Mapping the SF-12 to the HUI3 and VAS in a managed care population.
BACKGROUND
Transforming generic health-related quality of life (HRQOL) instruments to a summary utility index is useful for deriving quality-adjusted life years (QALY) in any cost/QALY analysis.


OBJECTIVE
The purpose of this study was to investigate the role of the SF-12 in predicting utility scores derived from Health Utility Index (HUI3) and Visual Analog Scale (VAS).


METHODS
Data were obtained from a survey of 6923 managed care patients in the United States, aged 18 to 93 years, selected by strata of medication usage (at least 1 medication in target year, 5 or more medications, target medications, and both). The SF-12 was used to assess self-reported HRQOL. Utility was measured by the HUI3 and a VAS. The SF-12 items were used to predict HUI3 and VAS scores using ordinary least square regressions, with sociodemographic covariates. A second model entered each SF-12 item as categorized responses. A third model used the Physical Composite and Mental Composite scores to predict HUI3 and VAS scores.


RESULTS
The SF-12 items and sociodemographic covariates accounted for 35% to 55% of the variations in HUI3 and VAS scores, respectively. Age and most SF-12 items were significantly (P < 0.0001) associated with both utility scores in all 3 models.


CONCLUSIONS
This research provides support that an algorithm can be derived from the SF-12 to estimate utility scores based on the HUI3 and VAS for studies in populations where utility has not or cannot be measured directly.
Center for Pharmaceutical Appraisal and Outcomes Research, Abbott Lab, Lake Bluff, Illinois, USA.
Nishan
N
Sengupta
Michael B
MB
Nichol
Joanne
J
Wu
Denise
D
Globe
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D005260:Female; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008329:Managed Care Programs / Q000592:standards* / Q000706:statistics & numerical data; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011788:Quality of Life; D019057:Quality-Adjusted Life Years; D012044:Regression Analysis; D018434:Sickness Impact Profile; D012959:Socioeconomic Factors; D011795:Surveys and Questionnaires / Q000592:standards*; D014481:United States