Interpreting parental proxy reports of (health-related) quality of life for children with unilateral cochlear implants

Objective: To examine what factors are associated with EuroQol EQ-5D scores in children after unilateral cochlear implantation and to explore parental conceptualisations of health-related quality of life (HRQL) and quality of life (QoL). Methods: Face to face interviews were conducted with the parents of 222 implanted children, in an attempt to elicit information on their child's HRQL and QoL. Post-implant, the child's HRQL was measured using the EQ-5D, completed by parental proxy. Regression analysis was undertaken in order to estimate the association between the child EQ-5D score and child characteristics, child performance, and parental characteristics, in order to assess the construct validity of the EQ-5D. HRQL was also measured using the EuroQol visual analogue scale (VAS), where the endpoints were the best and worst imaginable health state, and a VAS was also used to measure QoL (endpoints: best/worst imaginable QoL). Parents were asked to estimate scores on both these VAS measures both post-implantation and (retrospectively) pre-implantation. Throughout the HRQL and QoL elicitation process, subjects' comments, and observations were noted. Results: Children who had an additional disability (p < 0.001), were male (p < 0.05) or had a lower level of auditory perception (p < 0.001) were estimated to have lower EQ-5D scores, as were children whose parents who left school before age 18 years (p < 0.05). According to the EuroQol VAS the mean difference between pre- and post-implantation score was 0.14, compared to 0.35 for the QoL VAS, demonstrating that parents tended not to see HRQL and QoL as equivalent. As 67% of parents deemed there to be no difference between the pre- and post-implant EuroQol VAS scores we also infer that the majority of parents rejected the notion of deafness being a HRQL issue. Conclusion: The evidence relating to the construct validity of the EQ-5D is variable-though it was able to discriminate between children with certain levels of auditory performance, it could not discriminate between children who differed in other ways. By limiting outcome from cochlear implantation to HRQL, as opposed to QoL, the benefits of cochlear implants are likely to be underestimated. (C) 2006 Elsevier Ireland Ltd. All rights reserved.