Construct validity of SF-6D health state utility values in an employed population

BACKGROUND: Health utility values permit cost utility analysis in workplace health promotion; however, utility measures of working populations have not been validated.

AIM: To investigate construct validity of SF-6D health utility in a public service workforce.

METHODS: SF-12v2 Health Survey was administered to 3,408 randomly selected public service employees in Australia in 2010. SF-12 scores were converted to SF-6D health utility values. Associations and correlates of SF-6D with health, socio-demographic and work characteristics [comorbidities, body mass index (BMI), Kessler-10 psychological distress (K10), education, salary, effort-reward imbalance (ERI), absenteeism] were explored. Ceiling effects were analysed. Nationally representative employee SF-6D values from the Household, Income and Labour Dynamics in Australia (HILDA) survey (n = 11,234) were compared. All analyses were stratified by sex.

RESULTS: Mean (SE) age was 45.7 (0.35) males; 44.5 (0.22) females. Females represented 72 % of the sample. Mean (SE) health utility 0.792 (0.004); 0.771 (0.003) was higher in males. SF-6D demonstrated both a significant inverse association (p < 0.01) and negative correlations (female; male) with K10 (r = -0.63; r = -0.66), comorbidity count (r = -0.40; r = -0.33), ERI (r = -0.37; r = -0.34) and absenteeism (p < 0.005, r = -0.25; r = -0.21). Mean (SE) SF-6D in HILDA was 0.792 (0.002); 0.775 (0.003) males; females. Correlates and associations in all samples were similar. The general employed demonstrated a significant inverse association with age and positive association with salary. SF-6D was independent of BMI.

CONCLUSIONS: Psychological distress, comorbidity, effort-reward imbalance and absenteeism are negatively associated with employee health. SF-6D is a valid measure of perceived health states in working populations.