To assess health values in subjects with systemic sclerosis (SSc) and determine variability explained by demographics, clinical factors, health status, and disease severity.Methods
We interviewed 107 individuals with SSc who attended national and local Scleroderma Foundation meetings in 2005. Health status was measured using the Short Form 36 (SF-36) Physical Component Summary (PCS; range 0–100) and Mental Component Summary (MCS; range 0–100), the Center for Epidemiologic Studies Depression Scale (CES-D; range 0–60), and the Health Assessment Questionnaire (HAQ) disability index (DI; range 0–3). Disease severity was assessed using a visual analog scale (VAS; range 0–150). Health value measures included the 0–100 health rating scale (RS), standard gamble (SG; range 0.0–1.0), and time trade-off (TTO; range 0.0–1.0). We performed univariate analyses to compare scores between participants with limited cutaneous SSc (lcSSc) and diffuse cutaneous SSc (dcSSc), and multivariable analyses for 3 outcome measures: RS, SG, and TTO, controlling for demographics, type of SSc, health status, and disease severity.Results
Of the 107 participants, 48 had dcSSc and 59 had lcSSc. Ninety-seven were women and 83 were white. The median scores for the PCS, MCS, and HAQ DI were 36.9, 45.5, and 0.9, respectively. Fifty-five subjects had significant depressive symptoms (CES-D score ≥16). The median RS, SG, and TTO scores were 62, 0.83 (indicating a willingness to accept up to a 17% risk of immediate death in exchange for perfect health), and 0.88 (indicating a willingness to give up a median of 12% of life expectancy in exchange for perfect health), respectively. Subjects with dcSSc had lower RS scores but higher SG scores (corresponding to a willingness to accept only a smaller risk of death) than subjects with lcSSc. TTO scores were similar in the 2 groups. Health values were variably related to factors such as demographics, VAS score, disease classification, and SF-36 PCS and MCS scores (R2 = 0.22, 0.23, and 0.66 for the SG, TTO, and RS models, respectively).Conclusion
Individuals with dcSSc have lower health ratings but higher SG health values than individuals with lcSSc. These findings have implications for decision analysis and cost-effectiveness analysis.