Mapping the SF-12 to the EuroQol EQ-5D Index in a national US sample.
BACKGROUND
Preference scores for the Medical Outcomes Study (MOS) SF-12 would enable its use in cost-effectiveness analyses. Previous mapping studies of MOS instruments top reference-based instruments have not examined performance in national samples.


METHODS
15,000 adults in the 2000 Medical Expenditure Panel Survey annual survey including the SF-12 and EQ-5D Index.


METHODS
Regression of the EQ-5D Index scores onto the physical and mental component summary scores of the SF-12, testing 2nd-4th degree polynomial and spline models, including and excluding sociodemographics.


RESULTS
A 2nd degree polynomial model explained 63% of the variance in EQ-5D scores, with robust internal and external validation. More complex mod-els explained minimally additional variance. Compared with EQ-5D valuations, prediction models overestimated the lowest health states (6% of the population).


CONCLUSIONS
The mapped SF-12 yields usable preference-scaled scores, with some caution for the lowest health states.
Franks
Peter
P
Department of Family and Community Medicine, Center for Health Services Research in Primary Care, University of California, Davis, Sacramento 95817, USA. pfranks@ucdavis.edu
Lubetkin
Erica I
EI
Gold
Marthe R
MR
Tancredi
Daniel J
DJ
Jia
Haomiao
H
D000328:Adult; D000368:Aged; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D008297:Male; D008875:Middle Aged; D011788:Quality of Life; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology