Estimating the value of a generic quality-of-life measure

In this paper, data from a clinical trial of a new antiviral agent for treating patients with zoster are used to answer the following question: Does the Nottingham Health Profile (NHP) add to the information obtained from the clinical measures? Three ways in which the NHP could add information are measured. First, Cox's regression analysis is used to determine whether health-related quality-of-life scores obtained at diagnosis give information about disease prognosis. Second, changes in mean NHP scores in different dimensions are computed after pain resolution to determine whether NHP scores provide more sensitive indicators of disease resolution. Third, linear regression is used to determine whether the impacts of disease on quality of life are measured adequately by the clinical parameters. These analyses show that use of the physical mobility and energy dimensions of the NHP increases understanding of disease prognosis; demonstrates the continuing impact of zoster on patients' sleep patterns and energy levels, disease symptoms not included as clinical measures, that persist after the cessation of zoster-associated pain; and gives a measure of the impact of zoster on the patient, which includes unmeasured and measured levels of severity.