This study aimed to validate the Short-Form 12-Item Survey-version 2 (SF-12v2) in an older (≥65 years old) US population as well as estimate disutilities associated with relevant conditions, using data from the Medical Expenditure Panel Survey longitudinal panel (2014-2015). The physical component summary (PCS) and mental component summary (MCS) scores were examined for reliability (internal consistency, test-retest), construct validity (convergent and discriminant, structural), and criterion validity (concurrent and predictive). The study sample consisted of 1040 older adults with a mean age of 74.09 years (standard deviation: 6.19) PCS and MCS demonstrated high internal consistency (Cronbach's alpha-PCS: 0.87, MCS: 0.86) and good and moderate test-retest validity, respectively (intraclass correlation coefficient: PCS:0.79, MCS:0.59)). The questionnaire demonstrated sufficient convergent and discriminant ability. Confirmatory factor analysis showed adequate fit with the theoretical model and structural validity (goodness of fit = 0.9588). Concurrent criterion validity and predictive criterion validity were demonstrated. Activity limitations, functional limitations, arthritis, coronary heart disease, diabetes, myocardial infarction, stroke, angina, and high blood pressure were associated with disutilities of 0.18, 0.15, 0.06, 0.07, 0.07, 0.06, 0.09, 0.06, and 0.08, respectively, and demonstrated the responsiveness of the instrument to these conditions. The SF-12v2 is a valid and reliable instrument in an older US population.
Keywords: Medial Expenditure Panel Survey; SF−12v2; disutility; health-related quality of life; older adults; psychometric properties; quality of life; reliability; utility; validity.