Validation of an individualised quality of life measure in older day hospital patients.
BACKGROUND
To test the ease of use, reliability, responsiveness and construct validity of the Patient Generated Index, an individualised quality of life score, in older people attending a Medicine for Older People Day Hospital.


METHODS
Prospective longitudinal study in patients attending a specialist Medicine for Older People Day Hospital in Scotland. The Patient Generated Index was administered at baseline, one week later, and at the end of Day Hospital attendance. Functional Limitations Profile, Hospital Anxiety and Depression Score, Barthel index and global subjective impressions of change were also collected and compared with baseline scores and change in Patient Generated Index scores. Reliability was assessed using intraclass correlation coefficients in subjects reporting no change in global quality of life; responsiveness was assessed using effect size and Guyatt coefficients in subjects reporting change in global quality of life. External validity was assessed via correlation with measures of physical function, comorbid disease and psychological state.


RESULTS
75 patients were enrolled, mean age 81 years. Mean completion time was 5.0 minutes at baseline. Reliability was moderate (intraclass correlation coefficient 0.72) but there were weak and inconsistent responses to change (effect sizes 0.02 to 0.15; Guyatt responsiveness coefficient 0.29). Patient Generated Index scores correlated with Functional Limitation Profile scores (r = 0.51, p < 0.001), baseline anxiety score (r = -0.25, P = 0.039) and baseline depression score (r = -0.37, P = 0.002) but displayed only weak, non-significant correlation with number of comorbid diseases (r = -0.22, P = 0.07), number of medications (r = -0.21, P = 0.08) and Barthel score (r = 0.09, p = 0.45).


CONCLUSIONS
The Patient Generated Index appears moderately reliable and easy to complete, but is poorly responsive to change, limiting its usefulness in clinical practice or research.
Witham
Miles D
MD
Section of Ageing and Health, University of Dundee, Ninewells Hospital, Dundee DD1 9SY, UK. m.witham@dundee.ac.uk
Fulton
Roberta L
RL
Wilson
Lucy
L
Leslie
Carolyn A
CA
McMurdo
Marion E T
ME
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D003631:Day Care, Medical; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D006299:Health Services for the Aged; D006305:Health Status Indicators; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D011788:Quality of Life; D015203:Reproducibility of Results; D012606:Scotland; D011795:Surveys and Questionnaires