A psychometric evaluation of a Swedish version of the Quality of Life in Late-Stage Dementia (QUALID) scale

Background: The aim of the present study was to evaluate the validity, reliability and responsiveness of a Swedish translation of the Quality of Life in Late-Stage Dementia (QUALID) Scale. Method: A total of 169 elderly residents at 19 dementia special care units in eight long-term care facilities in the Gothenburg city region participated in the study. Assessments were made by 107 proxy informants. Results: Results showed satisfactory levels of internal consistency reliability (Cronbach's alpha coefficients 0.74), acceptable inter-rater reliability between informants (0.69), and high test-retest reliability (0.86). As hypothesized, QUALID scores were also associated with those from other quality-of-life (QoL) indices (criterion validity), as well as with use of psychoactive drugs, and with tests of cognitive impairment (clinical validity). The responsiveness of the questionnaire was also acceptable. Conclusions: As important clinical decisions may derive from perceived QoL effects, it is vital that the QoL data be reliable, valid and sensitive to change. Our evaluations of the psychometric properties of the Swedish QUALID indicate that it satisfactorily meets the need for an instrument to assess QoL in late-stage dementia in Sweden, in a wide range of settings and applications.