Validity of the EQ-5D as a generic health outcome instrument in a heroin-dependent population

Abstract

Objective To evaluate the validity of the EuroQol (EQ-5D) in a population of chronic, treatment-resistant heroin-dependent patients. Methods The EQ-5D is studied relative to the Maudsley Addiction Profile (MAP), the Symptom Checklist (SCL-90) and the European Addiction Severity Index (EuropASI) which were used to assess the participant's physical functioning, mental health and social integration, respectively. Data were gathered from 430 patients participating in the Dutch heroin trials with an intended 12-month treatment period. The EQ-5D was used as a separate health outcome measure. Statistical analyses were conducted using Spearman's and Pearson's correlations. Results The EQ-5D dimensions mobility, self-care and usual activities generally showed low correlations with relevant parameters of the MAP-HSS, SCL-90 and EuropASI ( r = 0.132–0.369). The EQ-5D dimension pain/discomfort showed low to moderate hypothesized correlations with all disease-specific measures ( r = 0.153–0.496). The EQ-5D dimension anxiety/depression showed moderate to high correlations with the SCL-90 (including the sum score) and some of the EuropASI parameters ( r = 0.133–0.615). The EQ-5D utility scores were moderately correlated with the MAP-HSS ( r = −0.468) and the SCL-90 ( r = −0.491) total score and with response to treatment at month 12. Conclusion The majority of hypothesized associations between the EQ-5D and the disease or domain-specific measures could be confirmed. The validity of the EQ-5D-based utility score appears to be suitable in the evaluation of chronic, heroin-dependent populations.