Interne Konsistenz und Konstruktvalidität des demenzspezifischen Lebensqualitätsinstruments QUALIDEM - Eine Sekundärdatenanalyse einer Querschnittserhebung.

UNLABELLED

Internal consistency and construct validity of the Quality of Life measurement in dementia QUALIDEM - a secondary data analysis of cross-sectional data Background: Maintaining and improving the Quality of Life (QoL) of people with dementia is the principal aim of nursing and medical care. The QUALIDEM is a theory-based, dementia-specific QoL instrument in the German language. Until now, however, there are hardly any findings on the construct validity.

OBJECTIVE

Evaluation of the item difficulty, internal consistency, discriminant and convergent validity of the German QUALIDEM.

METHOD

The evaluation of the construct validity is based on a Multi-Trait-One-Method approach, using a sample of 167 people with mild to severe dementia and 71 people with very severe dementia.

RESULTS

The correlation between the QUALIDEM subscales and the comparative constructs agitation, depression, anxiety, aberrant motoric behavior, apathy, pain and QoL, measured with the Alzheimer's Disease Related Quality of Life instrument, was confirmed in the expected direction in 82 % of the predefined hypotheses. The correlation coefficients range between 0.04 and -0.60 (discriminant validity) and -0.21 and 0.71 (convergent validity). For the majority of QUALIDEM subscales a good internal consistency could be demonstrated.

CONCLUSION

The results indicate first indications for the construct validity of the QUALIDEM subscales and for the further development of the instrument. In future studies, the validity of the German QUALIDEM should be further investigated.