Health-related quality of life in survivors of tumours of the central nervous system in childhood—a preference-based approach to measurement in a cross-sectional study¹

Abstract

There is an evident need to measure the comprehensive burden of morbidity experienced by survivors of brain tumours in childhood. To this end, a questionnaire based on the Health Utilities Index mark 2 (HUI2) and mark 3 (HUI3) systems was completed independently for a cohort of such children by their parents, by a nurse, by physicians and by a selected group of the children themselves. Each of the HUI2 and HUI3 systems consists of a multi-attribute health status classification scheme linked to a preference function which provides utility scores for levels within single attributes (domains of health) and for global health states. All eligible families (n=44) participated. Even cognitively impaired children of at least 9.5 years of age could complete the questionnaire. The greatest burden of morbidity, occurring in two-thirds of children, was in the attribute of cognition. Surprisingly, almost one-third of children experienced pain. Global health status was lowest in children who underwent radiotherapy before the age of 5 years and the corresponding utility scores were related inversely to the volume irradiated. Children with demonstrable disease had lower scores than those in whom disease was not evident. There was a high level of agreement (intraclass correlation coefficients >0.5) on formal assessment of inter-rater reliability for global health-related quality of life utility scores. The usefulness of measures of health status and health-related quality of life, in children surviving brain tumours, has been demonstrated by this study.

Introduction

Brain tumours are the commonest group of solid tumours in children in industrialised societies, and the incidence of these neoplasms is rising[1]. Furthermore, within some parts of the developing world, in which most children reside, there appears to be a serious problem of under-diagnosis[2]. As the prospects for long-term survival from neoplasms of the central nervous system continue to increase[1], at least for children in industrialised countries, there is growing recognition of the need to address the sequelae of these diseases and of their treatment[1]. The neuropsychological consequences of ‘successful’ therapy for brain tumours of childhood have been well summarised[3], but the comprehensive burden of morbidity that these survivors bear has been less well examined[4].

We have developed and applied instruments, based on Health Utilities Index systems (HUI)[5], for the measurement of morbidity burden. The HUI can capture multiple sequelae and describe varying levels of severity. A pilot study of a small case series of children surviving brain tumours has been reported[4]. The primary purpose of the present study was to investigate the comprehensive (global) health status of a larger group of such children, using a nurse as the primary assessor, and to use a preference-based approach to measurement in order to quantify their health-related quality of life (HRQL). Patrick and Erikson[6]defined HRQL as ‘the value assigned to the duration of life as modified by the impairments, functional states, precautions and social opportunities that are influenced by disease, injury, treatment or policy’. Secondary objectives were an assessment of the proportion of children surviving brain tumours who could complete, by self-report, a questionnaire on their health status; and an assessment of inter-rater agreement (reliability) in health status measurements.

This paper is paired with that of Glaser and colleagues[7]as these are complementary contributions and the repetition of descriptions about several components (such as the HUI classification systems) is thereby avoided. Furthermore, although there are some differences in the survey methods, the populations being sampled are very similar.