Patient-based assessments of quality of life in newly diagnosed epilepsy patients: validation of the NEWQOL

PURPOSE: In epilepsy, patient-based assessments are increasingly used as outcome measures in clinical trials of novel therapies alongside the traditional clinical measures of efficacy. The objective of this study was to validate psychometrically a quality of life (QOL) measure developed for use with recently diagnosed epilepsy patients. METHODS: The NEWQOL (Quality of Life in Newly Diagnosed Epilepsy Instrument) is a 93-item self-administered battery designed to assess QOL in patients with new-onset epilepsy. NEWQOL consists of eight multi-item scales (13 subscales) measuring several health parameters: Anxiety, Depression, Social Activities, Symptoms, Locus of Control/ Mastery, Neuropsychological Problems (includes the following subscales: Fatigue, Memory, Concentration, Motor Skills, and Reading), Social Stigma, Worry, Work Limitations, and several single-item measures (General Health, Number of Seizures, Social Limitations, Social Support, Self Concept, Ambition Limitations, Health Transition, and General Limitations). The NEWQOL was collected at baseline and 1 week post-baseline from 108 patients in the U.K. and U.S. RESULTS: All of the multi-item scales had high item discriminant validity, good test-retest reliability, and acceptable levels of internal consistency reliability; all but the Reading and Stigma subscales had negligible floor and ceiling effects. General linear models were used to examine the known groups validity of NEWQOL. Significant differences were observed in the Worry, Symptoms, Summary Neuropsychological Scales, and all Neuropsychological subscales (Memory, Fatigue, Concentration, Motor Skills, and Reading), indicating poorer functioning in the more frequent or severe seizure groups. CONCLUSIONS: Results from this study offer supportive evidence that NEWQOL has good validity and reliability and can discriminate between patient groups, particularly in relation to symptoms and psychological problems. We conclude that NEWQOL represents a useful measure for future studies in this patient population.