The EQ-5D is a standardized, nondisease-specific instrument for evaluating patients' preference-based valuations of health-related quality of life (HRQoL). This study's purpose was to determine the psychometric properties of EQ-5D in patients with irritable bowel syndrome (IBS).
Data from four European IBS studies were assessed: UK (n = 161 and n = 297), Spain (n = 503), and Germany (n = 100). The EQ-5D is a five-item health state descriptive system used to develop health states (EQ-5D ) and a visual analog scale (VAS) (0–100 from worst to best imaginable health state, EQ-5D ). Measures used with the EQ-5D included the SF-36, Irritable Bowel Syndrome—Quality of Life (IBS-QOL), and both subjective and clinical global assessments of IBS. Convergent validity was assessed using SF-36 and IBS-QOL data, discriminant validity using global ratings of IBS severity, and responsiveness by subjective and physician assessment of condition.
Moderate-to-high associations (r ≥ 0.33) were seen between the EQ-5D and the SF-36 and IBS-QOL subscales. Mean response scores to EQ-5D dimensions and the EQ-5D score were significantly better for control patients than for patients with IBS (all P 0.001). The EQ-5D and the EQ-5D were responsive in patients using both a self-perceived (Subject's Global Assessment) and physician-rated (Clinic Global Assessment) improvement.
The EQ-5D performs well in comparison to general and disease-specific outcomes. It is a valid and responsive measure that can be used to generate preference-based valuations of HRQoL in patients with IBS and useful for comparisons in clinical and cost-effectiveness studies.