Which health-related quality of life score? A comparison of alternative utility measures in patients with Type 2 diabetes in the ADVANCE trial.
BACKGROUND
Diabetes has a high burden of illness both in life years lost and in disability through related co-morbidities. Accurate assessment of the non-mortality burden requires appropriate health-related quality of life and summary utility measures of which there are several contenders. The study aimed to measure the impact of diabetes on various health-related quality of life domains, and compare several summary utility measures.


METHODS
In the ADVANCE (Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation) study, 978 Australian patients with Type 2 diabetes completed two health-related quality of life questionnaires at baseline: the EQ-5D and the SF-36v2, from which nine summary utility measures were calculated, and compared. The algorithms were grouped into four classes: (i) based on the EQ-5D; (ii) using fewer items than those in the SF-12 (iii) using the items in the SF-12; and (iv) using all items of the SF-36.


RESULTS
Overall health-related quality of life of the subjects was good (mean utility ranged from 0.68 (+/-0.08) to 0.85(+/-0.14) over the nine utility measures) and comparable to patients without diabetes. Summary indices were well correlated with each other (r = 0.76 to 0.99), and showed lower health-related quality of life in patients with major diabetes-related events such as stroke or myocardial infarction. Despite the smaller number of items used in the scoring of the EQ-5D, it generally performed at least as well as SF-36 based methods. However, all utility measures had some limitation such as limited range or ceiling effects.


CONCLUSIONS
The summary utility measures showed good agreement, and showed good discrimination between major and minor health state changes. However, EQ-5D based measures performed as well and are generally simpler to use.
Glasziou
Paul
P
Centre for Evidence-Based Practice, Institute of Health Sciences, Oxford University, Oxford, UK. paul.glasziou@dphpc.ox.ac.uk
Alexander
Jan
J
Beller
Elaine
E
Clarke
Philip
P
D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001315:Australia / Q000453:epidemiology; D015331:Cohort Studies; D015897:Comorbidity; D017281:Cost of Illness; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D003925:Diabetic Angiopathies / Q000453:epidemiology; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D015203:Reproducibility of Results