European Scleroderma Study Group (ESCSG) Activity Index is correlated to quality of life measures both at admission and overtime

Objectives: EScSG activity index has been validated for construct validity (1). Its discriminant validity awaits to be investigated. In order to address this aspect, we investigated the relationships between the activity index and Health Assessment Questionnaire-Disability Index, and physical and mental component scores (PCS and MCS) of Short Form-36 (SF36). Methods: 149 SSc patients consecutively admitted to a tertiary center were investigated for EScSG activity index, HAQ-DI and PCS and MCS of SF36 at enrolment and after 1 year. The change () for each measure was calculated. Results: EScSG activity index was found to be correlated to HAQ-DI, PCS and MCS both at admission (Rho0.41, p0.0001; Rho0.41, p0.0001; Rho 0.29, p0.0004, respectively) and after 1 year (Rho 0.33, p 0.0001; Rho 0.35, p0.0001; Rho0.21, p0.0094 respectively). Moreover, the change between the value of the activity index at 1 year and that at admission ( activity index) was significantly correlated to HAQ-DI, PCS, MCS (Rho0.16, p0.04; Rho 0.24, p0.003; Rho- 0.48, p0.0036, respectively). Conclusion: HAQ-DI and SF36 (PCS and MCS) are considered to be validated outcome measures in SSc. Our results support the construct and the discriminant validity of EScSG activity index. References: 1 –Valentini G. et al. European Scleroderma Study Group to define disease