The impact of differences in EQ-5D and SF-6D utility scores on the acceptability of cost-utility ratios: results across five trial-based cost-utility studies.
OBJECTIVE
This article investigates whether differences in utility scores based on the EQ-5D and the SF-6D have impact on the incremental cost-utility ratios in five distinct patient groups.


METHODS
We used five empirical data sets of trial-based cost-utility studies that included patients with different disease conditions and severity (musculoskeletal disease, cardiovascular pulmonary disease, and psychological disorders) to calculate differences in quality-adjusted life-years (QALYs) based on EQ-5D and SF-6D utility scores. We compared incremental QALYs, incremental cost-utility ratios, and the probability that the incremental cost-utility ratio was acceptable within and across the data sets.


RESULTS
We observed small differences in incremental QALYs, but large differences in the incremental cost-utility ratios and in the probability that these ratios were acceptable at a given threshold, in the majority of the presented cost-utility analyses. More specifically, in the patient groups with relatively mild health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the EQ-5D to estimate utility. While in the patient groups with worse health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the SF-6D to estimate utility.


CONCLUSIONS
Much of the appeal in using QALYs as measure of effectiveness in economic evaluations is in the comparability across conditions and interventions. The incomparability of the results of cost-utility analyses using different instruments to estimate a single index value for health severely undermines this aspect and reduces the credibility of the use of incremental cost-utility ratios for decision-making.
Joore
Manuela
M
Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Centre, Maastricht, The Netherlands. m.joore@mumc.nl
Brunenberg
Danielle
D
Nelemans
Patricia
P
Wouters
Emiel
E
Kuijpers
Petra
P
Honig
Adriaan
A
Willems
Danielle
D
de Leeuw
Peter
P
Severens
Johan
J
Boonen
Annelies
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000191:economics / Q000523:psychology; D003362:Cost-Benefit Analysis / Q000379:methods* / Q000592:standards; D005260:Female; D006801:Humans; D006973:Hypertension / Q000191:economics / Q000523:psychology; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000191:economics / Q000523:psychology; D010043:Outcome and Process Assessment, Health Care; D016584:Panic Disorder / Q000191:economics / Q000523:psychology; D019057:Quality-Adjusted Life Years; D016032:Randomized Controlled Trials as Topic; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D013167:Spondylitis, Ankylosing / Q000191:economics / Q000523:psychology; D055815:Young Adult