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.
Sengupta
Nishan
N
Center for Pharmaceutical Appraisal and Outcomes Research, Abbott Lab, Lake Bluff, Illinois, USA.
Nichol
Michael B
MB
Wu
Joanne
J
Globe
Denise
D
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