Germany. Subsequently, the internal consistency of the identified factors was examined using Cronbach's alpha. Results: Two factors physical and mental health and social network were determined. Both factors explain 53 % of the total variance. The stability of both factors was validated in two sensitivity analyses. The internal consistency is good for both factors with a Cronbach's alpha of 0.88 (physical and mental health) and 0.75 (social network). Conclusion: The QoL-AD proxy allows the assessment of two relevant health-related QoL domains of people with dementia. However, in future studies especially the inter-rater reliability of the QoL-AD proxy has to be examined.
authors.affiliation: 1 Katholische Hochschule Nordrhein-Westfalen (KatHO NRW), Abteilung Köln.
authors.forename: Jonas
authors.initials: J
authors.lastname: Hylla
authors.affiliation: 2 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Witten.|3 Department für Pflegewissenschaft, Fakultät für Gesundheit, Universität Witten/Herdecke (UW/H), Witten.
authors.forename: Christian G G
authors.initials: CG
authors.lastname: Schwab
authors.affiliation: 1 Katholische Hochschule Nordrhein-Westfalen (KatHO NRW), Abteilung Köln.|4 Deutsches Institut für angewandte Pflegeforschung (dip), Köln.
authors.forename: Michael
authors.initials: M
authors.lastname: Isfort
authors.affiliation: 2 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Witten.|3 Department für Pflegewissenschaft, Fakultät für Gesundheit, Universität Witten/Herdecke (UW/H), Witten.
authors.forename: Margareta
authors.initials: M
authors.lastname: Halek
authors.affiliation: 2 Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Witten.|3 Department für Pflegewissenschaft, Fakultät für Gesundheit, Universität Witten/Herdecke (UW/H), Witten.
authors.forename: Martin N
authors.initials: MN
authors.lastname: Dichter
mesh_terms: D000203:Activities of Daily Living / Q000145:classification / Q000523:psychology; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000451:nursing* / Q000523:psychology*; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D009730:Nursing Assessment / Q000706:statistics & numerical data*; D019727:Proxy; D011594:Psychometrics / Q000706:statistics & numerical data*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012648:Self Care / Q000145:classification / Q000523:psychology; D011795:Surveys and Questionnaires
keywords: Demenz; Konstruktvalidität; construct validity; dementia; factorial validity; faktorielle Validität; gesundheitsbezogene Lebensqualität; health related quality of life; internal consistency; interne Konsistenz; nursing home; stationäre Altenpflegeeinrichtung