Health-Related Quality of Life in Systemic Sclerosis: Feasibility and Construct Validity of Eq-5d

Systemic Sclerosis (SSc) is a chronic disabling disease associated with reduced health-related quality of life (HRQoL). Nonetheless, HRQoL in patients with SSc is often left behind in clinical practice. Our aim was to evaluate the feasibility and construct validity of EQ-5D, a simple and quick self-assessment tool, and to compare its performance with health assessment questionnaire (HAQ) and short form-36 (SF-36) in patients with SSc. For this purpose, we investigated 119 consecutive SSc patients (94% females, median age 63, interquartile range 53-70) referring to three different Rheumatologic Centers. Materials and methods: Acceptability was evaluated based on comments or complaints from the patients and feasibility based on the number of missing data. Correlations were calculated by means of Spearman’s correlation coefficient. Results: EQ-5D was well accepted from patients. The percentage of missing data in at least one EQ-5D domain was 2.5%. Spearman’s correlation coefficients between comparable dimensions of EQ-5D vs. HAQ and vs. SF-36 were > 0.30. Correlation coefficients between less comparable dimensions of EQ-5D vs SF-36 were low. As expected, EQ-5D anxiety/depression domain correlated with none of the HAQ domains. EQ-5D VAS concordance with SF-36 GH and HAQ total score was good (0.59 and 0.57 respectively). Furthermore, we calculated Italian values of EQ-5D index in SSc. Median value and interquartile range (IQR) for EQ-5D index was 0.81 (IQR 0.75-0.86). EQ-5D index demonstrated a correlation coefficient >0.40 with all SF-36 domains and with all HAQ domains, HAQ total and HAQ VAS. Conclusions: Our data demonstrate good acceptability, feasibility, convergent and divergent validity of EQ-5D in patients with SSc. We suggest the use of EQ-5D in SSc patients as a HRQoL measure in clinical practice and in randomized clinical trials and/or in pharmacoeconomic evaluations.